BIO 212 EXAM 4 (FINAL)

Deer are hosts of ticks but are not reservoirs of B. burgdorferi- their immune systems detect and kill the bacterium. But a tick with a prior bacterial infection can consume a blood meal from a deer and then bite and infect a human. The fitness effects of a deer on B. burgdorferi can be summarized as:

- or + depending on whether the deer is the tick's last host.

If the GPP of a grassland is 5000 kcal/m^2/year and 55% is used up by cellular respiration, what's the NPP?

225 kcal/m^2/year

The range of Burmese pythons in Florida is expanding rapidly. List at least one abiotic factor and one biotic factor that might limit the range of pythons.

Abiotic factors: cold temperatures of the north, the occurrence of deep sea-water surrounding southern Florida. Biotic factors: competition for food, the occurrence of parasites, or the spread of disease; increased predation on eggs or juveniles.

What is a biodiversity "hot spot"?

An area with high species richness and high threat to those species

Using the graph, estimate the # of minutes of foraging per hour before and after the sound exposure. Then predict the effect of sonar on the fitness of blue whales.

Before the sound exposure, the whale foraging for about 30min per hour. After the sound exposure the whale either stopped foraging completely or reduced the foraging rate to less than about 5min per hour. If the sound was repeated or ongoing, it could affect the whales fitness because the whale would stop feeding, and thus stop obtaining energy, and so it would have fewer resources to produce offspring, The sonar might also disrupt whale mating behavior, further reducing fitness.

Whats the main type of vegetation in a tropical wet forest?

Broad-leaved evergreen trees

Biologists claim that the all-taxa survey now underway at the Great Smoky Mountains National Park in the US will improve their ability to estimate the total number of species living today. Discuss the benefits and limitations that this data set will provide in understanding the extent of global biodiversity.

By comparing the number of species estimated to reside in the park before and after the survey, biologists will have an idea of how much actual species diversity is being underestimated in other parts of the world, where research was at the level of Great Smoky Mountains National Park before the survey. The limitation is that it may be difficult to extrapolate from the data-- no one knows if the situation at this park is typical of other habitats.

There are debates about what action the military should take to avoid harming the whales. How could you apply cost-benefit analysis to this problem?

By studying the pattern of sonar use by the military, the behavioral patterns of whales, and the effect of sonar on whales, it could be possible to reduce the costs to whales with or without reducing the benefits to the military. For example, the military might be able to limit sonar use to locations that are far away from known whale migrations routes and/or to times of the year when whales are not nearby.

Hamilton's rule states that an altruistic allele could spread i a population if Br > C, where B represents the fitness benefit to the recipient, r is the coefficient of relatedness between altruist and recipient, and C represents the fitness cost to the altruist. If r = 0.5 between the altruist and the recipient, what would the ratio of costs to benefits have to be for the altruistic allele to spread?

C/B < 0.5

What is a disturbance? Consider the role of fire in a forest. Compare the consequences of high-frequency versus low-frequency fire and the high severity versus low severity of fire.

Disturbance is any short-lived event that changes the distribution of resources. Compared to low-frequency fires, high frequency fires would tend to be less severe (less fuel builds up) and would tend to exert more intense natural selection for adaptations to resist the effects of fire. Compared to low-severity fires, high-severity fires would open up more space for pioneering species and would tend to exert more intense natural selection for adaptations to resist the effects of fire.

What does species richness refer to? True or False - The functional diversity of species in an area

False

What does species richness refer to? True or False -The evenness of species in an area

False

What does species richness refer to? True or False -The phylogenetic diversity of species in an area

False

Pioneer species tend to have high __________ and lower survivorship.

Fecundity

Based on what you have learned in this chapter about global trends in terrestrial ecosystems, what is currently the largest threat to the wet tropical forests in Central America?

Habitat destruction, such as clearing of forests for coffee plantations.

Evaluate this statement: Leaving some natural forest in and around coffee plantations is a "win-win" situation-- a win for ecosystems and a win for farmers.

It does look like a win-win situation. Leaving more natural forest increases the biodiversity at the genetic, species, and ecosystem levels, increasing the chance of resilience and ecosystem function. Leaving some of the natural forest is a win for farmers because the forest provides ecosystem services, such as pest management, that farmers rely on for a successful business.

Look again at the graph in Q12, why did the researchers bother to collect data from the coffee shrubs before adding the nets to treatment plots to exclude birds?

It was very important for the researchers to demonstrate that there was no difference between control and treatment plots at the start of the experiment, so they could be sure that any changes seen was due to the exclusion of birds and not some other factor such as a difference in shade, water availability, abundance of beetles and so on

Volunteer conservation organizations have hosted "lionfish derbies" and lionfish cookouts to promote the capture of thousands of lionfish from reefs in Florida and the Bahamas. Conservationists are also trying to promote a fishery for these small but tasty fish. Give one reason that it would be easy to promote the consumption of lionfish. Describe one possible challenge to this effort.

It would be easy to convince people about the devastating effects of invasive species like lionfish on coral reef health; most people love coral reefs and would be highly motivated to eat lionfish if it helped protect coral reefs. On the other hand, lionfish are small , pretty, and have venomous spines that may not sound appetizing and could discourage handling. Also, its not intuitive for humans to kill one pretty thing to protect another.

A life table would help researchers make predictions about python population growth. If you were to track a cohort of pythons over time to construct a detailed life table, what kind of data would you want to collect?

It would be ideal to measure both the surivivorship and the age specific fecundity.

Which statement is the best explanation for seasonality on Mars?

Mars is tilted on its axis

Some biologists prefer to focus efforts on preserving endangered species while others prefer to focus on preserving ecosystems. Whats your advice to biologists based on the evidence from this chapter?

No single approach is correct, there's good arguments for both efforts. In a case like the orangutans of Borneo, its not possible to save the orangutans without saving their ecosystem. On the other hand, its easier to attract money and volunteers to help save a charismatic primate like an orangutan than it is to save a patch of forest. Both types of efforts are needed; their relative importance depends on the circumstance.

Whales communicate with one another using sound. What is one benefit and one cost of this?

One benefit using sound underwater is that it travels much further than light, enabling communication over long distances where visibility is poor. One disadvantage is that sound is short lived and must be repeated to be effective, which requires time & energy.

The five main levels of study in ecology from smallest to largest

Organismal Population Community Ecosystem Biosphere/Global

Why is there a trade-off between survivorship and fecundity

Resources such as time and energy are limited, so survivorship and fecundity cannot both be maximized simultaneously

Which of the following species is most likely to have a Type III survivorship curve?

Thale cress plants, Arabidopsis thaliana

Where do rain shadows exist?

The region beyond a mountain range that receives dry air

Predict why the wale foraged at a depth of 100-170 m.

The whales food was most plentiful at this depth.

The abundance of birds and other predators of borer beetles depends on how much natural forest is left within and around the coffee plantations. Whats the approx percentage increase in borer predators per hectare if forest cover is doubles from 15-30%?

There are about 4 borer predators per hectare at 15% cover and about 11 borer predators per hectare 30% cover, a difference of 11/4 x 100= 2.75 or 275%. That is, the abundance of borer predators is about 3x higher

The maps shown here chronicle the loss of old-growth forest (more than 200 years old) that occurred in the US. In your opinion, under what conditions is it ethical for conservationists who live in the US to lobby government officials in Brazil, Indonesia, and other tropical countries to slow the rate of loss old-growth forest?

There's no correct answer. One argument is that conservationists could approach officials in tropical countries including Brazil and Indonesia, and offer to help them learn from the mistakes made in developed nations. Its better to preserve enough forests to maintain biodiversity and keep ecosystem services intact, thus avoiding the expenditures that developed countries face in cleaning up pollution and restoring ecosystems and endangered species.

Fitness is measured by: Number of Viable Offspring

True

True or false in regards to exponential growth: The per capita growth rate is constant.

True

True or false in regards to exponential growth: The population is growing

True

What is one expected consequence of global climate change?

Variability in rainfall will increase

Pesticides are generally ineffective in killing coffee berry borers. Ecologist Daniel Karp and colleagues conducted a study in Costa Rica to determine if natural predatirs like birds reduce the beetle population. The researchers selected 12 control plots and used nets to exclude birds from 12 similar treatment plots. What is the take home message from the graph?

When birds are excluded, the percentage of berries with borers approximately doubled. The difference is considered statistically significant because the P value is less than 0.05

Suppose that a record snows blanket your campus this winter. Your friend says this is proof that global warming isn't really occurring. Whats the flaw in your friend's logic?

While the average global temperature is increasing, local temperatures and precipitation will vary.

Explain why the construction of wildlife corridors can help maintain genetic diversity in a fragmented landscape.

Wildlife corridors facilitate the movement of individuals. Corridors allow areas to be recolonized if a species is lost and enable the introduction of new alleles that an counteract genetic drift and inbreeding in small, isolated populations, which tend to reduce genetic diversity.

The population size of mountain pine beetles in the American Northwest has long been held in check by freezing tempertures during the winters. As winters warm, populations of pine beetles are increasing, killing whitebark pine forest. Grizzly bears rely on the nuts of whitebark pine trees. Do you think climate change is affecting the fitness of the grizzly bear population?

Yes because climate change is decreasing the food supply of the bears, which is likely to reduce their ability to survive or reproduce.

In relation to humans, B. burgdorferi is a/an ________ and the tick is a/an _________.

endoparasite/ectoparasite

What do ultimate explanations of behavior focus on?

Adaptive significance of behavior; how behavior affects fitness, how behavior has evolved

Fitness is measured by: Strength

False

What community property does the red arrow in the model represent?

High resilience

Explain how the open ocean is similar to the desert, and how it isn't.

Like deserts, open oceans have plenty of sunlight but very low productivity. Unlike deserts, which are water limited, open oceans are nutrient limited.

The male cuttlefish in the chapter-opening photo can rapidly change their skin colors to flash warning patterns to rivals. Predict the proximate and ultimate causes of this behavior

Proximate: when a male cuttlefish sees another male especially if its near a potential mate its brain sends a signal to its skin to change to a warning display. Ultimate: males that have higher fitness if they happen to have adaptations that enable them to intimidate rival males and thus produce more offspring with females.

Evolutionary biologist Hopi Hoekstra and colleagues have hypothesized that the burrow-digging behavior of mice is heritable--innate and not learned. Design an experiment to test this

A good experiment would assess the shape of underground burrows in an environment that excludes the possibility of learning. For example, you could measure burrow shapes of mice that were raised in the absence of other mice and of mice raised around other mice

Why does altruism seem paradoxical?

Alleles that cause an organism to behave altruistically should be selected against since these alleles should lower the organism's fitness.

Make a rough sketch of the age distribution in a developing versus a developed country, and explain why the shapes of the diagrams are different. How is AIDS, which is a sexually transmitted disease, likely affecting the age distribution in countries hard hit by the epidemic?

As a sexually transmitted disease, AIDS will reduce the number of sexually active adults. If the epidemic continues unabated, the numbers of both reproductive-age adults and children will decline, causing a top-heavy age distribution dominated by older adults and the elderly.

White-footed mice occupy a broad ecological niche- they occur in most communities regardless of habitat quality. Many other species, like the opossum, are absent from low quality forest fragments. Based on this info propose a hypothesis to explain the observed relationship between increased forest fragmentation and increased incidence of Lyme Disease.

As forest fragmentation increases, species richness will decline. As species richness declines, white footed mice will still be present in the population, but species like opossums will be absent. Since mice are huge reservoirs to Lyme bacterium and species like opossums are not, a greater percentage of animals present in forest fragments will host the Lyme bacterium.

During the carboniferous period, plant growth was extensive but rates of decomposition slowed. As a result, large amounts of biomass accumulated in terrestrial environments. The fossil record indicates that atmospheric oxygen increased, atmospheric carbon dioxide decreased, and global temperatures dropped. Explain:

Atmospheric oxygen would increase due to extensive photosynthesis, but carbon dioxide levels would decrease because the rate of photosynthesis was high but the rate of decomposition was low. The temperature would drop because fewer greenhouse gasses would be trapping heat reflected from Earths surface.

Researchers hypothesize that the severe winter of 2010 caused the decline in the number of pythons encountered that year. Is cold weather typically a density-dependent factor or a density-independent factor?

Cold weather is typically a density- independent factor because it affects the pythons the same way no matter how many pythons there are. A density- dependent factor, such as competition for food, increases with increasing python density.

Is it true that all organisms forage optimally?

Evolution favors organisms that forage optimally, thus maximizing benefits and minimizing costs. But individuals are not making conscious choices, individuals vary in populations, and environmental circumstances vary. As a result, some individuals will forage sub optimally and suffer reduced fitness due to evolutionary trade-offs, environmental constraints, and genetic and historic constraints.

Cite an example to explain why species interactions are conditional and dynamic.

Ex) A pollination relationship between pollinator and flower is mutualistic if the pollinator receives a nectar reward and the flower receives pollination services.

Burmese pythons were first found in the wetlands of Everglades National Park in the 1980's but only rarely. The accompanying graph shows what happened next. Most of the data are derived from chance encounters of pythons on roads. How would you describe the type of population growth in pythons from 2000 to 2008

Exponential

Fitness is measured by: Body Size

False

Fitness is measured by: Speed

False

Once nutrients sink to the bottom of lakes, they're no longer available to organisms.

False

T/F about inducible defenses? They are always present; thus, an individual is always able to defend itself.

False

T/F about inducible defenses? They make it possible for a consumer to launch suprise attacks

False

The ocean is so vast that its not influenced by human impacts

False

True or false in regards to exponential growth: The per capita growth rate increases rapidly over time.

False

True or false in regards to exponential growth: The per capita growth rate is very high

False

True or False: Most of the net primary productivity that's consumed is used for growth by primary consumers.

False, most NPP is used for cellular respiration in primary consumers

True or False: About effects of clear cutting on the Amazon rain forest, then explain your reasoning. -Nutrient export is likely to decline

False, nutrient export is likely to increase because most of the nutrients were stored in the biomass that was removed and further erosion of soil will occur.

True or False: About effects of clear cutting on the Amazon rain forest, then explain your reasoning. -Atmospheric CO2 is likely to decline

False, trees absorb CO2 from the atmosphere so the removal of trees will remove this carbon sink.

When wild plant and animal populations are logged, fished, or hunted, only the oldest or largest individuals tend to be taken. Many of the commercially important species are long lived and are slow to being reproducing. If harvesting is not regulated carefully and exploitation is intense, what impact does harvesting have on a populations age structure? How might harvesting affect the population's life table and growth rate?

Fewer older individuals will be left in the population; there will be relatively more young individuals. If too many older individuals are taken, population growth rate may decline sharply as reproduction stops or slows.

Researchers have measured the effects of periodic forest fires on primary productivity in Amazon rain forest plots, comparing years with average precipitation and years with severe drought. Propose which controls would be necessary for such studies.

For measuring the effects of forest fires on primary productivity in forest plots, a good control would be forest plots that were comparable to the treatment plots in every way possible except they didn't burn or were prevented from burning.

Researchers have measured a positive correlation between forest fragmentation and incidence of Lyme disease. According to the theory of island biography, how do you predict fragmentation will affect species richness?

Forest fragmentation will subdivide large areas of habitat into many small islands of habitat, causing species richness to decline.

Which of the following is the longest-lived reservoir for carbon?

Fossil Fuels

Why is the common phrase "humans and animals" not accurate in biology? Suggest one way that a more scientific outlook could boost conservation efforts.

In biology, humans are a type of animal, so saying "humans and animals" is incorrect, like saying "apples and fruit". Switching from "humans and animals" to a "human and other animals" worldview could encourage conservation in a number of ways. If people feel more closely related to other animals, we may be more motivated to prevent extinctions.

J.B.S. Haldane once remarked that he'd be willing to lay down his life to save two brothers or eight cousins. Explain what he meant.

Individuals have a r of 1/2 with full siblings and an r of 1/8 with first cousins. If the biologist will lose his life, he needs to save two siblings or eight first cousins, to keep the "lost copy" of his altruism alleles in the population.

Devegetation has what effect on ecosystem dynamics?

It increases nutrient export.

Indicate what is correct and incorret about this statement: If lizards want to survive during climate change, they can evolve new life-history traits.

Its true that the life-history traits of lizards may evolve in response the climate change, but its incorrect to say that they will evolve because lizards want or need them to. Natural selection merely sorts existing variation; lizards with heritable traits that increase their fitness will increase in frequency in populations over time.

If most individuals in a population are young, why is the population likely to grow rapidly in the future?

Many individuals will begin to reproduce soon.

Propose an evolutionary hypothesis to explain the observation that some bird populations do not migrate if people supply food for them in feeders.

Migration is condition dependent in some birds. If enough food is available locally, the costs of migration outweigh the benefits, so the birds fitness will be higher if they stay put.

Journalists must be concise when reporting science news. Why might journalists and the public struggle to understand and discuss ecosystems ecology and global warming?

One reason people have a hard time understanding and discussing ecosystems and global warming is that so many important variables are interacting in complex ways over such large scales.

List the 5 main levels of ecological study, and write a question about the ecology of lionfish that you could research at each level.

Organismal: What range of salinities can lionfish tolerate? Population: What's the growth rate of the lionfish population? Community: How are the lionfish affecting other species in the coral-reef community? Ecosystem: How do lionfish affect the net primary productivity of the coral reef? Global: How will climate change and ocean acidification affect the invasive behavior of lionfish?

Whats the primary threat in marine environments?

Over exploitation

In what populations does exponential growth tend to occur?

Populations that colonize new habitats

Many studies have raised the concern that positive feedback loops among numerous variables in the Amazon will cause a ecosystem tipping point-- a rapid and irreversible transition from forest to grassland. Summarize a possible sequence of effects that could cause a transition from forest to grassland.

Positive feedback loops can cause acceleration of destructive processes. For example. this model shows that increased atmospheric CO2 leads to warmer temperatures and increased droughts, which increases risk of fires, which kills trees, which increases atmospheric CO2 which exacerbates the problem. Climate change, deforestation, and forest fires are combining to greatly increase the likelihood of fires that would destroy the trees and replace them with grasses. Once this tipping point is reached the same processes would maintain the grassland, preventing forest regrowth.

Pythons are generalist predators, consuming a wide variety of prey including birds, mammals ranging from rodents to deer, and alligators. A road survey showed a 99% decrease in the frequency of raccoon and opossum observations within python areas from 2003 to 2011. Rabbits and foxes have also disappeared from the area. Do you think food availability limits, or could limit, the carrying capacity of Burmese pythons in the Everglades?

Since pythons are generalists, it would seem that food availability would not be primary factor in determining the carrying capacity. However, the dramatic disappearance of raccoons and opossums indicates that predation rates are very high and at least some food sources are disappearing. In the long run, the size of the python population will be food-limited.

Temperature forest in China and temperature forest in North America are part of the same biome but are distinct ecosystems..explain

Temperature forests in China and North America are part of the same biome because they're both dominated by deciduous forests and have similar temperature and precipitation profiles. However, the particular species found in each are different due to historical factors making each ecosystem unique.

Scientists predict that global climate change will cause a greater increase in average temperature at higher latitudes than in the tropics. This seems like good news since most of the worlds biodiversity occurs in the tropics. However, recent data suggest that a smaller temperature change in the tropics will cause a larger physiological response in organisms there than the larger temperature change will in organisms in temperate areas. Based on what you have learned about thermal niches in this chapter, propose a hypothesis to explain this.

Temperature is relatively constant in the tropics all year, whereas temperature fluctuates dramatically at higher latitudes. Organisms that are physiologically adapted to constant temperatures may not have as much genetic variation for traits that enable adaptation to higher temperatures. compared to organisms at higher latitudes, which are adapted to tolerate different temperatures at different times of the year.

DNA studies suggest that the lionfish invasion began with the few females released off the coast of Florida, probably from a fish tank. Based on your knowledge of ocean currents, predict the direction in which the lionfish dispersed most quickly.

The North Atlantic Gyre flows in a clockwise direction, so the prevailing current on the Florida coast would be south to north, and it would disperse lionfish up the coast.

What is the main global reservoir of nitrogen?

The atmosphere (N2 gas)

A letter to the editor in a local newspaper asserts that "we cannot afford to preserve natural forests, because we need to use these resources to help humans." How could you respond to this comment in terms of Lyme Disease?

The best prevention for Lyme Disease is to preserve natural forests with high species richness-- when the community is more diverse there will be fewer white footed mice and humans will have lower exposure to Lyme Disease. The forest provides important resources--including health benefits-- to humans when its intact.

Suppose that a two-acre lawn on your colleges campus is allowed to undergo succession. Describe how species traits, species interactions, and the sites history might affect the community that develops.

The exact answer will depend on the location of campus. The 1st species to appear must have good dispersal ability, rapid growth, rapid reproduction, and tolerance for severe conditions. The two-acre plot is likely to be colonized first by pioneer species that have "weedy" characteristics. But once colonization is underway, the course of succession will depend more on how the various species interact with each other. The presence of one species can inhibit or facilitate the arrival and establishment of another

Compare the distribution of the natural terrestrial biomes of eastern North America with the distrubution of anthropogenic biomes.

The natural biome of eastern North America is primarily temperate forest. However, most of this area's now occupied by human-influenced biomes such as cities, suburbs, and farmland.

Why are the open oceans nutrient poor? Why are coastal areas and intertidal habitats relatively nutrient rich?

The open ocean has almost no nutrient input from the land and has little up welling to supply nutrients from fetritus and allows them to reenter the food web/

Pose a hypothesis to explain why the human population has undergone especially rapid growth over the past 200 years. Describe two examples of density dependent factors that limit human population growth. Is it possible that humans have surpassed Earth's carrying capacity?

The population has undergone rapid growth because advances in nutrition, sanitation, and medicine have allowed humans to live at high density without suffering from decreased survivorship and fecundity. Also, human innovations such as machines have enabled the rapid extraction of resources. However, growth will slow more rapidly as density-dependent effects such as disease, famine, and water scarcity increase death rates and lower birth rates. Its possible that human population has already surpassed carrying capacity.

Researchers followed tagged blue whales to observe how they respond to simulated military sonar using sound levels much lower than those typically used during military exercises. Analyze the data below for one individual blue whale and summarize the behavioral effect of the sound exposure.

The whale stopped foraging when the sound started. It immediately surfaced, breathed more frequently, and reduced the depths of its dives.

Why are species like the lionfish considered invasive?

They spread aggressively and displace native species

Evaluate this statement: Species want to increase their fitness by helping friendly species and hurting enemy species.

This statement is incorrect. Unlike individual humans, species do not have conscious thought and cannot make decisions. Species are made of diverse individuals with varying traits. Individuals either succeed or fail at surviving and reproducing under various conditions, including interacting with other species. Over time, the frequencies of traits change in the population.

Explain why it is more energy efficient to eat a pound of tofu than a pound of a hamburger.

Tofu derives from a plant, a primary producer at the base of the productivity pyramid. Cows are primary consumers, one level up. It would be about 10x more efficient to eat tofu, because 10x the quantity of plants would be necessary to provide one pound of beef.

Which of the following types of ecosystem typically has the highest net primary productivity?

Tropical Wet Forest

T/F about inducible defenses? The make efficient use of resources, because they are produced only when needed.

True

T/F about inducible defenses? They result from a coevolutionary arms race.

True

This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by this model. - An increase in CO2 increases the frequency of droughts.

True

This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by this model. - Drought increases the frequency of forest fires.

True

This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by this model. - The death of trees promotes the invasion of grasses.

True

This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by this model. - Tree growth reduces atmospheric CO2

True

This box-and-arrow model summarizes some of the feedback links observed in the Amazon rain forest. Select True or False for the statements that follow, based on whether they are represented by this model. -The burning of fossil fuels increases atmospheric CO2

True

Water depth, water flow, salinity, and nutrient availability are important abiotic factors in aquatic biomes

True

What does species richness refer to? True or False -The number of species in an area

True

True or False: About effects of clear cutting on the Amazon rain forest, then explain your reasoning. -Soil moisture is likely to decline.

True, soil moisture will decline because evaporation from the clear cut land will increase

True or False: About effects of clear cutting on the Amazon rain forest, then explain your reasoning. -Species diversity it likely to decline

True, with the loss of the main primary producers and structural components of the ecosystem, biodiversity will plummet.

Explain why decomposition rates in a field in Nebraska would differ from the decomposition rates in a field in the Amazon. How do decomposers regulate nutrient availability in ecosystems?

Warmer, wetter climates speed decomposition; cool temperatures slow it. Decomposition regulates nutrient availability because it releases nutrients from detrius and allows them to reenter the food web.

Explain why biologists want to maintain Habitat Corridors that connect populations in metapopulation, and unoccupied habitat that is appropriate for the species in question?

a.) Corridors allow individuals to move between populations, increasing gene flow and making it possible to recolonize habitats where populations have been lost. b) Maintaining unoccupied habitat makes it possible to recolonize the habitat.

In some circumstances, the use of probiotics, which stimulate the rapid growth of bacteria that are mutualistic or commensal with humans, can eliminate the need to use antibiotics, which can wipe out helpful bacteria along with harmful bacteria. The use of probiotics is an example of which process?

competitive exclusion

What do proximate explanations of behavior focus on?

genetic, neurological, and hormonal mechanisms of behavior

The relationship between corals and the photosynthetic protists they harbor is an example of:

mutualism

What is niche differentiation?

the evolution of traits that reduce niche overlap and competition