Population Ecology

Your roommate left the potato salad out on the counter overnight, but is happily eating it for breakfast. "We learned that bacteria take 20 minutes to reproduce," he explains, "so I figure at most there's only a couple hundred in there. No big deal." What is your response?

"There might be millions of bacteria in there! They have been growing exponentially all night."

A cruise ship full of people crashes onto an island, and they are not contacted by the outside world for 100 years. The resulting island population depends on the demographics of the people on the cruise ship. For each scenario, match the demographic feature that would be limiting for the growth of that population. 1. a cruise that happened to be carrying a large supply of birth control 2. a cruise full of cancer patients 3. a male-only cruise 4. a cruise full of retirees age structure sex ratio mortality rate fecundity

4 3 2 1

What would be a good example of a density independent factor?

An unusually cold winter

Salamanders are very sensitive to dessication and are often found under rotting logs in a forest. If you were walking in a forest what type of distribution pattern would you expect to observe?

Clumped

On average, individuals of a grassland butterfly population live for three months, reproduce once per lifetime, and lay approximately 100 eggs per brood. Given this information, indicate if the following statements are true or false? a. If predation caused the average lifespan of the butterflies to decrease to two months, the population would likely grow. b. If the butterflies began to reproduce three times per lifetime but laid the same number of eggs per brood, the population would likely grow. c. If the butterflies began laying 200 eggs per brood, the population would likely grow.

False. When the mortality rate of a population increases, the population size is likely to decrease. True True

Which of the following explains why you might expect the number of individuals in a population to increase exponentially but you should expect the number of tables that a carpenter produces to increase linearly?

Organisms can make more organisms, but tables cannot make more tables.

A wealthy but eccentric environmentalist has purchased an uninhabitated island wilderness. "I'm not letting people on the island," he says, " so the populations on the island will stay the same, acting as a perpetual time capsule of how it is today." What could interfere with his plan to keep the island unchanging? (Check all that apply.)

bad weather climate change dispersal of seeds onto the island immigration or emigration of mobile species

Check each of the following investigations that would be considered demographic studies.

measuring the death rates of Switzerland vs. Nigeria measuring the number of ladybugs reproducing at a particular tree every spring investigating whether children born in the current decade are likely to live longer than those born in the previous decade

What determines the carrying capacity of an environment?

the availability of resources in the environment