Exam 58: Dynamics of Ecosystems

Choose the letter of the best match from the following: -Organisms are interrelated;energy transfers through the various trophic levels;there are a low number of herbivores,which are supported by much larger numbers of photosynthesizers.

A Viceroy caterpillar feeds on a leaf.If a day's feeding gains the caterpillar a total of 1000 calories and 50% is lost in its feces and 33% of the energy is used through cellular respiration,how many calories of the original intake are available for caterpillar biomass?

What feature do the carbon and phosphorus cycles have in common?

Photosynthesis fixes about

All of the following undergo biogeochemical cycles except

Which of the following terms could be used by you as you explain to your teacher your understanding of the total amount of organic matter produced in a community in a given time that is available for heterotroph consumption?

Which one of the following ecosystems is most likely to show an inverted biomass pyramid but a normal energy pyramid?

All of the following factors except one affect species richness.Select the exception.

Which one of the links in the food chain shown below does the garden spider represent? Grass-cricket-garden spider-blue jay-red-tailed hawk

In a pond ecosystem,a crayfish feeds on three species of algae.It in turn is preyed on by one species of fish and a heron.The heron also preys upon the fish.What is the minimum number of food chains in this food web?

With almost no exceptions,the nitrogen fixers are

Factors that could determine productivity of an aquatic community include all of the following except

Heterotrophs must obtain organic molecules that have been synthesized by _____________.

Which one of the following explanations for why the tropics have greater species diversity than the temperate zone is least convincing?

The balance between photosynthesis and ___________ is altered by the combustion of fossil fuels.

__________ becomes available to organisms almost entirely through the metabolic activities of a few genera of bacteria.

Choose the letter of the best match from the following: -All of the organisms that live in a place,together with the physical characteristics of the place;they interact with each other in a dynamic fashion.

What feature do the carbon and nitrogen cycles have in common?

In a food chain with four trophic levels,what would be the energy in the top trophic level if the energy contained in the primary producer level is 40,000 kcal/m²/yr? Assume a trophic level transfer efficiency of 10%.

Experimental studies with watersheds,such as the one of Hubbard Brook,show that trees and shrubs in an undisturbed ecosystem will help in