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2.6: Community Interactions - Biology

2.6: Community Interactions - Biology


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Each species in an ecosystem is considered a population. When multiple species in an ecosystem are considered together, this is called a community. All living organisms are considered to be a part of the community in a given ecosystem.

What is the difference between a community and an ecosystem?

Pollination

One important community interaction we study in botany (in addition to mycorrhizae) is pollination. This is the transfer of pollen from one plant to another and can be mediated by animals, water, wind, or another mechanism. Since we are talking about community interactions, we will focus on animal pollination. Many flowering plants have evolved over time to attract a specific animal pollinator. Because the plant often provides food in the form of nectar or pollen, the pollinator often relies on this relationship as well and coevolves with the plant. One interesting example of this coevolution is the pollination of figs by parasitic wasps.

The Story of the Fig and the Wasp

Figs are made of many small flowers in an inside-out inflorescence called a syconium. How, then, are these flowers pollinated to develop into fruits? Figs are pollinated by tiny chalcid wasps known as fig wasps. In the spring, female fig wasps laden with pollen and fertilized eggs enter into the fig syconium through a small opening at the top. As she enters, her wings are ripped off, making her unable to leave again. She has reached her destination.

As she walks along the tops of the flowers, which are in their female stage, she lays her eggs inside the ovaries by inserting a long tube called an ovipositor down through the style.

Pollen falls off of her body onto the flowers and travels down the styles as well to fertilize the ovaries. Each flower she deposits an egg into will develop into a wasp instead of a fruit. However, some of the styles are longer than others, and in these she will not be able to lay her eggs. These flowers will develop into the fig fruit, while the others will serve as nurseries for the fig's strange pollinators.

The male wasps hatch first. Blind and wingless, they roam around the enclosed inflorescence, impregnating their still-sleeping sisters. As carbon dioxide builds up within the chamber, they begin to suffocate and burrow out through the sides of the figs, allowing oxygen to flow back in.

After their brothers have died, the females hatch, climbing over the flowers that are now in their male stage, collecting pollen and stuffing it into pouches on their bodies. The young female wasps, laden with pollen and fertilized eggs, leave the fig through the tunnels their brothers made and fly off to find a developing fig to lay their eggs and pollinate the enclosed florets. The timeline of a fig wasp's life is intricately interwoven into the phenology of the fig tree.

View the diagram on the following page and identify the stages in the connected life cycles of these organisms. If available in lab or on your field trip, cut open a fig to view the florets developing inside the syconium.

Is this relationship a parasitism or mutualism? Explain your reasoning.


Community Interactions in Ecosystems

Biomes as different as grasslands and estuaries share something extremely important. They have populations of interacting species. Moreover, species interact in the same basic ways inall biomes. For example, all biomes have some species that prey on other species for food. Species interactions are important biotic factors in ecological systems. The focus of study of species interactions is the community.

What is a Community?

In ecology, a community is the biotic component of an ecosystem. It consists of populations of different species that live in the same area and interact with one another. Like abiotic factors, such as climate or water depth, species interactions in communities are important biotic factors in natural selection. The interactions help shape the evolution of the interacting species. Three major types of community interactions are predation, competition, and symbiosis.

Predation

Predation is a relationship in which members of one species (the predator) consume members of other species (the prey). The lions and cape buffalo in Figure 1 are classic examples of predators and prey. In addition to the lions, there is another predator in this figure. Can you find it? The other predator is the cape buffalo. Like the lion, it consumes prey species, in this case species of grasses. Predator-prey relationships account for most energy transfers in food chains and webs.

Figure 1: An adult male lion and a lion cub feed on the carcass of a South African cape buffalo.

Types of Predators

The lions in Figure 1 are true predators. In true predation, the predator kills its prey. Some true predators, like lions, catch large prey and then dismember and chew the prey before eating it. Other true predators catch small prey and swallow it whole. For example, snakes swallow mice whole.

Some predators are not true predators because they do not kill their prey. Instead, they graze on their prey. In grazing, a predator eats part of its prey but rarely kills it. For example, deer graze on plants but do not usually kill them. Animals may also be “grazed” upon. For example, female mosquitoes suck tiny amounts of blood from animals but do not harm them, although they can transmit disease.

Predation and Populations

True predators help control the size of prey populations. This is especially true when a predator preys on just one species. Generally, the predator-prey relationship keeps the population size of both species in balance. This is shown in Figure 2. Every change in population size of one species is followed by a corresponding change in the population size of the other species. Generally, predator-prey populations keep fluctuating in this way as long as there is no outside interference.

Figure 2: As the prey population increases, the predator population starts to rise. With more predators, the prey population starts to decrease, which, in turn, causes the predator population to decline. This pattern keeps repeating. There is always a slight lag between changes in one population and changes in the other population.

Some predator species are known as keystone species, because they play such an important role in their community. Introduction or removal of a keystone species has a drastic effect on its prey population. This, in turn, affects populations of many other species in the community. For example, some sea star species are keystone species in coral reef communities. The sea stars prey on mussels and sea urchins, which have no other natural predators. If sea stars are removed from a coral reef community, mussel and sea urchin populations would have explosive growth, which in turn would drive out most other species and destroy the reef community.

Sometimes humans deliberately introduce predators into an area to control pests. This is called biological pest control. One of the earliest pests controlled in this way was a type of insect, called a scale insect. The scale insect was accidentally introduced into California from Australia in the late 1800s. It had no natural predators in California and was destroying the state’s citrus trees. Then, its natural predator in Australia, a type of beetle, was introduced into California in an effort to control the scale insect. Within a few years, the insect was completely controlled by the predator. Unfortunately, biological pest control does not always work this well. Pest populations often rebound after a period of decline.

Adaptations to Predation

Both predators and prey have adaptations to predation. Predator adaptations help them capture prey. Prey adaptations help them avoid predators. A common adaptation in both predator and prey species is camouflage, or disguise. One way of using camouflage is to blend in with the background. Several examples are shown in Figure 3.

Figure 3: Can you see the crab in the photo on the left? It is camouflaged with algae. The preying mantis in the middle photo looks just like the dead leaves in the background. The stripes on the zebras in the right photo blend the animals together, making it hard to see where one zebra ends and another begins.

Another way of using camouflage is to look like a different, more dangerous animal. Using appearance to “mimic” another animal is called mimicry. Figure 4 shows an example of mimicry. The moth in the figure has markings on its wings that look like the eyes of an owl. When a predator comes near, the moth suddenly displays the markings. This startles the predator and gives the moth time to fly away.

Figure 4: The moth on the left mimics the owl on the right. This “disguise” helps protect the moth from predators.

Some prey species have adaptations that are the opposite of camouflage. They have bright colors or other highly noticeable traits that serve as a warning for their predators to stay away. For example, some of the most colorful butterflies are poisonous to birds, so birds have learned to avoid eating them. By being so colorful, the butterflies are more likely to be noticed—and avoided—by their predators.

Predation, Natural Selection, and Co-evolution

Adaptations to predation come about through natural selection. When a prey organism avoids a predator, it has higher fitness than members of the same species that were killed by the predator. The organism survives longer and may produce more offspring. As a result, traits that helped the prey organism avoid the predator gradually become more common in the prey population.

Evolution of traits in the prey species leads to evolution of corresponding traits in the predator species. This is called co-evolution. In co-evolution, each species is an important factor in the natural selection of the other species. Predator-prey co-evolution is illustrated by rough-skinned newts and common garter snakes, both shown in Figure 5. Through natural selection, newts evolved the ability to produce a strong toxin. In response, garter snakes evolved the ability to resist the toxin, so they could still safely prey upon newts. Then, newts evolved the ability to produce higher levels of toxin. This was followed by garter snakes evolving resistance to the higher levels. In short, the predator-prey relationship led to an evolutionary “arms race,” resulting in extremely high levels of toxin in newts.

Figure 5: The rough-skinned newt on the left is highly toxic to other organisms. Common garter snakes, like the one on the right, have evolved resistance to the toxin.

Competition

Competition is a relationship between organisms that strive for the same limited resources. The resources might be food, nesting sites, or territory. Two different types of competition are intraspecific and interspecific competition.

Intraspecific competition occurs between members of the same species. For example, two male birds of the same species might compete for mates in the same territory. Intraspecific competition is a necessary factor in natural selection. It leads to adaptive changes in a species through time.
Interspecific competition occurs between members of different species. For example, two predator species might compete for the same prey. Interspecific competition takes place in communities of interacting species.

Interspecific Competition and Extinction

When populations of different species in a community depend on the same resources, there may not be enough resources to go around. If one species has a disadvantage, such as more predators, it may get fewer of the necessary resources. As a result, members of that species are less likely to survive, and the species will have a higher death rate than the other species. Fewer offspring will be produced and the species may eventually die out in the area.

In nature, interspecific competition has often led to the extinction of species. Many other extinctions have occurred when humans introduced new species into areas where they had no predators. For example, rabbits were introduced into Australia in the mid-1800s for sport hunting. Rabbits had no predators in Australia and quickly spread throughout the continent. Many species of Australian mammals could not successfully compete with rabbits and went extinct.

Interspecific Competition and Specialization

Another possible outcome of interspecific competition is the evolution of traits that create distinct differences among the competing species. Through natural selection, competing species can become more specialized. This allows them to live together without competing for the same resources. An example is the anolis lizard. Many species of anolis live and prey on insects in tropical rainforests. Competition among the different species led to the evolution of specializations. Some anolis evolved specializations to prey on insects in leaf litter on the forest floor. Others evolved specializations to prey on insects on the branches of trees. This allowed the different species of anolis to co-exist without competing.

Symbiotic Relationships

Symbiosis is a close association between two species in which at least one species benefits. For the other species, the outcome of the association may be positive, negative, or neutral. There are three basic types of symbiotic relationships: mutualism, commensalism, and parasitism.

Mutualism is a symbiotic relationship in which both species benefit. Lichen is a good example. A lichen is not a single organism but a fungus and an alga. The fungus absorbs water from air and minerals from rock or soil. The alga uses the water and minerals to make food for itself and the fungus. Another example involves goby fish and shrimp (see Figure 6). The nearly blind shrimp and the fish spend most of their time together. The shrimp maintains a burrow in the sand in which both the goby and the shrimp live. When a predator comes near, the fish touches the shrimp with its tail as a warning. Then, both fish and shrimp retreat to the burrow until the predator is gone. Each gains from this mutualistic relationship: the shrimp gets a warning of approaching danger, and the fish gets a safe home and a place to lay its eggs.

Figure 6: The multicolored shrimp in the front and the green goby fish behind it have a mutualistic relationship. The shrimp shares its burrow with the fish, and the fish warns the shrimp when predators are near. Both species benefit from the relationship.

Co-evolution often occurs in species involved in mutualistic relationships. Many examples are provided by flowering plants and the species that pollinate them. Plants have evolved flowers with traits that promote pollination by particular species. Pollinator species, in turn, have evolved traits that help them obtain pollen or nectar from certain species of flowers. For example, the plant with tube-shaped flowers shown in Figure 7 co-evolved with hummingbirds. The birds evolved long, narrow beaks that allowed them to sip nectar from the tubular blooms.

Figure 7: This hummingbird’s long slender beak and the large tubular flowers of the plant are a good match, which resulted from a long period of co-evolution. Their relationship is an example of mutualism. The hummingbird uses nectar from the flowers for food and pollinates the flowers in the process.

Commensalism

Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. In commensalism, one animal typically uses another for a purpose other than food. For example, mites attach themselves to larger flying insects to get a “free ride,” and hermit crabs use the shells of dead snails for shelter.

Co-evolution explains some commensal relationships. An example is the human species and some of the species of bacteria that live inside humans. Through natural selection, many species of bacteria have evolved the ability to live inside the human body without harming it.

Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed. Some parasites live on the surface of their host. Others live inside their host, entering through a break in the skin or in food or water. For example, roundworms are parasites of the human intestine. The worms produce huge numbers of eggs, which are passed in the host’s feces to the environment. Other humans may be infected by swallowing the eggs in contaminated food or water. This usually happens only in places with poor sanitation.

Some parasites eventually kill their host. However, most parasites do not. Parasitism in which the host is not killed is a successful way of life and very common in nature. About half of all animal species are parasitic in at least one stage of their lifecycle. Many plants and fungi are parasitic during some stages, as well. Not surprisingly, most animals are hosts to one or more parasites.

Species in parastic relationships are likely to undergo co-evolution. Host species evolve defenses against parasites, and parasites evolve ways to evade host defenses. For example, many plants have evolved toxins that poison plant parasites such as fungi and bacteria. The microscopic parasite that causes malaria in humans has evolved a way to evade the human immune system. It hides out in the host’s blood cells or liver where the immune system cannot find it.

Ecological Succession

Ecological succession is the process by which a whole community of populations changes through time. It occurs following a disturbance that creates unoccupied areas for colonization. The first colonizer species are called pioneer species. They change the environment and pave the way for other species to move into the area. Succession occurs in two different ways, depending on the starting conditions: primary succession and secondary succession.

Primary Succession

Primary succession occurs in an area that has never been colonized before. Generally, the area is nothing but bare rock. This type of environment can come about in a number of ways, including:

• Lava can flow from a volcano and harden into rock.
• A glacier can retreat and leave behind bare rock.
• A landslide can uncover a large area of bare rock.

After the disturbance, pioneer species move in first. They include bacteria and lichens that can live on bare rock. Along with wind and water, these pioneer species help to weather the rock and form soil. Once soil begins to form, other plants can move in. At first, the plants include grasses and other species that can grow in thin, poor soil. As more plants grow and die, organic matter is added to the soil. This improves the soil and helps it hold water. The improved soil allows shrubs and trees to move into the area. An example of primary succession is shown in Figure 8.

Figure 8: On an island near New Zealand, bare rocks from a volcanic eruption are slowly being colonized by pioneer species.

Secondary Succession

Secondary succession occurs in a formerly inhabited area that was disturbed. The disturbance could be a fire, flood, or human action such as logging or farming. Secondary succession can occur faster than primary succession because the soil is already in place. In secondary succession, the pioneer species are plants that are adapted to exploit disturbances rather than bare rock. They typically include plants such as grasses, birch trees, and fireweed. Organic matter from the pioneer species improves the soil so other trees and plants can move into the area. An example of secondary succession is shown in Figure 9.

Figure 9: This formerly cultivated farm field in Poland is reverting to deciduous forest in the process of secondary succession.

Climax Communities

Many early ecologists thought that a community always went through a predictable series of stages during succession. They also thought that the end result of succession was a final stage called a climax community. The type of climax community was believed to be determined mainly by climate. For example, in mild, wet temperate climates, evergreen rainforests were thought to be the predictable end result of succession. Climax communities were also thought to be very biodiverse. This characteristic, in turn, was believed to make them stable, or resistant to change.

Today, most ecologists think that change, rather than stability, is more characteristic of ecological systems. They argue that most communities are disturbed too often to reach a climax community stage. They also argue that high biodiversity does not always make a community stable. Some communities that have low biodiversity, such as salt marshes, are very resistant to change. On the other hand, some communities that have high biodiversity, such as coral reefs, are easily affected by disturbances. High biodiversity may increase species interactions. This, in turn, may make species more interdependent and communities more likely to change when they are disturbed.


Courses with the BIOLOGY Subject

The online catalog includes the most recent changes to courses and degree requirements that have been approved by the Faculty Senate, including changes that are not yet effective. Courses showing two entries of the same number indicate that the course information is changing. The most recently approved version is shown first, followed by the older version, in gray, with its last-effective term preceding the course title. Courses shown in gray with only one entry of the course number are being discontinued. Course offerings by term can be accessed by clicking on the term links when viewing a specific campus catalog.

Biology (BIOLOGY)

101 [BSCI] Biology of Humans 3 The biology of good health and longevity evaluation of lifestyle choices consideration of each body system and the potential for disease and disorder. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

102 [BSCI] General Biology 4 (3-3) Enrollment not allowed if credit for BIOLOGY 105 already earned. Understanding current and future advances in biology as 'citizen scientists'. Lecture and laboratory not for students majoring in the life sciences. Credit not allowed for students who have already completed BIOLOGY 105. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

103 Science and Scientific Thinking 1 (0-3) Exploring science as a tool for understanding nature using case studies, experimentation, and data analysis. Topics range from atoms to ecosystems including physiology, inheritance, and the carbon cycle. Credit not granted towards elective requirements for majors in the School of Biological Sciences. Recommended for students with an ALEKS math placement score of less than 45%. (Crosslisted course offered as BIOLOGY 103, SCIENCE 103).

105 General Biology Laboratory 1 (0-3) Course Prerequisite: Junior standing. Enrollment not allowed if credit for BIOLOGY 102 already earned. Understanding biology as a science and its effect on issues within society. Laboratory only. Credit not allowed for students who have already completed BIOLOGY 102. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

106 [BSCI] Introductory Biology: Organismal Biology 4 (3-3) Course Prerequisite: One of the following -- a minimum ALEKS math placement score of 40%, MATH 100 with an S, MATH 101 with a C or better, MATH 103 or higher, BIOLOGY 103 with a C or better, BIOLOGY 102, BIOLOGY 120, or 3 credits of biology with a lab. One semester of a two semester sequence (BIOLOGY 106/107 or BIOLOGY 107/106) for science majors and pre-professional students. Biology of organisms plants, animals, ecology and evolution.

107 [BSCI] Introductory Biology: Cell Biology and Genetics 4 (3-3) Course Prerequisite: Minimum 2 credits 100 level CHEM or concurrent enrollment. First or second semester of a one-year sequence (BIOLOGY 106/107 or BIOLOGY 107/106) for science majors and pre-professional students. Cell biology and genetics of prokaryotes and eukaryotes.

110 Biological Perspectives on Environmental Issues 3 Current case studies of human interaction with the environment exploring concepts in ecology, biodiversity, global chemical cycles, and climate change. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

111 [BSCI] Laboratory Experiments in Biology and Genetics 1 (0-3) Scientific method and its application to a diverse range of biology and genetics topics and research questions. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

120 [BSCI] Introductory Botany 4 (3-3) Introduction to plant science, highlighting certain aspects of plant biology and current research and how these relate to us all in the modern world. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

125 Genetics and Society 3 Genetic topics in media and daily life including human health, agriculture, ecology and forensics for the educated non-biologist. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

135 Animal Natural History 3 Identification, life history, habitat relations, ecology, behavior, and conservation of animals commonly found in the Pacific Northwest. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

140 [BSCI] Introduction to Nutritional Science 3 Information related to dietary sources of nutrients, their functions in the body, physiologic and environmental factors that govern nutrient requirements, and guidelines for optimal dietary patterns. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

150 [BSCI] Evolution 3 Basic principles and implications of Darwinian evolution. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

201 Contemporary Biology 1 Course Prerequisite: BIOLOGY 101, 102, 106, 107, 120, or MBIOS 101. Biological information that provides a framework for understanding life processes impact of biological information on human affairs.

210 Your Future in Life Sciences 2 Exploration of career options in biological sciences with faculty and outside speakers guide to preparing resume and career plans. (Crosslisted course offered as SCIENCE 210, BIOLOGY 210).

220 Medical Terminology 2 Course Prerequisite: BIOLOGY 101, 102, 106, 107, or KINES 262. Terms and word constructions for health care occupations format and function of medical records.

221 Exploring Health Careers 1 Introduction to human and animal health care careers. S, F grading.

225 Preparation for the Health Care Workplace 2 (1-3) Basic content and skills to prepare for health related internships.

251 Introductory Human Physiology 4 (3-3) Course Prerequisite: BIOLOGY 102, 106, or 107. Basic physiological processes in humans from the cellular to the organismal level. Credit not granted for both BIOLOGY 251 and 353.

298 [BSCI] Honors Biology for Non-Science Majors 4 (3-3) Course Prerequisite: Must be an Honors student. Understanding the natural world from a biological perspective for non-science majors.

301 General Genetics 4 Course Prerequisite: BIOLOGY 106 or 120 BIOLOGY 107 CHEM 101 or 105 CHEM 102 or 106. Principles of modern and classical genetics. (Crosslisted course offered as MBIOS 301, BIOLOGY 301).

307 [DIVR] Biology of Women 3 Course Prerequisite: BIOLOGY 102 or 106. Biological basis of sex and its relationship to body function, women and health care, and the impact of social and cultural perspectives on the experience of being female. (Crosslisted course offered as BIOLOGY 307, WOMEN ST 307).

308 [BSCI] Marine Biology 3 Course Prerequisite: BIOLOGY 106 sophomore standing. Introduction to the marine environment including oceanic, near-shore and estuarine communities of organisms and their roles and interactions.

315 Gross and Microanatomy 4 (3-3) Course Prerequisite: At least 3 hours of BIOLOGY sophomore standing cumulative WSU GPA 2.5 or better. Gross and microscopic anatomy of the human body. Recommended for pre-health care professionals only.

321 [M] Principles of Animal Development 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 107. Experimental analyses of development and descriptive and comparative examination of embryology emphasis on the chordates. Recommended preparation: BIOLOGY 301 or MBIOS 301.

322 [M] Invertebrate Biology 4 (3-3) Course Prerequisite: BIOLOGY 106. Phylogenetic relationships, development, and functional ecology of the invertebrate animals.

324 Comparative Vertebrate Anatomy 4 (2-6) Course Prerequisite: BIOLOGY 106. Evolution of vertebrates and their organ systems correlation of structural modification with function. Cooperative: Open to UI degree-seeking students.

330 Principles of Conservation 3 Course Prerequisite: BIOLOGY 102, 106, or 107. Conservation of major natural resources through a biological approach philosophical, economic, and political aspects of important conservation issues.

332 [M] Systematic Botany 4 (3-3) Course Prerequisite: BIOLOGY 106 or 120. Identification and classification of vascular plants with emphasis on the local flora.

333 [BSCI] Human Nutrition and Health 3 Course Prerequisite: BIOLOGY 102, 106, 107, 251, 315, or concurrent enrollment in BIOLOGY 251. Credit not granted for students who have already completed BIOLOGY 233 with a grade of C or above. Foundations in nutritional science and its relationship to human health through the application of fundamental principles of biology.

335 [M] Genome Biology 3 Course Prerequisite: BIOLOGY 301. Comparative analysis of genomes from bacteria to humans including methods for sequencing, genotyping, annotation of genomes, population genetics and evolution.

340 Introduction to Mathematical Biology 3 Course Prerequisite: MATH 140 with a C or better, or MATH 172 with a C or better, or MATH 182 with a C or better BIOLOGY 101, BIOLOGY 102, BIOLOGY 106, or BIOLOGY 107. Mathematical biology and development of mathematical modeling for solutions to problems in the life sciences. (Crosslisted course offered as MATH 340, BIOLOGY 340).

350 Comparative Physiology 4 (3-3) Course Prerequisite: BIOLOGY 107 CHEM 345. Analysis of systems and integrative physiology with an emphasis on evolutionary adaptation among mammalian and non-mammalian vertebrates.

352 Cells 3 Course Prerequisite: BIOLOGY 107 CHEM 345. Diversity and processes at the cellular level structure and function.

353 Advanced Human Physiology 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 107. Function and control at the organ-organismic level with emphasis on mammals, including humans emphasis on human health science applications. Credit not granted for both BIOLOGY 251 and 353. Recommended preparation: BIOLOGY 315 or 354.

354 Human Anatomy for Health Occupations 4 (3-3) Course Prerequisite: BIOLOGY 107 CHEM 102 or 345. History and anatomy of humans with non-cadaver-based laboratory utilizing preserved and histological specimens, models and software.

360 Molecular Processes of Living Organisms 3 Course Prerequisite: BIOLOGY 107. Exploration of fundamental molecular processes to encourage thinking beyond biological species in order to comprehend larger-scale biological issues and relevance for society.

370 [M] Ecology of Health and Disease 4 (3-3) Course Prerequisite: BIOLOGY 106 CHEM 102 or 105. Enrollment in BIOLOGY 370 not allowed if credit already earned for BIOLOGY 372. Ecology of species interactions in changing environments and how they influence human and animal health. Credit not granted for both BIOLOGY 370 and 372. Field trips may be required.

372 [M] General Ecology 4 (3-3) Course Prerequisite: BIOLOGY 106 CHEM 102 or 105. Enrollment in BIOLOGY 372 not allowed if credit already earned for BIOLOGY 370. Relationship of organisms with physical and biotic components of their environment at the population, community, and ecosystem level. Credit not granted for both BIOLOGY 370 and 372. Field trips may be required.

390 Stream Monitoring 1 (0-3) Course Prerequisite: BIOLOGY 101, 102, or 106 CHEM 101 or 105 junior standing. Principles and methods of water quality monitoring, including habitat assessment, water chemistry, and biological assessment. Field work and independent research required.

393 [M] Professional Communications in Biology 2 Course Prerequisite: Admitted to the major in Biology or Zoology. Literature investigation, oral presentation and written reports of selected topics in biology.

394 Medicine as a Career 2 Course Prerequisite: Junior standing. Current issues in medicine ethical, financial, and personal aspects of medical practice. S, F grading.

395 Evolutionary Medicine 3 Course Prerequisite: BIOLOGY 301. Modern medical issues from an evolutionary perspective, integrated with other biological fields in medical research topics include disease diversity, immune function, the evolution of virulence, human disease management, cancer, obesity, and human mental and reproductive health issues and their management.

401 [CAPS] Plants and People 3 Course Prerequisite: BIOLOGY 106 or 120 BIOLOGY 107 junior standing. Relationships between plants and people, especially cultural and economic applications of plants.

402 [M] Beneficial Microbes in Nature and Society 3 Course Prerequisite: BIOLOGY 372, 403, or 405 junior standing. In-depth investigations of interdisciplinary topics addressing the importance of beneficial microbes to organisms, natural systems, and society from across the disciplines of microbiology, medicine, evolutionary ecology, and agricultural science.

403 Evolutionary Biology 3 Course Prerequisite: BIOLOGY 301. The survey of evidence for evolution and operation of evolutionary processes that influence adaptation, diversification and speciation in organisms.

405 Principles of Organic Evolution 3 (2-3) Course Prerequisite: BIOLOGY 301. The evolutionary processes that influence adaptation, population differentiation, and speciation in organisms.

408 [CAPS] [M] Contemporary Genetics 3 Course Prerequisite: MBIOS / BIOLOGY 301 with a C or better junior standing. Consideration of the state-of-the-art genetic technologies and their impact on society, environment and the economy.

409 Plant Anatomy 4 (2-6) Course Prerequisite: BIOLOGY 106 or 120. Developmental anatomy and morphology of vascular plants economic forms. Credit not granted for both BIOLOGY 409 and BIOLOGY 509. Offered at 400 and 500 level.

410 Marine Ecology 3 Course Prerequisite: BIOLOGY 106. The ecology and conservation of marine organisms, communities, and ecosystems.

412 Biology of Fishes 3 (2-3) Course Prerequisite: BIOLOGY 106. Evolution, identification, life history, and characteristics of important fish species.

418 Parasitology 4 (3-3) Course Prerequisite: BIOLOGY 102 or BIOLOGY 106 junior standing. Types of associations, life cycles, control, prevention, and modifications of parasites examination of parasitic protozoa and helminths.

420 Plant Physiology 3 Course Prerequisite: BIOLOGY 106 or 120. Water relations, mineral nutrition, photosynthesis, respiration, and growth of plants. Recommended: Organic chemistry.

421 Plant Physiology Laboratory 1 (0-3) Course Prerequisite: BIOLOGY 420 or concurrent enrollment. Laboratory for Biol 420.

423 Ornithology 4 (3-3) Course Prerequisite: BIOLOGY 106. Ecology, systematics, and evolution of birds. Field trips required include two Saturdays.

428 Mammalogy 4 (3-3) Course Prerequisite: BIOLOGY 106. Ecology, systematics, and evolution of mammals.

430 Methods of Teaching Secondary Science I 3 Course Prerequisite: Junior standing. Application of learning and theory and philosophy and structure of science in teaching middle and secondary school science courses. (Crosslisted course offered as BIOLOGY 430, MBIOS 480, TCH LRN 430).

431 Methods of Teaching Secondary Science II 3 Course Prerequisite: BIOLOGY 430, MBIOS 480, or TCH LRN 430 junior standing. Integration of assessment, curricular, and technological tools into instruction that aligns with learning theory and the philosophy/structure of science. (Crosslisted course offered as BIOLOGY 431, MBIOS 481, TCH LRN 431).

432 [M] Biology of Amphibians and Reptiles 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 372 or SOE 300. Characteristics, evolution, and systematics patterns of distribution adaptive strategies interactions between humans and amphibians and reptiles.

438 [M] Animal Behavior 3 (2-3) Course Prerequisite: BIOLOGY 106. Biological study of animal behavior as viewed from ethological, genetic, developmental, ecological, and evolutionary perspectives.

446 Mutualism and Symbiosis 3 Course Prerequisite: BIOLOGY 372, 403, or 405. Critical evaluation of the ecology, evolution, and molecular biology of mutualism and symbiosis. Credit not granted for both BIOLOGY 446 and 546. Offered at 400 and 500 level.

456 Neuroethology 3 Course Prerequisite: BIOLOGY 301, MBIOS 303, or 300-level NEUROSCI course STAT 412 or concurrent enrollment. Introduction to neural mechanisms underlying natural animal behaviors from the cellular level to the organismal level.

462 Community Ecology 3 Course Prerequisite: BIOLOGY 372 with a C or better. Assembly, essential properties, levels of interactions, succession, and stability of natural communities emphasizes an experimental approach to community investigation. Credit not granted for both BIOLOGY 462 and BIOLOGY 562. Recommended preparation: BIOLOGY 372. Offered at 400 and 500 level.

465 Field Stream Ecology 2 Course Prerequisite: BIOLOGY 372. Ecological roles of immature insects in different size streams pattern changes along the stream continuum other ecological characteristics.

469 [M] Ecosystem Ecology and Global Change 3 Historic and current factors controlling the function of ecosystems and their responses to natural and human caused global change. Credit not granted for both BIOLOGY 469 and 569. Offered at 400 and 500 level. Cooperative: Open to UI degree-seeking students.

470 Diversity of Plants 3 Morphological, life history, and ecological diversity of major plant clades emphasis on principles of homology, character transformation, and macroevolution.

473 [CAPS] [M] Evolution and Society 3 Course Prerequisite: ANTH 260 or BIOLOGY 301 junior standing. Survey of how the theory of evolution is used to better understand ourselves, the societies in which live, and the biological world on which we depend. Recommended preparation: BIOLOGY 405 or concurrent enrollment. (Crosslisted course offered as BIOLOGY 473, ANTH 473).

474 Computational Biology 4 (3-3) Course Prerequisite: BIOLOGY 301 MATH 140 or 171 STAT 212, 412, or PSYCH 311. Theory and current literature on a wide range of computational techniques used to address and solve problems in biology a practical introduction to R/python as scientific languages useful in the solution of problems in biology.

475 Systems Biology of Reproduction 3 Current literature based course on systems biology with a molecular/epigenetic to physiological level understanding of cell, development, disease, and evolutionary biology. Credit not granted for both BIOLOGY 475 and 575. Offered at 400 and 500 level.

476 Epigenetics and Systems Biology 3 Course Prerequisite: BIOLOGY 301. Current literature based course on epigenetics and systems biology with topics in environmental epigenetics, disease etiology, and role epigenetics in evolutionary biology. Credit not granted for both BIOLOGY 476 and 576. Offered at 400 and 500 level.

480 [M] Writing in Biology 2 Course Prerequisite: Admitted to the major in Biology or Zoology. Discussion and practice in relating thinking and writing popular and professional communication in biology.

483 [CAPS] [M] Organisms and Global Change 3 Course Prerequisite: BIOLOGY 372 junior standing. Interaction between organisms and global change across scales of biology.

485 [CAPS] Biology of the Oceans 3 Course Prerequisite: BIOLOGY 106 junior standing. Interdisciplinary capstone course that explores the ocean world from molecules to ecosystems in the context of scientific discovery and society.

486 [M] Marine Invertebrate Communities 3 (2-3) Course Prerequisite: BIOLOGY 106. Survey of marine invertebrates and their habitats. One-week field/lab course at a marine station.

489 [CAPS] [M] Synthesis and Communication of Independent Research 3 Course Prerequisite: 2 credits BIOLOGY 499 admitted to major in Biology or Zoology junior standing by permission only. Integration of broad topics from biology and other science fields to inform scientific writing and presentation of independent research projects.

490 [M] Professional Seminar in Physical Therapy 2 Course Prerequisite: By permission only. Consideration of treatment modalities and health issues in physical therapy and related disciplines. A, S, F grading.

491 Clinical Experience V 1-4 May be repeated for credit cumulative maximum 20 hours. Course Prerequisite: PSYCH 105 BIOLOGY 315 junior standing by permission only. Work experience under supervision of a qualified professional in a clinical setting. S, F grading.

492 Topics in Biology V 1-3 May be repeated for credit cumulative maximum 6 hours.

494 Seminar in Mathematical Biology 1 May be repeated for credit cumulative maximum 4 hours. Course Prerequisite: MATH 140 with a C or better, or MATH 172 with a C or better, or MATH 182 with a C or better BIOLOGY 101, BIOLOGY 102, BIOLOGY 106, or BIOLOGY 107. Oral presentation of research approaches, research results and literature review of mathematical biology including mathematical modeling of biological systems. (Crosslisted course offered as MATH 494, BIOLOGY 494). Cooperative: Open to UI degree-seeking students. S, F grading.

495 Internship in Biology, Botany, and Zoology V 1-4 May be repeated for credit cumulative maximum 8 hours. Course Prerequisite: By permission only. Experience in work related to specific career interests. S, F grading.

496 [M] Special Problems and Reports V 1-4 Course Prerequisite: By permission only. Independent project with written project proposal, progress report, and final report required. S, F grading.

497 Instructional Practicum V 1-4 May be repeated for credit cumulative maximum 8 hours. Academic traineeship in laboratory teaching and tutoring.

499 Special Problems V 1-4 May be repeated for credit. Course Prerequisite: By permission only. Independent study conducted under the jurisdiction of an approving faculty member may include independent research studies in technical or specialized problems selection and analysis of specified readings development of a creative project or field experiences. S, F grading.

500 Seminar 1 May be repeated for credit. S, F grading.

501 Proposal Defense Seminar 2 Research proposal defense as part of the preliminary examination for candidacy in the Ph.D. program. S, F grading.

504 Experimental Methods in Plant Physiology 4 (2-6) Advanced techniques and instrumental methods applicable to research in plant physiology.

509 Plant Anatomy 4 (2-6) Developmental anatomy and morphology of vascular plants economic forms. Credit not granted for both BIOLOGY 409 and BIOLOGY 509. Offered at 400 and 500 level.

512 Molecular Mechanisms of Plant Development 3 Physiology of growth metabolism during development and reproduction.

513 Plant Metabolism 3 Metabolic processes unique to plants, including the primary incorporation of nitrogen, sulfur, carbon dioxide and phosphate into bio-molecules.

514 Fish Genetics 2 Chromosomal, biochemical, quantitative, and ecological aspects of fish genetics with emphasis on applications to aquaculture and fish management. Cooperative: Open to UI degree-seeking students.

517 Stress Physiology of Plants 3 Temperature, light, salinity, water effects on physiological processes mechanistic understanding of stress.

519 Introduction to Population Genetics 3 Survey of basic population and quantitative genetics. Cooperative: Open to UI degree-seeking students.

520 Conservation Genetics 2 Genetic studies and approaches relevant to efforts to conserve threatened and endangered populations of organisms.

521 Quantitative Genetics 3 Course Prerequisite: BIOLOGY 519. Fundamentals of quantitative genetics evolutionary quantitative genetics. Cooperative: Open to UI degree-seeking students.

531 Principles of Systematic Biology 3 Systematic theory history and current views approaches to phylogenetic analysis and classification.

533 Modern Methods in Phylogenetics 4 (2-6) Selecting, gathering, and analyzing morphological, cytological, molecular data for phylogenetic and evolutionary studies.

534 Modern Methods in Population Genomics 3 Course Prerequisite: BIOLOGY 519. Problems and prospects of designing a study with genomic data: from raw data to demography and selection inferences.

537 Plant Cell Biology 3 Structure and function of plant cells including membrane biology, protein targeting and molecular signaling with emphasis on current research.

540 Stable Isotope Theory and Methods 3 Theory and practice of measuring stable isotope ratios of biologically important elements. Cooperative: Open to UI degree-seeking students.

544 Nitrogen Cycling in the Earth's Systems 3 Nitrogen dynamics in terrestrial, aquatic, and atmospheric systems nitrogen transformations in natural and managed systems and responses to human activities. (Crosslisted course offered as BIOLOGY 544, SOIL SCI 544).

545 Statistical Genomics 3 (2-3) Develop concepts and analytical skills for modern breeding by using Genome-Wide Association Study and genomic prediction in framework of mixed linear models and Bayesian approaches. (Crosslisted course offered as CROP SCI 545, ANIM SCI 545, BIOLOGY 545, HORT 545, PL P 545.) Recommended preparation: BIOLOGY 474 MBIOS 478. Cooperative: Open to UI degree-seeking students.

546 Mutualism and Symbiosis 3 Critical evaluation of the ecology, evolution, and molecular biology of mutualism and symbiosis. Credit not granted for both BIOLOGY 446 and 546. Offered at 400 and 500 level.

548 Evolutionary Ecology of Populations 3 Evolutionary dynamics of natural populations and the co-evolution of species. Cooperative: Open to UI degree-seeking students.

549 Behavioral Ecology 3 Examination of animal behavior from evolutionary and ecological perspectives.

556 Biochemical Adaptation 3 Relationships between enzyme/macromolecule adaptation and animal performance.

559 Hormones, Brain and Behavior 3 Classical behavioral endocrinology from molecular to whole organisms, integrating evolutionary ecology, neuroethology and behavioral neuroendocrinology.

560 Plant Ecophysiology 3 Relationships of biotic and abiotic environment to plant distribution and evolution through study of physiological processes.

561 Environmental Physiology 3 Individual and evolutionary adaptations to changing environments with emphasis on recent literature.

562 Community Ecology 3 Assembly, essential properties, levels of interactions, succession, and stability of natural communities emphasizes an experimental approach to community investigation. Credit not granted for both BIOLOGY 462 and BIOLOGY 562. Recommended preparation: BIOLOGY 372. Offered at 400 and 500 level.

563 Field Ecology 2 (0-6) Field implementation of descriptive and experimental techniques to quantify the structure, composition, and interactions within natural communities. Field trips required. Cooperative: Open to UI degree-seeking students.

564 Molecular Ecology and Phylogeography 3 Use of genetic markers for the study of ecological phenomena, including kinship, population structure, and phylogeography. Cooperative: Open to UI degree-seeking students.

565 Ecology and Evolution of Disease 3 Disease ecology and evolution with a focus on current literature. Recommended preparation: BIOLOGY 372 BIOLOGY 405. Cooperative: Open to UI degree-seeking students.

566 Mathematical Genetics 3 Mathematical approaches to population genetics and genome analysis theories and statistical analyses of genetic parameters. (Crosslisted course offered as MATH 563, BIOLOGY 566). Required preparation must include multivariate calculus, genetics, and statistics. Cooperative: Open to UI degree-seeking students.

567 Ecological Restoration 3 Introduction to major issues in restoration ecology major ecological dimensions of restoration.

568 Conservation Ecology 3 Diagnosis of endangered species, population viability analysis, invasive species ecology, landscape ecology and ecosystem management.

569 [M] Ecosystem Ecology and Global Change 3 Historic and current factors controlling the function of ecosystems and their responses to natural and human caused global change. Credit not granted for both BIOLOGY 469 and 569. Offered at 400 and 500 level. Cooperative: Open to UI degree-seeking students.

570 Diversity of Plants 3 Morphological, life history, and ecological diversity of major plant clades emphasis on principles of homology, character transformation, and macroevolution.

571 Quantitative Toolkit for Biologists 3 Course Prerequisite: STAT 512. Hands-on experience in the exploration, analysis, and interpretation of patterns in modern biological datasets.

572 Quantitative Methods and Statistics in Ecology 4 (3-3) Course Prerequisite: By permission only. Philosophy and methods of formulating hypotheses as mathematical models and confronting them with data.

573 Ancient DNA 3 The prospects and problems associated with the study of ancient DNA are explored through reading and discussing primary literature.

575 Systems Biology of Reproduction 3 Current literature based course on systems biology with a molecular/epigenetic to physiological level understanding of cell, development, disease, and evolutionary biology. Credit not granted for both BIOLOGY 475 and 575. Offered at 400 and 500 level.

576 Epigenetics and Systems Biology 3 Current literature based course on epigenetics and systems biology with topics in environmental epigenetics, disease etiology, and role epigenetics in evolutionary biology. Credit not granted for both BIOLOGY 476 and 576. Offered at 400 and 500 level.

579 Mathematical Modeling in the Biological and Health Sciences 3 Techniques, theory, and current literature in mathematical modeling in the biological and health sciences, including computational simulation. (Course offered as BIOLOGY 579, MATH 579). Cooperative: Open to UI degree-seeking students.

581 Comparative Biology of Social Traditions 3 Phylogenetic and modeling perspectives used to examine the evolution of social learning and cultural transmission in humans and other animals. (Crosslisted course offered as ANTH 581, BIOLOGY 581).

582 Professional Communication in Biology - Grant Writing 2 Mechanics and style of publishing biological research and findings adaptation of writing to various venues and audiences with emphasis on grant writing.

585 Professional Development and Training for College and University Teaching 2 Preparation for roles as teaching assistants and as instructors of undergraduate classroom education.

589 Advanced Topics in Biology V 1-3 May be repeated for credit cumulative maximum 6 hours. Recent advances in biology.

591 Seminar in Molecular Plant Sciences 1 May be repeated for credit cumulative maximum 4 hours. A cross-discipline seminar, including botany, crop and soils sciences, horticulture, plant pathology, and molecular plant sciences.

593 Seminar I 1 May be repeated for credit. Literature and problems.

597 Teaching Practicum V 1-4 May be repeated for credit cumulative maximum 4 hours. Zoology laboratory teaching internship. S, F grading.

600 Special Projects or Independent Study V 1-18 May be repeated for credit. Independent study, special projects, and/or internships. Students must have graduate degree-seeking status and should check with their major advisor before enrolling in 600 credit, which cannot be used toward the core graded credits required for a graduate degree. S, F grading.

700 Master's Research, Thesis, and/or Examination V 1-18 May be repeated for credit. Independent research and advanced study for students working on their master's research, thesis and/or final examination. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 700 credit. S, U grading.

702 Master's Special Problems, Directed Study and/or Examination V 1-18 May be repeated for credit. Independent research in special problems, directed study, and/or examination credit for students in a non-thesis master's degree program. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 702 credit. S, U grading.

800 Doctoral Research, Dissertation, and/or Examination V 1-18 May be repeated for credit. Course Prerequisite: Admitted to the Biology, Plant Biology, Botany, or Zoology PhD program. Independent research and advanced study for students working on their doctoral research, dissertation and/or final examination. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 800 credit. S, U grading.


Courses with the BIOLOGY Subject

The online catalog includes the most recent changes to courses and degree requirements that have been approved by the Faculty Senate, including changes that are not yet effective. Courses showing two entries of the same number indicate that the course information is changing. The most recently approved version is shown first, followed by the older version, in gray, with its last-effective term preceding the course title. Courses shown in gray with only one entry of the course number are being discontinued. Course offerings by term can be accessed by clicking on the term links when viewing a specific campus catalog.

Biology (BIOLOGY)

101 [BSCI] Biology of Humans 3 The biology of good health and longevity evaluation of lifestyle choices consideration of each body system and the potential for disease and disorder. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

102 [BSCI] General Biology 4 (3-3) Enrollment not allowed if credit for BIOLOGY 105 already earned. Understanding current and future advances in biology as 'citizen scientists'. Lecture and laboratory not for students majoring in the life sciences. Credit not allowed for students who have already completed BIOLOGY 105. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

103 Science and Scientific Thinking 1 (0-3) Exploring science as a tool for understanding nature using case studies, experimentation, and data analysis. Topics range from atoms to ecosystems including physiology, inheritance, and the carbon cycle. Credit not granted towards elective requirements for majors in the School of Biological Sciences. Recommended for students with an ALEKS math placement score of less than 45%. (Crosslisted course offered as BIOLOGY 103, SCIENCE 103).

105 General Biology Laboratory 1 (0-3) Course Prerequisite: Junior standing. Enrollment not allowed if credit for BIOLOGY 102 already earned. Understanding biology as a science and its effect on issues within society. Laboratory only. Credit not allowed for students who have already completed BIOLOGY 102. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

106 [BSCI] Introductory Biology: Organismal Biology 4 (3-3) Course Prerequisite: One of the following -- a minimum ALEKS math placement score of 40%, MATH 100 with an S, MATH 101 with a C or better, MATH 103 or higher, BIOLOGY 103 with a C or better, BIOLOGY 102, BIOLOGY 120, or 3 credits of biology with a lab. One semester of a two semester sequence (BIOLOGY 106/107 or BIOLOGY 107/106) for science majors and pre-professional students. Biology of organisms plants, animals, ecology and evolution.

107 [BSCI] Introductory Biology: Cell Biology and Genetics 4 (3-3) Course Prerequisite: Minimum 2 credits 100 level CHEM or concurrent enrollment. First or second semester of a one-year sequence (BIOLOGY 106/107 or BIOLOGY 107/106) for science majors and pre-professional students. Cell biology and genetics of prokaryotes and eukaryotes.

110 Biological Perspectives on Environmental Issues 3 Current case studies of human interaction with the environment exploring concepts in ecology, biodiversity, global chemical cycles, and climate change. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

111 [BSCI] Laboratory Experiments in Biology and Genetics 1 (0-3) Scientific method and its application to a diverse range of biology and genetics topics and research questions. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

120 [BSCI] Introductory Botany 4 (3-3) Introduction to plant science, highlighting certain aspects of plant biology and current research and how these relate to us all in the modern world. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

125 Genetics and Society 3 Genetic topics in media and daily life including human health, agriculture, ecology and forensics for the educated non-biologist. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

135 Animal Natural History 3 Identification, life history, habitat relations, ecology, behavior, and conservation of animals commonly found in the Pacific Northwest. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

140 [BSCI] Introduction to Nutritional Science 3 Information related to dietary sources of nutrients, their functions in the body, physiologic and environmental factors that govern nutrient requirements, and guidelines for optimal dietary patterns. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

150 [BSCI] Evolution 3 Basic principles and implications of Darwinian evolution. Credit not granted towards elective requirements for majors in the School of Biological Sciences.

201 Contemporary Biology 1 Course Prerequisite: BIOLOGY 101, 102, 106, 107, 120, or MBIOS 101. Biological information that provides a framework for understanding life processes impact of biological information on human affairs.

210 Your Future in Life Sciences 2 Exploration of career options in biological sciences with faculty and outside speakers guide to preparing resume and career plans. (Crosslisted course offered as SCIENCE 210, BIOLOGY 210).

220 Medical Terminology 2 Course Prerequisite: BIOLOGY 101, 102, 106, 107, or KINES 262. Terms and word constructions for health care occupations format and function of medical records.

221 Exploring Health Careers 1 Introduction to human and animal health care careers. S, F grading.

225 Preparation for the Health Care Workplace 2 (1-3) Basic content and skills to prepare for health related internships.

251 Introductory Human Physiology 4 (3-3) Course Prerequisite: BIOLOGY 102, 106, or 107. Basic physiological processes in humans from the cellular to the organismal level. Credit not granted for both BIOLOGY 251 and 353.

298 [BSCI] Honors Biology for Non-Science Majors 4 (3-3) Course Prerequisite: Must be an Honors student. Understanding the natural world from a biological perspective for non-science majors.

301 General Genetics 4 Course Prerequisite: BIOLOGY 106 or 120 BIOLOGY 107 CHEM 101 or 105 CHEM 102 or 106. Principles of modern and classical genetics. (Crosslisted course offered as MBIOS 301, BIOLOGY 301).

307 [DIVR] Biology of Women 3 Course Prerequisite: BIOLOGY 102 or 106. Biological basis of sex and its relationship to body function, women and health care, and the impact of social and cultural perspectives on the experience of being female. (Crosslisted course offered as BIOLOGY 307, WOMEN ST 307).

308 [BSCI] Marine Biology 3 Course Prerequisite: BIOLOGY 106 sophomore standing. Introduction to the marine environment including oceanic, near-shore and estuarine communities of organisms and their roles and interactions.

315 Gross and Microanatomy 4 (3-3) Course Prerequisite: At least 3 hours of BIOLOGY sophomore standing cumulative WSU GPA 2.5 or better. Gross and microscopic anatomy of the human body. Recommended for pre-health care professionals only.

321 [M] Principles of Animal Development 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 107. Experimental analyses of development and descriptive and comparative examination of embryology emphasis on the chordates. Recommended preparation: BIOLOGY 301 or MBIOS 301.

322 [M] Invertebrate Biology 4 (3-3) Course Prerequisite: BIOLOGY 106. Phylogenetic relationships, development, and functional ecology of the invertebrate animals.

324 Comparative Vertebrate Anatomy 4 (2-6) Course Prerequisite: BIOLOGY 106. Evolution of vertebrates and their organ systems correlation of structural modification with function. Cooperative: Open to UI degree-seeking students.

330 Principles of Conservation 3 Course Prerequisite: BIOLOGY 102, 106, or 107. Conservation of major natural resources through a biological approach philosophical, economic, and political aspects of important conservation issues.

332 [M] Systematic Botany 4 (3-3) Course Prerequisite: BIOLOGY 106 or 120. Identification and classification of vascular plants with emphasis on the local flora.

333 [BSCI] Human Nutrition and Health 3 Course Prerequisite: BIOLOGY 102, 106, 107, 251, 315, or concurrent enrollment in BIOLOGY 251. Credit not granted for students who have already completed BIOLOGY 233 with a grade of C or above. Foundations in nutritional science and its relationship to human health through the application of fundamental principles of biology.

335 [M] Genome Biology 3 Course Prerequisite: BIOLOGY 301. Comparative analysis of genomes from bacteria to humans including methods for sequencing, genotyping, annotation of genomes, population genetics and evolution.

340 Introduction to Mathematical Biology 3 Course Prerequisite: MATH 140 with a C or better, or MATH 172 with a C or better, or MATH 182 with a C or better BIOLOGY 101, BIOLOGY 102, BIOLOGY 106, or BIOLOGY 107. Mathematical biology and development of mathematical modeling for solutions to problems in the life sciences. (Crosslisted course offered as MATH 340, BIOLOGY 340).

350 Comparative Physiology 4 (3-3) Course Prerequisite: BIOLOGY 107 CHEM 345. Analysis of systems and integrative physiology with an emphasis on evolutionary adaptation among mammalian and non-mammalian vertebrates.

352 Cells 3 Course Prerequisite: BIOLOGY 107 CHEM 345. Diversity and processes at the cellular level structure and function.

353 Advanced Human Physiology 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 107. Function and control at the organ-organismic level with emphasis on mammals, including humans emphasis on human health science applications. Credit not granted for both BIOLOGY 251 and 353. Recommended preparation: BIOLOGY 315 or 354.

354 Human Anatomy for Health Occupations 4 (3-3) Course Prerequisite: BIOLOGY 107 CHEM 102 or 345. History and anatomy of humans with non-cadaver-based laboratory utilizing preserved and histological specimens, models and software.

360 Molecular Processes of Living Organisms 3 Course Prerequisite: BIOLOGY 107. Exploration of fundamental molecular processes to encourage thinking beyond biological species in order to comprehend larger-scale biological issues and relevance for society.

370 [M] Ecology of Health and Disease 4 (3-3) Course Prerequisite: BIOLOGY 106 CHEM 102 or 105. Enrollment in BIOLOGY 370 not allowed if credit already earned for BIOLOGY 372. Ecology of species interactions in changing environments and how they influence human and animal health. Credit not granted for both BIOLOGY 370 and 372. Field trips may be required.

372 [M] General Ecology 4 (3-3) Course Prerequisite: BIOLOGY 106 CHEM 102 or 105. Enrollment in BIOLOGY 372 not allowed if credit already earned for BIOLOGY 370. Relationship of organisms with physical and biotic components of their environment at the population, community, and ecosystem level. Credit not granted for both BIOLOGY 370 and 372. Field trips may be required.

390 Stream Monitoring 1 (0-3) Course Prerequisite: BIOLOGY 101, 102, or 106 CHEM 101 or 105 junior standing. Principles and methods of water quality monitoring, including habitat assessment, water chemistry, and biological assessment. Field work and independent research required.

393 [M] Professional Communications in Biology 2 Course Prerequisite: Admitted to the major in Biology or Zoology. Literature investigation, oral presentation and written reports of selected topics in biology.

394 Medicine as a Career 2 Course Prerequisite: Junior standing. Current issues in medicine ethical, financial, and personal aspects of medical practice. S, F grading.

395 Evolutionary Medicine 3 Course Prerequisite: BIOLOGY 301. Modern medical issues from an evolutionary perspective, integrated with other biological fields in medical research topics include disease diversity, immune function, the evolution of virulence, human disease management, cancer, obesity, and human mental and reproductive health issues and their management.

401 [CAPS] Plants and People 3 Course Prerequisite: BIOLOGY 106 or 120 BIOLOGY 107 junior standing. Relationships between plants and people, especially cultural and economic applications of plants.

402 [M] Beneficial Microbes in Nature and Society 3 Course Prerequisite: BIOLOGY 372, 403, or 405 junior standing. In-depth investigations of interdisciplinary topics addressing the importance of beneficial microbes to organisms, natural systems, and society from across the disciplines of microbiology, medicine, evolutionary ecology, and agricultural science.

403 Evolutionary Biology 3 Course Prerequisite: BIOLOGY 301. The survey of evidence for evolution and operation of evolutionary processes that influence adaptation, diversification and speciation in organisms.

405 Principles of Organic Evolution 3 (2-3) Course Prerequisite: BIOLOGY 301. The evolutionary processes that influence adaptation, population differentiation, and speciation in organisms.

408 [CAPS] [M] Contemporary Genetics 3 Course Prerequisite: MBIOS / BIOLOGY 301 with a C or better junior standing. Consideration of the state-of-the-art genetic technologies and their impact on society, environment and the economy.

409 Plant Anatomy 4 (2-6) Course Prerequisite: BIOLOGY 106 or 120. Developmental anatomy and morphology of vascular plants economic forms. Credit not granted for both BIOLOGY 409 and BIOLOGY 509. Offered at 400 and 500 level.

410 Marine Ecology 3 Course Prerequisite: BIOLOGY 106. The ecology and conservation of marine organisms, communities, and ecosystems.

412 Biology of Fishes 3 (2-3) Course Prerequisite: BIOLOGY 106. Evolution, identification, life history, and characteristics of important fish species.

418 Parasitology 4 (3-3) Course Prerequisite: BIOLOGY 102 or BIOLOGY 106 junior standing. Types of associations, life cycles, control, prevention, and modifications of parasites examination of parasitic protozoa and helminths.

420 Plant Physiology 3 Course Prerequisite: BIOLOGY 106 or 120. Water relations, mineral nutrition, photosynthesis, respiration, and growth of plants. Recommended: Organic chemistry.

421 Plant Physiology Laboratory 1 (0-3) Course Prerequisite: BIOLOGY 420 or concurrent enrollment. Laboratory for Biol 420.

423 Ornithology 4 (3-3) Course Prerequisite: BIOLOGY 106. Ecology, systematics, and evolution of birds. Field trips required include two Saturdays.

428 Mammalogy 4 (3-3) Course Prerequisite: BIOLOGY 106. Ecology, systematics, and evolution of mammals.

430 Methods of Teaching Secondary Science I 3 Course Prerequisite: Junior standing. Application of learning and theory and philosophy and structure of science in teaching middle and secondary school science courses. (Crosslisted course offered as BIOLOGY 430, MBIOS 480, TCH LRN 430).

431 Methods of Teaching Secondary Science II 3 Course Prerequisite: BIOLOGY 430, MBIOS 480, or TCH LRN 430 junior standing. Integration of assessment, curricular, and technological tools into instruction that aligns with learning theory and the philosophy/structure of science. (Crosslisted course offered as BIOLOGY 431, MBIOS 481, TCH LRN 431).

432 [M] Biology of Amphibians and Reptiles 4 (3-3) Course Prerequisite: BIOLOGY 106 BIOLOGY 372 or SOE 300. Characteristics, evolution, and systematics patterns of distribution adaptive strategies interactions between humans and amphibians and reptiles.

438 [M] Animal Behavior 3 (2-3) Course Prerequisite: BIOLOGY 106. Biological study of animal behavior as viewed from ethological, genetic, developmental, ecological, and evolutionary perspectives.

446 Mutualism and Symbiosis 3 Course Prerequisite: BIOLOGY 372, 403, or 405. Critical evaluation of the ecology, evolution, and molecular biology of mutualism and symbiosis. Credit not granted for both BIOLOGY 446 and 546. Offered at 400 and 500 level.

456 Neuroethology 3 Course Prerequisite: BIOLOGY 301, MBIOS 303, or 300-level NEUROSCI course STAT 412 or concurrent enrollment. Introduction to neural mechanisms underlying natural animal behaviors from the cellular level to the organismal level.

462 Community Ecology 3 Course Prerequisite: BIOLOGY 372 with a C or better. Assembly, essential properties, levels of interactions, succession, and stability of natural communities emphasizes an experimental approach to community investigation. Credit not granted for both BIOLOGY 462 and BIOLOGY 562. Recommended preparation: BIOLOGY 372. Offered at 400 and 500 level.

465 Field Stream Ecology 2 Course Prerequisite: BIOLOGY 372. Ecological roles of immature insects in different size streams pattern changes along the stream continuum other ecological characteristics.

469 [M] Ecosystem Ecology and Global Change 3 Historic and current factors controlling the function of ecosystems and their responses to natural and human caused global change. Credit not granted for both BIOLOGY 469 and 569. Offered at 400 and 500 level. Cooperative: Open to UI degree-seeking students.

470 Diversity of Plants 3 Morphological, life history, and ecological diversity of major plant clades emphasis on principles of homology, character transformation, and macroevolution.

473 [CAPS] [M] Evolution and Society 3 Course Prerequisite: ANTH 260 or BIOLOGY 301 junior standing. Survey of how the theory of evolution is used to better understand ourselves, the societies in which live, and the biological world on which we depend. Recommended preparation: BIOLOGY 405 or concurrent enrollment. (Crosslisted course offered as BIOLOGY 473, ANTH 473).

474 Computational Biology 4 (3-3) Course Prerequisite: BIOLOGY 301 MATH 140 or 171 STAT 212, 412, or PSYCH 311. Theory and current literature on a wide range of computational techniques used to address and solve problems in biology a practical introduction to R/python as scientific languages useful in the solution of problems in biology.

475 Systems Biology of Reproduction 3 Current literature based course on systems biology with a molecular/epigenetic to physiological level understanding of cell, development, disease, and evolutionary biology. Credit not granted for both BIOLOGY 475 and 575. Offered at 400 and 500 level.

476 Epigenetics and Systems Biology 3 Course Prerequisite: BIOLOGY 301. Current literature based course on epigenetics and systems biology with topics in environmental epigenetics, disease etiology, and role epigenetics in evolutionary biology. Credit not granted for both BIOLOGY 476 and 576. Offered at 400 and 500 level.

480 [M] Writing in Biology 2 Course Prerequisite: Admitted to the major in Biology or Zoology. Discussion and practice in relating thinking and writing popular and professional communication in biology.

483 [CAPS] [M] Organisms and Global Change 3 Course Prerequisite: BIOLOGY 372 junior standing. Interaction between organisms and global change across scales of biology.

485 [CAPS] Biology of the Oceans 3 Course Prerequisite: BIOLOGY 106 junior standing. Interdisciplinary capstone course that explores the ocean world from molecules to ecosystems in the context of scientific discovery and society.

486 [M] Marine Invertebrate Communities 3 (2-3) Course Prerequisite: BIOLOGY 106. Survey of marine invertebrates and their habitats. One-week field/lab course at a marine station.

489 [CAPS] [M] Synthesis and Communication of Independent Research 3 Course Prerequisite: 2 credits BIOLOGY 499 admitted to major in Biology or Zoology junior standing by permission only. Integration of broad topics from biology and other science fields to inform scientific writing and presentation of independent research projects.

490 [M] Professional Seminar in Physical Therapy 2 Course Prerequisite: By permission only. Consideration of treatment modalities and health issues in physical therapy and related disciplines. A, S, F grading.

491 Clinical Experience V 1-4 May be repeated for credit cumulative maximum 20 hours. Course Prerequisite: PSYCH 105 BIOLOGY 315 junior standing by permission only. Work experience under supervision of a qualified professional in a clinical setting. S, F grading.

492 Topics in Biology V 1-3 May be repeated for credit cumulative maximum 6 hours.

494 Seminar in Mathematical Biology 1 May be repeated for credit cumulative maximum 4 hours. Course Prerequisite: MATH 140 with a C or better, or MATH 172 with a C or better, or MATH 182 with a C or better BIOLOGY 101, BIOLOGY 102, BIOLOGY 106, or BIOLOGY 107. Oral presentation of research approaches, research results and literature review of mathematical biology including mathematical modeling of biological systems. (Crosslisted course offered as MATH 494, BIOLOGY 494). Cooperative: Open to UI degree-seeking students. S, F grading.

495 Internship in Biology, Botany, and Zoology V 1-4 May be repeated for credit cumulative maximum 8 hours. Course Prerequisite: By permission only. Experience in work related to specific career interests. S, F grading.

496 [M] Special Problems and Reports V 1-4 Course Prerequisite: By permission only. Independent project with written project proposal, progress report, and final report required. S, F grading.

497 Instructional Practicum V 1-4 May be repeated for credit cumulative maximum 8 hours. Academic traineeship in laboratory teaching and tutoring.

499 Special Problems V 1-4 May be repeated for credit. Course Prerequisite: By permission only. Independent study conducted under the jurisdiction of an approving faculty member may include independent research studies in technical or specialized problems selection and analysis of specified readings development of a creative project or field experiences. S, F grading.

500 Seminar 1 May be repeated for credit. S, F grading.

501 Proposal Defense Seminar 2 Research proposal defense as part of the preliminary examination for candidacy in the Ph.D. program. S, F grading.

504 Experimental Methods in Plant Physiology 4 (2-6) Advanced techniques and instrumental methods applicable to research in plant physiology.

509 Plant Anatomy 4 (2-6) Developmental anatomy and morphology of vascular plants economic forms. Credit not granted for both BIOLOGY 409 and BIOLOGY 509. Offered at 400 and 500 level.

512 Molecular Mechanisms of Plant Development 3 Physiology of growth metabolism during development and reproduction.

513 Plant Metabolism 3 Metabolic processes unique to plants, including the primary incorporation of nitrogen, sulfur, carbon dioxide and phosphate into bio-molecules.

514 Fish Genetics 2 Chromosomal, biochemical, quantitative, and ecological aspects of fish genetics with emphasis on applications to aquaculture and fish management. Cooperative: Open to UI degree-seeking students.

517 Stress Physiology of Plants 3 Temperature, light, salinity, water effects on physiological processes mechanistic understanding of stress.

519 Introduction to Population Genetics 3 Survey of basic population and quantitative genetics. Cooperative: Open to UI degree-seeking students.

520 Conservation Genetics 2 Genetic studies and approaches relevant to efforts to conserve threatened and endangered populations of organisms.

521 Quantitative Genetics 3 Course Prerequisite: BIOLOGY 519. Fundamentals of quantitative genetics evolutionary quantitative genetics. Cooperative: Open to UI degree-seeking students.

531 Principles of Systematic Biology 3 Systematic theory history and current views approaches to phylogenetic analysis and classification.

533 Modern Methods in Phylogenetics 4 (2-6) Selecting, gathering, and analyzing morphological, cytological, molecular data for phylogenetic and evolutionary studies.

534 Modern Methods in Population Genomics 3 Course Prerequisite: BIOLOGY 519. Problems and prospects of designing a study with genomic data: from raw data to demography and selection inferences.

537 Plant Cell Biology 3 Structure and function of plant cells including membrane biology, protein targeting and molecular signaling with emphasis on current research.

540 Stable Isotope Theory and Methods 3 Theory and practice of measuring stable isotope ratios of biologically important elements. Cooperative: Open to UI degree-seeking students.

544 Nitrogen Cycling in the Earth's Systems 3 Nitrogen dynamics in terrestrial, aquatic, and atmospheric systems nitrogen transformations in natural and managed systems and responses to human activities. (Crosslisted course offered as BIOLOGY 544, SOIL SCI 544).

545 Statistical Genomics 3 (2-3) Develop concepts and analytical skills for modern breeding by using Genome-Wide Association Study and genomic prediction in framework of mixed linear models and Bayesian approaches. (Crosslisted course offered as CROP SCI 545, ANIM SCI 545, BIOLOGY 545, HORT 545, PL P 545.) Recommended preparation: BIOLOGY 474 MBIOS 478. Cooperative: Open to UI degree-seeking students.

546 Mutualism and Symbiosis 3 Critical evaluation of the ecology, evolution, and molecular biology of mutualism and symbiosis. Credit not granted for both BIOLOGY 446 and 546. Offered at 400 and 500 level.

548 Evolutionary Ecology of Populations 3 Evolutionary dynamics of natural populations and the co-evolution of species. Cooperative: Open to UI degree-seeking students.

549 Behavioral Ecology 3 Examination of animal behavior from evolutionary and ecological perspectives.

556 Biochemical Adaptation 3 Relationships between enzyme/macromolecule adaptation and animal performance.

559 Hormones, Brain and Behavior 3 Classical behavioral endocrinology from molecular to whole organisms, integrating evolutionary ecology, neuroethology and behavioral neuroendocrinology.

560 Plant Ecophysiology 3 Relationships of biotic and abiotic environment to plant distribution and evolution through study of physiological processes.

561 Environmental Physiology 3 Individual and evolutionary adaptations to changing environments with emphasis on recent literature.

562 Community Ecology 3 Assembly, essential properties, levels of interactions, succession, and stability of natural communities emphasizes an experimental approach to community investigation. Credit not granted for both BIOLOGY 462 and BIOLOGY 562. Recommended preparation: BIOLOGY 372. Offered at 400 and 500 level.

563 Field Ecology 2 (0-6) Field implementation of descriptive and experimental techniques to quantify the structure, composition, and interactions within natural communities. Field trips required. Cooperative: Open to UI degree-seeking students.

564 Molecular Ecology and Phylogeography 3 Use of genetic markers for the study of ecological phenomena, including kinship, population structure, and phylogeography. Cooperative: Open to UI degree-seeking students.

565 Ecology and Evolution of Disease 3 Disease ecology and evolution with a focus on current literature. Recommended preparation: BIOLOGY 372 BIOLOGY 405. Cooperative: Open to UI degree-seeking students.

566 Mathematical Genetics 3 Mathematical approaches to population genetics and genome analysis theories and statistical analyses of genetic parameters. (Crosslisted course offered as MATH 563, BIOLOGY 566). Required preparation must include multivariate calculus, genetics, and statistics. Cooperative: Open to UI degree-seeking students.

567 Ecological Restoration 3 Introduction to major issues in restoration ecology major ecological dimensions of restoration.

568 Conservation Ecology 3 Diagnosis of endangered species, population viability analysis, invasive species ecology, landscape ecology and ecosystem management.

569 [M] Ecosystem Ecology and Global Change 3 Historic and current factors controlling the function of ecosystems and their responses to natural and human caused global change. Credit not granted for both BIOLOGY 469 and 569. Offered at 400 and 500 level. Cooperative: Open to UI degree-seeking students.

570 Diversity of Plants 3 Morphological, life history, and ecological diversity of major plant clades emphasis on principles of homology, character transformation, and macroevolution.

571 Quantitative Toolkit for Biologists 3 Course Prerequisite: STAT 512. Hands-on experience in the exploration, analysis, and interpretation of patterns in modern biological datasets.

572 Quantitative Methods and Statistics in Ecology 4 (3-3) Course Prerequisite: By permission only. Philosophy and methods of formulating hypotheses as mathematical models and confronting them with data.

573 Ancient DNA 3 The prospects and problems associated with the study of ancient DNA are explored through reading and discussing primary literature.

575 Systems Biology of Reproduction 3 Current literature based course on systems biology with a molecular/epigenetic to physiological level understanding of cell, development, disease, and evolutionary biology. Credit not granted for both BIOLOGY 475 and 575. Offered at 400 and 500 level.

576 Epigenetics and Systems Biology 3 Current literature based course on epigenetics and systems biology with topics in environmental epigenetics, disease etiology, and role epigenetics in evolutionary biology. Credit not granted for both BIOLOGY 476 and 576. Offered at 400 and 500 level.

579 Mathematical Modeling in the Biological and Health Sciences 3 Techniques, theory, and current literature in mathematical modeling in the biological and health sciences, including computational simulation. (Course offered as BIOLOGY 579, MATH 579). Cooperative: Open to UI degree-seeking students.

581 Comparative Biology of Social Traditions 3 Phylogenetic and modeling perspectives used to examine the evolution of social learning and cultural transmission in humans and other animals. (Crosslisted course offered as ANTH 581, BIOLOGY 581).

582 Professional Communication in Biology - Grant Writing 2 Mechanics and style of publishing biological research and findings adaptation of writing to various venues and audiences with emphasis on grant writing.

585 Professional Development and Training for College and University Teaching 2 Preparation for roles as teaching assistants and as instructors of undergraduate classroom education.

589 Advanced Topics in Biology V 1-3 May be repeated for credit cumulative maximum 6 hours. Recent advances in biology.

591 Seminar in Molecular Plant Sciences 1 May be repeated for credit cumulative maximum 4 hours. A cross-discipline seminar, including botany, crop and soils sciences, horticulture, plant pathology, and molecular plant sciences.

593 Seminar I 1 May be repeated for credit. Literature and problems.

597 Teaching Practicum V 1-4 May be repeated for credit cumulative maximum 4 hours. Zoology laboratory teaching internship. S, F grading.

600 Special Projects or Independent Study V 1-18 May be repeated for credit. Independent study, special projects, and/or internships. Students must have graduate degree-seeking status and should check with their major advisor before enrolling in 600 credit, which cannot be used toward the core graded credits required for a graduate degree. S, F grading.

700 Master's Research, Thesis, and/or Examination V 1-18 May be repeated for credit. Independent research and advanced study for students working on their master's research, thesis and/or final examination. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 700 credit. S, U grading.

702 Master's Special Problems, Directed Study and/or Examination V 1-18 May be repeated for credit. Independent research in special problems, directed study, and/or examination credit for students in a non-thesis master's degree program. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 702 credit. S, U grading.

800 Doctoral Research, Dissertation, and/or Examination V 1-18 May be repeated for credit. Course Prerequisite: Admitted to the Biology, Plant Biology, Botany, or Zoology PhD program. Independent research and advanced study for students working on their doctoral research, dissertation and/or final examination. Students must have graduate degree-seeking status and should check with their major advisor/committee chair before enrolling for 800 credit. S, U grading.


General Overviews

Facilitation is a subset of the possible interactions associated with the organization of community, ranging from positive, to neutral, to negative. Hence, facilitation, in the broadest sense, is often included in many works describing plant communities. There are several excellent overviews, both books and peer-reviewed articles, that formally discuss facilitation and that are ideal launching points for further reading. Callaway 1995 is the classic and the first review that promoted the term facilitation. A more comprehensive treatise on the subject by Callaway followed that original paper (Callaway 2007). Although the general focus and theme are implicitly community based, this book focuses more directly on facilitation itself, with chapters on direct and indirect mechanisms of facilitation, interactions with competition, and species specificity. The final chapter is, however, on community organization. A second book on this topic, written by a subset of the leaders of the field, including Callaway, and edited by Pugnaire, was published in the following year (Pugnaire 2010). This book is explicitly focused on the community, with chapters on indices, diversity, biodiversity, mycorrhizae, climate change, and stress gradients, and less directly on the specifics of facilitation. Callaway 2007 is the most thorough reader available on plant facilitation and addresses virtually every aspect of its study, whereas the latter text is a broader and more diverse treatment of facilitation, as it relates to community ecology. Two overviews on facilitation have also been published in the Journal of Ecology and another, in Biology Letters. The first Journal of Ecology paper (Brooker, et al. 2008) articulates previous research and illuminates future directions whereas the second (Brooker and Callaway 2009) introduces a special section on a symposium on facilitation held at the University of Aberdeen, Scotland, from 20 to 22 April 2009. The final overview, in Biology Letters (Pakeman, et al. 2009), also discusses this symposium and describes the conceptual status of facilitation in the early 21st century, including future directions.

Brooker, Rob W., and Ragan M. Callaway. 2009. Facilitation in the conceptual melting pot. Journal of Ecology 97.6: 1117–1120.

This is a short, synthetic piece that offers a clear overview of the broad significance of facilitation research and its importance to theory.

Brooker, Rob W., Fernando T. Maestre, Ragan M. Callaway, et al. 2008. Facilitation in plant communities: The past, the present, and the future. Journal of Ecology 96.1: 18–34.

This is a highly cited paper for future directions and clearly describes the advances and key developments from the published empirical work. The first table provided is an excellent resource for quick identification of readings associated with seminal works. As an excellent, comprehensive starting point that is a single, short read, this is likely the best place to begin for an overview—particularly for future directions.

Callaway, Ragan M. 1995. Positive interactions among plants. Botanical Review 61.4: 306–349.

Callaway thoroughly examines all the literature published up to that time on most aspects of facilitation. This paper is a perfect starting point for assessing the biology and biological mechanisms associated with positive interactions in plants. As a seminal citation on facilitation, this publication is extremely useful. Also, the paper is an excellent source for the critical physiological studies that underpin modern facilitation research. Available online for purchase or by subscription.

Callaway, Ragan M. 2007. Positive interactions and interdependence in plant communities. Dordrecht, The Netherlands: Springer.

This book provides the reader with a comprehensive treatment of direct versus indirect mechanisms of facilitation and examination of the evidence for whether positive effects are species specific. Every aspect of facilitation is covered in detail, and if the reader is interested in mechanisms, this is the best source for a full understanding of the scope of effects studied in plant facilitation experiments.

This is a short and accessible essay on the status of facilitation in the early 21st century, in terms of conceptual refinement, evolution, community-level effects, and restoration, and on future directions in general for the field. This is likely the quickest read on the topic, serving as a brief and broad overview. Topical issues are identified and future directions, explained.

Pugnaire, Francisco I., ed. 2010. Positive plant interactions and community dynamics. Boca Raton, FL: CRC.

A collection of essays focused on facilitation and the plant community. This is not so much a book about the biology of facilitations as one on the derived or advanced aspects of facilitation, in that it addresses implications at the community level. This source is an excellent community ecology book mainly focused on positive plant interactions, with less detail than Callaway 2007 but with more focus on the community. A logical pipeline for the reader would be to begin with Callaway 2007, for an understanding of the mechanisms, and then move on to this book for community-level implications.

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Parasite- host interactions

Parasites and their hosts engage in a similar evolutionary arms race, although in the past parasitologists believed this not to be the case. Instead, parasites were thought to evolve gradually toward reduced antagonism—having a less detrimental effect on their hosts. The degree of virulence was sometimes regarded as an indicator of the age of the relationship: a very virulent relationship, which resulted in the swift demise of the host, was considered new. Research in population biology and evolutionary ecology, however, provided evidence that contradicts this view. Parasite-host interactions are now understood to evolve toward either increased or decreased antagonism, depending on several important ecological factors.

The density of the host population and the transmission rate of the parasite are two of the most important of these ecological factors. The density of the host species determines how often the opportunity arises for a parasite to move from one host to another the transmission rate of the parasite determines how easily a parasite can move between hosts when the opportunity does arise. Only some parasites are transmitted easily between hosts. If the host occurs at a high density and the transmission rate of the parasite is also high, then natural selection favours increased virulence in the parasite. Being easily transmissible and having many host individuals to infect, the parasite can multiply quickly and escape to new hosts before it kills its current host and dies along with it. Some forms (genotypes) of the parasite will already contain or will develop mutations that increase the speed and proficiency of this process. By producing more organisms that survive, the mutated form of the parasite will outcompete those parasites with the original genotype that are not able to maximize the opportunity to infect the greatest number of hosts. After several generations, many more parasites with enhanced virulence will exist, and this genotype can be said to be favoured by natural selection. If host population density remains high, the parasite genotype that confers the most virulence will become the only form of the parasite in that population.

At the other extreme, if the host population density is low and the transmission rate of the parasite is also low, natural selection will favour less virulent forms of the parasite. The highly virulent forms that quickly kill their host will often die along with their host without having spread to other hosts, leaving only the less virulent parasites to propagate the species.

In many natural environments, host populations fluctuate between high and low density. Consequently, the parasite population will fluctuate as well, sometimes containing more highly virulent forms, sometimes less virulent forms. Depending on the rate at which host density fluctuates, the host population will vary in the degree and mix of virulent forms that it harbours.

The evolution of myxoma virus in rabbits in Australia shows how quickly coevolution of parasites and hosts can proceed to a new outcome, in this case intermediate virulence. European rabbits were introduced into Australia in the 1800s. In the absence of parasites and predators that had kept their numbers in check in their European habitat, they multiplied and disseminated rapidly, causing widespread destruction of the native vegetation. When the myxoma virus was introduced into Australia in 1950 to control rabbit populations, it was highly virulent and caused death in almost all infected rabbits within two weeks. Since then, however, coevolution of the virus and rabbit populations has occurred, resulting in an interaction less immediately lethal to the rabbits. As population levels of the rabbits decreased, mutant strains of the virus that allowed a rabbit host to live longer were favoured, thereby increasing the opportunity for the virus to spread to another rabbit before its current host died. Most infected rabbits still die from the infection, but death is not as relentless and most infected individuals survive for two and a half to four weeks after infection.


Chapter 47- Community Ecology

Camouflage (cryptic coloration) - blending in
Mimicry - one species resembles another as a defense (milk snake)

Herding Behavior (zebra)
Startle Behavior (blowfish)
Anatomical defense (porcupine)
Chemical defense (skunk)

Symbiotic relationships

Symbiosis - intimate relationship between two or more species

Parasitism - one individual is harmed, the other benefits (ticks & deer)
Mutualism - both benefit (flowers & honeybees)
Commensalism - one benefits, other is neither harmed or benefited (clown fish & sea anemone)


Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.

References

. 2002 Trophic strategies, animal diversity and body size . Trends Ecol. Evol. 17, 507-513. (doi:10.1016/S0169-5347(02)02615-0) Crossref, ISI, Google Scholar

Raffel TR, Martin LB, Rohr JR

. 2008 Parasites as predators: unifying natural enemy ecology . Trends Ecol. Evol. 23, 610-618. (doi:10.1016/j.tree.2008.06.015) Crossref, PubMed, ISI, Google Scholar

. 2020 An integrated landscape of fear and disgust: the evolution of avoidance behaviors amidst a myriad of natural enemies . Front. Ecol. Evol. 8, 317. (doi:10.3389/fevo.2020.564343) Crossref, ISI, Google Scholar

Preisser EL, Bolnick DI, Benard MF

. 2005 Scared to death? The effects of intimidation and consumption in predator–prey interactions . Ecology 86, 501-509. (doi:10.1890/04-0719) Crossref, ISI, Google Scholar

Sheriff MJ, Peacor SD, Hawlena D, Thaker M

. 2020 Non-consumptive predator effects on prey population size: a dearth of evidence . J. Anim. Ecol. 89, 1302-1316. (doi:10.1111/1365-2656.13213) Crossref, PubMed, ISI, Google Scholar

Weinstein SB, Buck JC, Young HS

. 2018 A landscape of disgust . Science 359, 1213-1214. (doi:10.1126/science.aas8694) Crossref, PubMed, ISI, Google Scholar

Buck JC, Weinstein SB, Young HS

. 2018 Ecological and evolutionary consequences of parasite avoidance . Trends Ecol. Evol. 33, 619-632. (doi:10.1016/j.tree.2018.05.001) Crossref, PubMed, ISI, Google Scholar

Behringer DC, Butler MJ, Shields JD

. 2006 Avoidance of disease by social lobsters . Nature 441, 421. (doi:10.1038/441421a) Crossref, PubMed, ISI, Google Scholar

Butler MJ, Behringer DC, Dolan TW, Moss J, Shields JD

. 2015 Behavioral immunity suppresses an epizootic in Caribbean spiny lobsters . PLoS ONE 10, e0126374. (doi:10.1371/journal.pone.0126374) Crossref, PubMed, ISI, Google Scholar

. 2020 COVID-19 lockdown allows researchers to quantify the effects of human activity on wildlife . Nat. Ecol. Evol. 4, 1156-1159. (doi:10.1038/s41559-020-1237-z) Crossref, PubMed, ISI, Google Scholar

. 2020 What share of the world population is already on COVID-19 lockdown? Statista . See https://www.statista.com/chart/21240/enforced-covid-19-lockdowns-by-people-affected-per-country/ (accessed on 31 July 2020). Google Scholar

. 2020 The effect of large-scale anti-contagion policies on the COVID-19 pandemic . Nature 584, 262-267. (doi:10.1038/s41586-020-2404-8) Crossref, PubMed, ISI, Google Scholar

. 2020 Estimating the effects of non-pharmaceutical interventions on COVID-19 in Europe . Nature 584, 257-261. (doi:10.1038/s41586-020-2405-7) Crossref, PubMed, ISI, Google Scholar

. 2020 Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures . Science 369, 1338-1343. (doi:10.1126/science.abd2438) Crossref, PubMed, ISI, Google Scholar

. 2020 Temporary reduction in daily global CO2 emissions during the COVID-19 forced confinement . Nat. Clim. Change 10, 647-653. (doi:10.1038/s41558-020-0797-x) Crossref, ISI, Google Scholar

Peacor SD, Barton BT, Kimbro DL, Sih A, Sheriff MJ

. 2020 A framework and standardized terminology to facilitate the study of predation-risk effects . Ecology , e03152. (doi:10.1002/ecy.3152) PubMed, ISI, Google Scholar

. 2020 Ecology and economics for pandemic prevention . Science 369, 379-381. (doi:10.1126/science.abc3189) PubMed, ISI, Google Scholar

. 2020 Mental health and the COVID-19 pandemic . N. Engl. J. Med. 383, 510-512. (doi:10.1056/NEJMp2008017) Crossref, PubMed, ISI, Google Scholar

Matoori S, Khurana B, Balcom MC, Koh D-M, Froehlich JM, Janssen S, Kolokythas O, Gutzeit A

. 2020 Intimate partner violence crisis in the COVID-19 pandemic: how can radiologists make a difference? Eur. Radiol. 30, 6933-6936. (doi:10.1007/s00330-020-07043-w) Crossref, PubMed, ISI, Google Scholar

. 2020 The impact of the COVID-19 pandemic on suicide rates . QJM Int. J. Med. 113, 707-712. (doi:10.1093/qjmed/hcaa202) Crossref, ISI, Google Scholar

. 2020 I'm one of the thousands of extra cancer deaths we'll see this year. The Guardian. See http://www.theguardian.com/commentisfree/2020/jul/16/extra-cancer-deaths-this-year-covid19-nhs-health (accessed on 30 September 2020). Google Scholar

. 2020 Impact of the COVID-19 pandemic on emergency department visits—United States, January 1, 2019–May 30, 2020 . MMWR Morb. Mortal. Wkly. Rep. 69, 699-704. (doi:10.15585/mmwr.mm6923e1) Crossref, PubMed, ISI, Google Scholar

. 2010 The fertility effect of catastrophe: U.S. hurricane births . J. Popul. Econ. 23, 1-36. (doi:10.1007/s00148-008-0219-2) Crossref, ISI, Google Scholar

. 2014 Power outages, power externalities, and baby booms . Demography 51, 1477-1500. (doi:10.1007/s13524-014-0316-7) Crossref, PubMed, ISI, Google Scholar

2020 Coronavirus sex ban in Britain has people frolicking and the government mocked . Forbes . See https://www.forbes.com/sites/ceciliarodriguez/2020/06/04/sex-ban-in-britain-has-people-frolicking/ (accessed on 18 August 2020). Google Scholar

. 2003 A review of trait-mediated indirect interactions in ecological communities . Ecology 84, 1083-1100. (doi:10.1890/0012-9658(2003)084[1083:AROTII]2.0.CO2) Crossref, ISI, Google Scholar

Schmitz OJ, Grabowski JH, Peckarsky BL, Preisser EL, Trussell GC, Vonesh JR

. 2008 From individuals to ecosystem function: toward an integration of evolutionary and ecosystem ecology . Ecology 89, 2436-2445. (doi:10.1890/07-1030.1) Crossref, PubMed, ISI, Google Scholar

. 2004 Wolves and the ecology of fear: can predation risk structure ecosystems? BioScience 54, 755-766. (doi:10.1641/0006-3568(2004)054[0755:WATEOF]2.0.CO2) Crossref, ISI, Google Scholar

Philpott SM, Maldonado J, Vandermeer J, Perfecto I

. 2004 Taking trophic cascades up a level: behaviorally-modified effects of phorid flies on ants and ant prey in coffee agroecosystems . Oikos 105, 141-147. (doi:10.1111/j.0030-1299.2004.12889.x) Crossref, ISI, Google Scholar

. 2011 Cascading indirect effects in a coffee agroecosystem: effects of parasitic phorid flies on ants and the coffee berry borer in a high-shade and low-shade habitat . Environ. Entomol. 40, 581-588. (doi:10.1603/EN11015) Crossref, PubMed, ISI, Google Scholar

Mehdiabadi NJ, Kawazoe EA, Gilbert LE

. 2004 Phorid fly parasitoids of invasive fire ants indirectly improve the competitive ability of a native ant . Ecol. Entomol. 29, 621-627. (doi:10.1111/j.0307-6946.2004.00636.x) Crossref, ISI, Google Scholar

. 2013 Synergistic effects of predators and trematode parasites on larval green frog (Rana clamitans) survival . Ecology 94, 2697-2708. (doi:10.1890/13-0396.1) Crossref, PubMed, ISI, Google Scholar

. In press. Mussel shutdown: does the fear of parasites regulate the functioning of filter feeders in coastal ecosystems? Front. Ecol. Evol. (doi:10.3389/fevo.2020.569319) Google Scholar

Nguyen T, Saleh M, Kyaw M-K, Trujillo G, Bejarano M, Tapia K, Interns REC

. 2020 Lockdowns could be the ‘biggest conservation action’ in a century. The Atlantic. See https://www.theatlantic.com/science/archive/2020/07/pandemic-roadkill/613852/ (accessed on 16 July 2020). Google Scholar

. 2020 Impact assessment of non-pharmaceutical interventions against coronavirus disease 2019 and influenza in Hong Kong: an observational study . Lancet Public Health 5, e279-e288. (doi:10.1016/S2468-2667(20)30090-6) Crossref, PubMed, ISI, Google Scholar

Noh JY, Seong H, Yoon JG, Song JY, Cheong HJ, Kim WJ

. 2020 Social distancing against COVID-19: implication for the control of influenza . J. Korean Med. Sci. 35, e182. (doi:10.3346/jkms.2020.35.e182) Crossref, PubMed, ISI, Google Scholar

. 2020 How will COVID-19 affect the coming flu season? Scientists struggle for clues . Sci. AAAS. See https://www.sciencemag.org/news/2020/08/how-will-covid-19-affect-coming-flu-season-scientists-struggle-clues (accessed on 18 August 2020). Google Scholar

. 2020 The impact of COVID-19 on air pollution: evidence from global data . SSRN. See https://ssrn.com/abstract=3644198. (doi:10.2139/ssrn.3644198) Google Scholar

Gillingham KT, Knittel CR, Li J, Ovaere M, Reguant M

. 2020 The short-run and long-run effects of COVID-19 on energy and the environment . Joule 4, 1337-1341. (doi:10.1016/j.joule.2020.06.010) Crossref, PubMed, ISI, Google Scholar

. 2020 Influence of the COVID-19 crisis on global PM2.5 concentration and related health impacts . Sustainability 12, 5297. (doi:10.3390/su12135297) Crossref, ISI, Google Scholar

Buck JC, Weinstein SB, Titcomb G, Young HS

. 2020 Conservation implications of disease control . Front. Ecol. Environ. 18, 329-334. (doi:10.1002/fee.2215) Crossref, ISI, Google Scholar

Horrigan L, Lawrence RS, Walker P

. 2002 How sustainable agriculture can address the environmental and human health harms of industrial agriculture . Environ. Health Perspect. 110, 445-456. (doi:10.1289/ehp.02110445) Crossref, PubMed, ISI, Google Scholar

Servick K, Cho A, Guglielmi G, Vogel G, Couzin-Frankel J

. 2020 Updated: labs go quiet as researchers brace for long-term coronavirus disruptions . Sci. AAAS . See https://www.sciencemag.org/news/2020/03/updated-labs-go-quiet-researchers-brace-long-term-coronavirus-disruptions (accessed on 15 July 2020). Google Scholar

. 2020 Starving monkey ‘gangs’ battle in Thailand as coronavirus keeps tourists away. livescience.com. See https://www.livescience.com/macaque-fight-thailand-temple-coronavirus.html (accessed on 1 October 2020). Google Scholar

. 2020 Photos: wild goats roam through an empty Welsh Town. The Atlantic. See https://www.theatlantic.com/photo/2020/03/photos-llandudno-goats/609160/ (accessed on 20 July 2020). Google Scholar

Derryberry EP, Phillips JN, Derryberry GE, Blum MJ, Luther D

. 2020 Singing in a silent spring: birds respond to a half-century soundscape reversion during the COVID-19 shutdown . Science 370, 575-579. (doi:10.1126/science.abd5777) Crossref, PubMed, ISI, Google Scholar

Suraci JP, Clinchy M, Zanette LY, Wilmers CC

. 2019 Fear of humans as apex predators has landscape-scale impacts from mountain lions to mice . Ecol. Lett. 22, 1578-1586. (doi:10.1111/ele.13344) Crossref, PubMed, ISI, Google Scholar

Gaynor KM, Brown JS, Middleton AD, Power ME, Brashares JS

. 2019 Landscapes of fear: spatial patterns of risk perception and response . Trends Ecol. Evol. 34, 355-368. (doi:10.1016/j.tree.2019.01.004) Crossref, PubMed, ISI, Google Scholar

. 2020 Pandemic lockdown stirs up ecological research . Science 369, 893. (doi:10.1126/science.369.6506.893) Crossref, PubMed, ISI, Google Scholar


Interaction between Different Species | Ecology

In the great web of life, which exists in nature, living organisms not only live in an environment, but are also themselves a part of the dynamic environment for other organisms.

The relationship between one species and another within a community has evolved through their interactions, based on the requirement and the mode of nutrition and shelter and also on the habits of species. The relationships between members of different populations are termed interspecific relations.

The interactions between populations of species in a community are broadly divided into two categories:

(i) Positive (beneficial) and

(ii) Negative (inhibition) interactions.

This depends upon the nature of effect on the interacting organisms of different species.

Positive Interactions:

Symbiosis or Mutualism:

When two species live together in a close association that is helpful to both species, the relationship is known as symbiosis. The oxpecker bird and the rhinoceros exhibit this relationship. The oxpecker receives protection and obtains food from the ticks and other pests infesting the rhino’s skin.

The rhino receives cleaning and warning of approaching dangers. Algae and fungi live together in symbiotic relationship in lichens, whereas the fungi live on the roots of higher plants, and the association is known as mycorrhiza. In lichens, the algae are able to produce food by photosynthesis, and the fungi obtain water and minerals and provide attachment for the lichen.

The bacterium Rhizobium leguminosarum found in the root nodules of leguminous plants fixes atmospheric nitrogen in the soil in the form of nitrates which is used by the plant, and in return plant supplies water, minerals and organic food to the bacterium. The cyanobaterium Anabaena also lives in symbiotic association with water fern Azolla. Bacteria in the gut of some domestic animals help in cellulose digestion.

Sea anemone is a typical example of facultative mutualism, wherein animal gets attached to the shell of hermit crab. The sea anemone growing on the back of the crab provides camouflage and protection, and in turn, the sea anemone is transported to reach new sources of food. This type of mutualism in called protoco-operation.

Green Hydra presents another example of mutualism, this animal has green photosynthetic alga in the protective ectoderm. The alga gives off oxygen benefitting the animals which, in turn supplies CO2 and nitrogen to the plant.

Some organisms live together so that one organism benefits by the relationship while the other organism is neither helped nor harmed. This type of relationship is known as commensalism. An example of this association is the relationship between the shark and the small remora fish.

The remoras may attach themselves to the shark as it swims through the water. When the shark finds food, the remoras eat some of the food not consumed by the shark. The shark is not harmed by the remora, while the remora is helped. The attachment of the sedentary sea anemone to the body of a hermit crab and barnacles to a whale are other examples of commensalism.

Some epiphytes, such as orchids, mosses, ferns, etc., are the best examples. Epiphytes depend upon the other trees for support and nutrients. They manufacture their own food but do not help the supporting plant any way.

Several woody climbers (lianas) take the support of the trees for exposing their canopy above ground without doing any harm to the supporting trees.

Negative Interactions:

Certain interactions between different species give rise to negative effect on either or both species. Parasitism and predation are interaction where one species gains and the other suffers. While in the interaction called competition both species are harmed.

This is a relationship in which one organism, the parasite spends much or all of its life living in or another organism, the host. The parasite is dependent upon the host for food.

The parasite benefits from the relationship and the host is always harmed. Parasites may bring about the death of their host, but most often only weaken their host. Human parasites may be external (ectoparasites) such as body lice, ticks, mites and leeches, or internal (endoparasites) such as tapeworms, some types of roundworms, malarial parasite, microfilaria and guineaworm.

The dodder (Cuscuta), broomrape (Orobanche), mistletoe (Viscum), Dendrophthoe, Striga and Rafflesia are parasitic plants. Certain bacteria are parasitic on human beings and animals and cause fatal diseases such as Vibrio coma (cholera), Mycobacterium tuberculosis (tuberculosis).

Salmonella typhosa (typhoid fever), Mycobacterium leprae (leprosy), etc. A large number of fungi are parasitic on several crop plants causing diseases like rusts, smuts, blights, mildews and wilts.

A parasite usually parasitizes a host which is larger in body size than it, and ordinarily it does not kill the host, at least not until it has completed its reproductive cycle.

This is commonly associated with the idea of strong attacking the weak such as the tiger pouncing upon the deer, the hawk upon the sparrow, and the frog upon the insects and so on. A species such as the frog may be both a prey and a predator. The relationship between a snake and a rat is more than that between a prey and a predator as the snake also seeks shelter in the rat holes.

Thus “predation represents a direct and often complex interaction of two or more species, of the eaters and being eaten.” This is a negative interaction which results in negative effects on the growth and survival of one of the two populations.

In this type of association and interaction one species (predator) kills and feeds on second species (prey). Predation is important process in the community dynamism. Predator is always stronger than pery. From population ecology point of view predation is the action and reaction in the transfer of energy from one trophic level to the other.

It represents a direct and complex interaction between two or more species of eaters and eaten.

Parasites and predators have some points of difference, they are as follows:

Parasites, like the predators, limit the population of the host species, but they are generally host-specific, and do not have choice or alternatives like predators.

Parasites are smaller in size and have higher biotic or reproductive potential composed to the predators.

Parasites have poor means of dispersal and require specialised structures to reach or invade the host. While the predators are quite mobile and swift, and capable of capturing the prey.

However, newly acquired predators and parasites are more damaging than the older ones, as the latter are familiar and the species getting affected have adjusted by then.

The amount of food, light, space, minerals and water that are available in a particular habitat is limited. As a result, organisms are in competition with one another for one or more of these factors. Competition occurs not only among individuals of a given species but also between members of two or more species.

For instance, carnivorous animals such as tigers and leopards, compete for the prey. The members of kingdom Plantae, such as trees, shrubs and herbs in a forest are to compete for sunlight, nutrients and water and biological agents for pollination and dispersal.

Populations may compete directly, leading to the extinction or adaptation of one of them. Many animals establish territories within which they live and which they will defend against other of their species who try to intrude. By staying in their own territories, competition and combat are lessened.

(i) Interspecific competition occurs between the individuals of the same species and their requirements are common and,

(ii) Interspecific competition occurs between individuals of two different species occurring in a habitat.

Generally the intraspecific competition is more intense than interspecific competition. Requirements of individuals of same species are similar, and therefore, competition is more intense.

This is a type of direct food relationship where animals such as a vulture or hyena, or a jackal feed on other animals which have died naturally or have been killed by another animal. For instance, the omnivorous animals such as the common crow consume many types of foods including dead animals.

Many insects, reptiles, birds and mammals get shelter and protection on trees and shrubs. Many animals protect them by a highly interesting device, called mimicry. This phenomenon is seen in many insects where they develop a superficial resemblance in shape and colour to specific plant parts on which they live.

The examples are—the stick insect (Carausius morosus) mimics thin dry branches the dead leaf butterfly (Kalima parolecta) resembles a dry leaf, whereas the praying mantis (Mantis religiosa) and Rhyllium frondosum resemble with the green leaves. By their mimicry, they conceal themselves from predators and other foes.

For the survival of a community, the availability of the other nonliving components is also important, and sometimes one of the components plays a dominant role in determining the character of the community. For example, a community having fruit bearing trees may consist mainly of fruit eating animals, such as bats and insects.

On the other hand, in a grassland there will be only seed eating birds, mice, voles and predatory birds living on others lower down the food chain. In a marshy land, frogs, toads, fish, aquatic insects and water birds which feed on aquatic insects are maximum.

Aquatic plants adapted to different intensities of light may be found either at the surface or at different depths in water. Thus the environmental factors act as the determinants of the types of individuals in a community.


Methods

Field experiment description

The long-term fertilization experiment commenced at the Yingtan National Agroecosystem Field Experiment Station of the Chinese Academy of Sciences (28°15′20′′ N, 116°55′30′′ E) in Jiangxi Province, China. The experiment site has a typical subtropical climate with a mean annual temperature of 17.6 °C and precipitation of 1795 mm. The soil is classified as Ferric Acrisol according to the Food and Agricultural Organization (FAO) classification system. The long-term field experiment followed a completely randomized design with three replicates. The experiment was conducted since 2002, which consisted of 12 concrete plots with the following size: 2 m long, 2 m wide, and 1.5 m deep. The four manure treatments were (1) no manure (M0) (2) low manure with 150 kg N ha −1 years −1 (M1) (3) high manure with 600 kg N ha −1 years −1 (M2) and (4) high manure with 600 kg N ha −1 years −1 and lime applied at 3000 kg Ca (OH)2 ha −1 3 years −1 (M3). Pig manure had an average total carbon content of 386.5 g kg −1 and a total nitrogen content of 32.2 g kg −1 on a dry matter basis. The field was planted annually with corn monoculture (cultivar Suyu No. 24) from April to July. Each plot was grown with 20 maize plants. No management measures were taken with the exception of weeding by hand.

Soil sampling, physicochemical properties and phosphomonoesterase activity assays

Soil samples from each plot were collected after the harvest in late July 2018. In each plot, 10 soil cores were collected from the surface layer (0−20 cm) using a Dutch auger (5 cm diameter), and were mixed to form a composite sample. After field collection, fresh samples were placed on ice and immediately transported to the laboratory, where they were sieved (2 mm) to remove visible residues and then homogenized. Soil samples were subdivided into three subsamples for analyzing soil physicochemical properties, the AMF community, the assemblages of fungivorous protists, and nematodes.

Soil pH was measured by a glass electrode with water:soil ratio of 2.5:1 (v/w). SOM was determined by wet digestion using the potassium dichromate method [38]. TN was determined using the micro-Kjeldahl method [39]. Inorganic N species (NH4−N and NO3−N) were extracted with 2 M KCl and detected on a continuous low analyzer (Skalar, Breda, Netherlands). TP was digested with HF−HClO4 and AP was extracted with sodium bicarbonate, respectively, which were determined using the molybdenum-blue method [40, 41]. TK was digested with HF−HClO4 and AK was extracted with ammonium acetate, respectively, which were detected by atomic absorption spectrophotometer [42]. Gravimetric SWC was measured by drying the soil for 48 h at 105 °C. The acid and alkaline phosphomonoesterase activities were assayed using p-nitrophenyl phosphate (p-NP) as the substrate with the buffer adjusted to pH 6.5 and 11.0, respectively [43]. After incubation, the absorption was measured at 405 nm, and acid and alkaline phosphomonoesterase activity were expressed as mg p-NP g −1 soil h −1 .

Lipid extraction and analysis

The biomasses of AMF and saprotrophic fungi were characterized by neutral lipid fatty acid (NLFA) and phospholipid fatty acid (PLFA) analysis, respectively [44]. Briefly, total lipids were extracted from 2 g freeze-dried soil samples with a mixture of chloroform, methanol, and citrate buffer (1:2:0.8, v/v/v), and then fractionated into neutral, glyco-, and phospho-lipids by silica acid columns. The neutral lipids and phospholipids were converted to methyl esters by alkaline methanolysis, and then quantified by a HP 6890 Series gas chromatograph (Hewlett–Packard, Wilmington, DE, USA). Identification was performed using fungal fatty acid standards and MIDI peak identification software (Microbial ID Inc., Newark, DE, USA). The methyl nonadecanoate (19:0) was used as internal quantitative standard. Fungal biomass was calculated by summing the abundance of specific biomarkers and expressed as nmol NLFA/PLFA g –1 dry soil. The biomarker NLFA 16:1ω5c was used as the indicator of AMF biomass, and the biomarkers PLFA 18:1ω9c and 18:2ω6,9c as saprotrophic fungal biomass [45, 46].

Illumina sequencing and bioinformatic analysis

The soil DNA was extracted from 0.5 g samples using the DNeasy PowerSoil Kit (Qiagen, Hilden, Germany) following the manufacturer’s instructions. The extracted DNA was dissolved in tris-EDTA buffer and quantified by the ND-1000 spectrophotometer (NanoDrop Technologies, Wilmington, DE, USA). For the AMF and protistan communities, triplicate PCR amplifications of the 18S rRNA gene fragments were performed using the primer sets of AMV4.5NF/AMDGR [47] and TAReuk454FWD1/TAReukREV3 [48], respectively. The 8-bp barcode oligonucleotides were added to distinguish the amplicons from different soil samples. Reaction mixtures (20 μL) contained 2 μL of 10 × reaction buffer, 0.25 μL of each primer (10 μM), 2 μL of 2.5 mM dNTPs, 10 ng template DNA, and 0.4 μL FastPfu Polymerase. The PCR protocol was as follows: an initial pre-denaturation at 95 °C for 5 min, followed by 28 cycles of denaturation at 94 °C for 30 s, annealing at 60 °C for 30 s, and extension at 72 °C for 45 s and a final extension at 72 °C for 10 min with a ramp of 3 °C s −1 . All amplicons were cleaned and pooled in equimolar concentrations in a single tube, after which they were subjected to library preparation, cluster generation, and 300 bp paired-end sequencing on an Illumina MiSeq platform (Illumina, San Diego, CA, USA).

Raw sequences were quality screened and trimmed using the Quantitative Insights into Microbial Ecology (QIIME package version 1.9.1) pipeline [49]. Sequences that fully matched the barcodes were selected, and sequence processing was performed including quality trimming, demultiplexing, and taxonomic assignments. QIIME quality trimming was performed in accordance with the following criteria: (1) no ambiguous bases, and (2) the minimum sequence length of 283 bp (AMF) and 516 bp (protist) after trimming. The assembled reads were processed using de novo chimera detection in UCHIME [50]. Thereafter, the sequence reads from each sample were clustered to provide similarity-based operational taxonomic units (OTUs) that had 97% identity cutoffs [51]. Finally, the sequences were subjected to a similarity search using the MaarjAM AMF database and the Protist Ribosomal Reference database (PR2, v4.3), respectively [16, 52]. Prior to downstream analyses, AMF and protistan OTUs were extracted from the individual OTU table to represent the structure of soil AMF and protistan communities. For the 3% cutoff, 537 AMF and 2798 protistan OTUs were observed out of 313,584 and 480,107 high-quality sequences, respectively. Alpha diversity and Bray-Curtis distances for a principal coordinate analysis of AMF, fungivorous protist, and nematode communities were calculated after rarefying all samples to the same sequencing depth. Functional units of protists were categorized according to their feeding habits [26, 53].

AMF colonization and root morphology

Plants from plots were randomly selected for the determination of AM root colonization (in percent) [54]. Briefly, roots of each plant were carefully washed with distilled water for three times in order to remove soil particles, and then cut into 1-cm-long fragments. Subsequently, root fragments were randomly selected and cleared in 10% KOH solution in a boiling water bath for 45 min. After rinsing with distilled water, root fragments were immersed in 1% HCl for 15 min, bleached in 10% hydrogen peroxide for 10 min. Then, roots were cleaned and stained for two hours in 0.02% (w/v) aniline blue solution at room temperature. Fifty root fragments per replicate were examined at × 100−400 magnification under a compound microscope for the presence of AM structures. AMF colonization was calculated as the percentage of the total root segments containing visible AMF structures.

Shoot biomass, root biomass, and grain yield of maize were measured immediately after harvest. We processed digital images of root system morphology using a desktop scanner and determined root length, surface area, average diameter, root volume, and number of tips, forks, and crossings using WinRhizo software (Regent Instruments, Québec, Canada). All measurements were expressed per g of root mass and scaled to a per m 2 basis based on total standing root biomass (g m −2 ) at the plot level.

Identification and isolation of nematode assemblages

Nematodes were extracted from 100 g fresh soil using the shallow dish method [55]. Four functional groups of nematode assemblages, including bacterivores, fungivores, plant parasites, and omnivores and predators, were identified based on known feeding habits, stoma, and esophageal morphology [9]. Nematode density was counted and expressed as nematode numbers per 100 g of dry weight soil.

Two kinds of fungivorous nematodes (Aphelenchoides and Aphelenchus) were separately picked out into 10 mM sterile phosphate buffer saline (pH 7.0) under a dissecting microscope according to morphological characteristics. These harvested nematodes were then introduced into 2% sodium hypochlorite solution for 30 s to avoid microbial interference from the body surface, then washed five times with sterile distilled water. AMF spores in the final wash water were isolated and enumerated by wet-sieving and sucrose gradient centrifugation [56, 57], and AMF abundance indicated by copy numbers of the 18S rRNA gene were quantified. Neither AMF spore nor AMF abundance was detected, suggesting that nematodes had been surface sterilized. In order to verify the predation of fungivorous nematodes on AMF, 30 individuals of Aphelenchoides or Aphelenchus were chosen and transferred into a 1.5 mL centrifuge tube under sterile conditions for DNA extraction.

Quantitative polymerase chain reaction (qPCR) and reverse transcription-PCR (qRT-PCR)

Total DNA of surface-sterilized Aphelenchoides or Aphelenchus was extracted using a DNeasy Blood & Tissue Kit (Qiagen, Hilden, Germany) according to the manufacturer’s instructions. AMF abundance inside fungivorous nematodes was assessed by copy numbers of AMF-specific 18S rRNA gene using the same primers as described above. The qPCR assays were conducted in triplicate by using the fluorescent dye SYBR-Green approach on an ABI 7500 Sequence detection system (Applied Biosystems, Foster City, CA, USA). The standard curve for AMF was obtained using 10-fold serial dilutions (10 2 −10 8 copies) of plasmid DNA carrying the corresponding gene fragment. Target DNA was successfully amplified from all samples with an efficiency of 95−107% and correlation coefficients higher than 0.99, except for negative controls. AMF abundance inside Aphelenchoides or Aphelenchus was calculated as the copy number of AMF 18S rRNA gene per nematode, respectively.

Root total RNA was isolated using RNA Plus (Takara, Dalian, China) with the guanidine thiocyanate extraction method. Then, 1.2% agarose gel and the NanoDrop ND-1000 spectrophotometer were used to determine quality and quantity RNA (NanoDrop Technologies, Wilmington, DE, USA), respectively. DNase was used to eliminate the potential trace of genomic DNA in RNA samples. Root RNA was reversely transcribed into cDNA as templates for RT-PCR using the Roche reverse transcription kit. The qRT-PCR was carried out on an ABI 7500 Sequence detection system (Applied Biosystems, Foster City, CA, USA). To support the notion that mycorrhizal colonization regulates mycorrhizal P acquisition in roots, the ZmPht13 and ZmPht16 genes encoding P transporter of the PHT1 family were monitored. The ZmPHT13 and ZmPHT16 genes were amplified with the primer pairs [58]. The expression level of the maize Actin 1 gene was used as an internal control. The relative transcript level was normalized as percent of the corresponding actin transcript levels.

Statistical analysis

One-way analysis of variance (ANOVA) was performed to assess the effects of manure treatments on soil properties, the AMF communities, the assemblages of fungivorous protists and nematodes, plant performance using Tukey’s HSD test in SPSS 23.0 software (SPSS, Chicago, IL, USA). All statistical analyses were conducted based on 12 samples (4 fertilization treatments × 3 replicates). Principal coordinate analysis (PCoA) was used to evaluate the Bray-Curtis distances of the AMF, protistan, and nematode community compositions under manure treatments [59]. We conducted the ‘capscale’ function of the R package vegan (version 3.1.2) to calculate the Bray-Curtis dissimilarities for PCoA and ‘permutest’ permutation-based testing for the calculation of the significance values [60].

To describe the complex co-occurrence patterns in mycorrhizal–fungivores networks, we constructed a correlation matrix by calculating multiple correlations and similarities with Co-occurrence Network (CoNet) inference [61]. The OTUs detected in more than three-fourths of the soil samples at the same depth were kept for the network construction. We transformed the distribution matrix of AMF, and fungivorous protists and nematodes into the relative abundance values. Then, we used an ensemble approach that combined four measurements, including Pearson and Spearman correlations and Bray-Curtis and Kullback-Leibler dissimilarities. A valid co-occurrence was considered a statistically robust correlation between species when the correlation coefficient (r) was > 0.8 or < − 0.8 and the P value was < 0.01. Those P values < 0.01 were adjusted by a testing correction using the Benjamini-Hochberg procedure to reduce the chances of obtaining false-positive results [62]. Co-occurrence networks were visualized via Gephi software [63]. Modules were defined as clusters of closely interconnected nodes (i.e., groups of co-occurring microbes) [64]. The microbial networks were searched to identify highly associated nodes (clique-like structures) using Molecular Complex Detection (MCODE) introduced for the Cytoscape platform [65]. We calculated the first principal component of the modules (module eigengene) in the standardized module expression data for the co-occurrence networks [66]. The correlations between soil properties, network module eigengenes, AMF colonization, the expression of ZMPht16 gene, and plant performance were evaluated using Spearman’s rank correlation test.

Random forest tool was performed to quantitatively estimate the important predictors of AMF colonization and the expression of P transporter genes containing soil properties, AMF community, and the assemblages of fungivores. Random forest modeling was conducted using the randomForest package [67] and the model significance and predictor importance were determined using the A3R and rfPermute packages, respectively [68, 69]. Based on random forest analyses, the significant predictors were further chosen to perform a structural equation modelling (SEM) analysis. SEM analysis was applied to determine the direct and indirect contributions of soil properties and mycorrhizal-fungivore interactions to AMF colonization and plant productivity. SEM analysis was conducted via the robust maximum likelihood evaluation method using AMOS 20.0. A path indicated the partial correlation coefficient and interpreted the magnitude of the relationships between two parameters. Latent variables were used to integrate the effects of multiple conceptually related observed variables into a single-composite effect, aiding interpretation of model results. The SEM fitness was examined on the basis of a non-significant chi-square test (P > 0.05), the goodness-of-fit index, and the root mean square error of approximation [70].


Watch the video: Community interactions - competition, predation, symbiosis (June 2022).


Comments:

  1. Adiv

    There is something in this. I used to think differently, thanks for the explanation.

  2. Mazuzshura

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  3. Daijar

    New posts, IMHO, are too rare these days :)

  4. Damaskenos

    Yes good

  5. Bryceton

    This seems to do the trick.



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