What would happen to an ecosystem without decomposers? since some bacteria are decomposers, which fill an important role in the food web.
a. Autotrophs would take over the role of decomposers
b. All levels of the food web would be affected because it would be difficult to recover nutrients from dead matter and waste
c. Consumers would be most affected because decomposers are the main source of energy
entering the food web.
d. Primary producers would increase because of the excess nutrients available.
A wetland area is a fully functioning ecosystem that contains a diversity of plant, insect, and animal populations. Which of the following ecosystem services does this wetland most likely provide?
I. Clean water
II. Nutrient control
III. Soil preservation
I and II only
II and III only
I, II, and III
The island biogeographical model can be described by which factor?
a. Dispersing species are more likely to find smaller secluded habitats
b. Migrating species are more likely to find larger habitats over smaller ones
c. Smaller populations are less likely to go extinct
d. Large islands have less available niches for immigrating species
How do you expect the population trends to change after 2009 if changes in the aquatic environment make dark brown sea lions more reproductively successful than sea lions with light brown coats?
a. The percentage of dark brown sea lions will increase, and the percentage of light brown sea
lions will decrease.
b. The percentage of light brown sea lions will increase, and the percentage of dark brown sea
lions will decrease.
c. The percentages of both dark brown and light brown sea lions will increase.
d. The percentages of both dark brown and light brown sea lions will decrease.
Pollution in an ocean ecosystem has caused a significant drop in sea otter population. Within a year, scientists monitoring the ecosystem note that the sea urchin population on which the otters feed has greatly increased. The prevalence of sea urchins has caused the kelp and algae populations on which the urchins feed to decrease. The scientists fear the urchins will also begin to overwhelm the ecosystem’s fragile coral population. Which species is most likely the key stone species in the ecosystem?
c. Sea star
d. Sea urchin
When there are more organisms in a population than the ecosystem can sustain, this
is known as a
a. biological capacity
b. biological surplus
c. carrying capacity
d. carrying surplus