Question

resource availability affects populations of organisms in an ecosystem. other factors such as predators, disease, and weather can also cause changes to populations as well. evaluate the graph showing the population of moose over time. infer possible explanations for changes in the population? choose all that apply
a the moose had abundant food and limited predators in 1970.
b the carrying capacity of the moose population is around 600.
c the carrying capacity of the moose population is around 800.
d there was most likely an increase in predators from 1980 - 2000.
e in 1990, some sort of catastrophic event caused the death of more than half the moose.

Explanation:

• Option A: In 1970, the moose population was at 800. Abundant food and limited predators would allow a population to be at a high - level, so this is a valid explanation.
• Option B: The carrying capacity is the maximum number of a species that an environment can sustain. The population does not stay around 600 consistently enough for 600 to be the carrying capacity.
• Option C: The population was at 800 in 1970, but then it decreased. If 800 were the carrying capacity, we would expect the population to stabilize around 800.
• Option D: From 1990 - 2000, the population increased. An increase in predators would likely cause a decrease in the moose population, so this is not a valid explanation.
• Option E: In 1990, the population dropped from around 600 to 300 (more than half), which could be caused by a catastrophic event.

Answer:

A. The moose had abundant food and limited predators in 1970; E. In 1990, some sort of catastrophic event caused the death of more than half the moose.