Biology, Eighth Edition (Raven)

Chapter 57: Dynamics of Ecosystems

Post Test

1
Why is the nitrogen cycle particularly complicated? (p.1193 )
A)It involves more steps than the other cycles.
B)Nitrogen is used in so many compounds in an animal's body.
C)Because bacteria are involved in some stages.
D)Because it involves multiple changes in the chemical form of nitrogen.
E)all of the above
2
How is it possible to get an inverted pyramid of biomass (e.g. biomass of copepods greater than that of algae)? (p. 1201)
A)It is not possible.
B)It's possible if each individual primary producer is very rich in energy.
C)It's possible if the system is very productive and the primary producer is consumed as it is produced.
D)This is the usual condition.
3
Why would increasing the amount of sunlight increase carnivore biomass? (p 1205)
A)Carnivores would be able to see their prey better.
B)It will increase the amount of energy, and therefore the amount of biomass, in the system.
C)There will be a smaller percentage of energy wasted in the system.
D)both a and b
4
Why is species richness thought to contribute to ecosystem stability? (p. 1205 - 1206)
A)It can lead to greater productivity.
B)It makes the ecosystem more resistant to invasion by new species.
C)The proportion of predators will be lower.
D)both a and b
E)all are plausible
5
Using the theory of island biogeography, predict the number of species you would find on a small island near the mainland versus the number of species on a large island far from the mainland. (p. 1208)
A)The large island would have more species.
B)The small island would have more species.
C)They would both have approximately the same number of species.
D)It would depend on the actual sizes of the islands and their actual distances from the mainland.
E)The actual rates of colonization and extinction would have to be known.
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