What is survivorship?
What does a survivorship curve show?
Explain what the three survivorship curves tell us about humans, squirrels, and clams.

When wild plant and animal populations are logged, fished, or hunted, only the oldest or largest individuals tend to be taken. Many of the commercially important species are long lived and are slow to begin reproducing. If harvesting is not regulated carefully and exploitation is intense, what impact does harvesting have on a population's age structure? How might harvesting affect the population's life table and growth rate?

Demographic momentum refers to the tendency for

a. Low population growth rates to continue to decline

b. High population growth rates to continue to increase

c. Populations to continue to grow in number even when growth rates reach zero

d. Populations to continue to grow in number even when women are reducing the number of children they bear

e. Women to continue to have children even though they no longer wish to

What are some factors that might have a density-dependent limiting effect on population growth?

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Burmese pythons (Python molurus bivittatus) are constricting snakes that can reach enormous sizes (up to 7 meters in length). They are native to Southeast Asia but were released into southern Florida from the pet trade. Many other snakes occur naturally in this area. Are the introduced pythons a problem?

Burmese pythons were first found in the wetlands of Everglades National Park in the 1980s, but only rarely. The accompanying graph shows what happened next. Most of the data are derived from chance encounters of pythons on roads (pythons are notoriously difficult to find). How would you describe the type of population growth in pythons from 2000 to 2008?

a. Logistic

b. Exponential

c. Linear

d. Logarithmic

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Burmese pythons (Python molurus bivittatus) are constricting snakes that can reach enormous sizes (up to 7 meters in length). They are native to Southeast Asia but were released into southern Florida from the pet trade. Many other snakes occur naturally in this area. Are the introduced pythons a problem?

Researchers hypothesize that the severe winter of 2010 caused the decline in the number of pythons encountered that year. Is cold weather typically a density-dependent factor or a density-independent factor? Explain the difference.