Population Ecology

Front

A population of mosquito larvae is living in a large pond. Mosquitofish are a type of fish that eat mosquito larvae. What is a direct effect on the mosquito larvae population when mosquitofish are introduced?

Back

deaths increase

Front

What would increase the size of a population of cardinals in a forest?

Back

an increase in the birth rate of cardinals

Front

The graph shows changes that occurred in the size of a population of animals over a year. Which of the following is best supported by the graph?

• Between month 1 and month 5, the immigration rate was zero.
• Between month 4 and month 6, a predator was introduced into the ecosystem and increased the death rate.
• Between month 5 and month 7, the birth and emigration rates decreased and the death and immigration rates increased.
• Between month 8 and month 12, the birth and immigration rates equaled the death and emigration rates.

Back

Between month 8 and month 12, the birth and immigration rates equaled the death and emigration rates.

Front

A small population colonized an isolated island. Over time, the size of the population increased to its carrying capacity, as represented in the graph. Which condition will most likely keep the population at its carrying capacity?

• a death rate of zero
• a death rate that is half the birth rate
• a death rate equal to the birth rate
• a death rate that is twice the birth rate

Back

a death rate equal to the birth rate

Front

Pheasants' population growth slowed after initial increase from 8 to 2,000. Why?

Back

Competition for resources increased, which increased the death rate.

Front

What caused a decrease in the size of a bear population when individuals moved to another area?

Back

emigration

Front

Expression to calculate the change in the size of a population: (births + deaths) + (immigrants – emigrants), (births – deaths) + (immigrants – emigrants), (births – deaths) + (immigrants + emigrants), (births + deaths) + (immigrants + emigrants)

Back

(births – deaths) + (immigrants – emigrants)

Front

In a certain population, the death rate is greater than the birth rate from year 1 to year 2, and the immigration rate equals the emigration rate. Which of the following graphs represents this information?

Back

Front

What most likely happened as a result of the arrival of brown tree snakes on Guam?

Back

Many bird populations disappeared.

Front

Based on the graph data, what change most likely occurred in the wolf and moose populations from 1990 to 2000?

Back

The wolf population increased and the moose population decreased.