Exam 44: Ecological Communities

Daniel Simberloff and Edward O.Wilson tested the theory of island biogeography by first removing all arthropods from a group of mangrove islands and then measuring the recolonization of the islands over a two-year period.Which result did they not observe?

Two 1-km² areas of mature forest are at the same latitude.Area A is surrounded by developed land with housing and shopping centers.Area B is in the center of a 100-km² conservation area of mature forest.A team of scientists does surveys to determine the diversity of arthropod species in both areas.Which area will likely show greater species diversity,and why?

Which statement best describes the changes in the biological community of Krakatau since the volcanic eruption?

Coral reefs are found in tropical waters around the world,some on islands far from large landmasses.They are the most highly diverse ocean ecosystems,equivalent in their diversity to tropical rainforests on land.How might organisms arrive to build and colonize coral reefs,and how does coral reef diversity become so great?

After a large-scale disturbance,such as a volcanic eruption or a major hurricane,

A large lake in a relatively isolated environment has had clear water and a stable,moderately diverse species composition for hundreds of years.When the region is developed into farmland,the lake begins receiving large amounts of fertilizer runoff,making it turbid and highly eutrophic (excessively rich in nutrients).The species composition becomes much less diverse and is made up of species that tolerate low oxygen.Even after the farmland is abandoned and fertilization stops,the lake remains eutrophic.This is an example of a(n)

Until the mid-1960s,dung from introduced cattle accumulated in Australia because

Bumblebees live in nests in loose soil on the ground,in areas with little vegetation.However,they must be near vegetated areas,where they feed on and pollinate many flowering plants.This information describes the bumblebee's

A community ecologist would most likely study

Based on information in the graphs below,explain how species richness is related to number of functional groups in a community,and how they both relate to net primary productivity (measured as plant biomass per unit time).

Three plant communities have the species composition shown in the table below.Which community or communities have the highest species evenness?

In a microbial community,autotrophs generate 1,000 calories per hour of GPP and 500 calories per hour of NPP.Primary consumers convert 60 calories per hour into their own biomass.What is the ecological efficiency in the link between autotrophs and primary consumers in this community?

Use the following to answer questions : Refer to the graphs below showing data from the studies of David Tilman and colleagues on the effect of species diversity on net primary productivity in prairie ecosystems. -Based on the data in the two graphs,how can the effects of species richness and number of functional groups (niches)on NPP best be described?

Suppose that in a study of an ecological community,NPP increases as species richness increases,but scientists find no relationship between NPP and the number of functional roles played by the species.Which conclusion could be inferred?

Grain is eaten by cows,and cows are eaten by humans.If the ecological transfer efficiency between each trophic level is 10 percent,how much grain is required to produce 70 kg of human biomass?

The diagram below shows changes in species composition for the first year after recolonization of mangrove islands that were defaunated (had their arthropod species removed).One hypothesis proposed for recolonization was that every island has a specific set of niches,and recolonization will be complete when the original set of species filling those niches has been reassembled.Do these data support that hypothesis? Why or why not?

As climate change continues,average temperatures are increasing at all latitudes and spring is beginning two to three weeks earlier in many areas.How will these changes likely affect plant communities?

To minimize ecosystem damage due to fragmentation,ecologists can increase colonization by locating habitat fragments close together,keeping some large patches,and creating _______ to connect patches.

The loss of a single species from a community will most often affect community function by affecting the community's

The first naturalist to observe and remark on the relationship between species richness and latitude was