chapter 53 population ecology

A population of snails is located in a lake that has a carrying capacity of 20,000 snails. The intrinsic capacity for increase for these snails is 0.15 and the current population is 12,000. In a year, how big do you expect the snail population to be?

12720

Note how quickly populations can grow even with per capita growth rates that are less than 1. Once you've set different parameters for starting population size and per capita growth rate, set your starting population size to 100 and your per capita growth rate to 0.5. What is your population size at time 7?

3,312 (with margin: 0)

A population of 3000 starfish has a yearly per capita population growth rate of 0.012. A year from now, how big will the population be? Assume that the population grows exponentially according to the equation

3036

Now with your starting population at 100, change your per capita population growth rate r to 0.6. Now what is your population size at time 7? Note how even small changes in r can have profound effects on growth rate. You Answered

6,669 (with margin: 0)

What is the carrying capacity for this population of whooping cranes?

>325

For populations that grow exponentially (d N d t = r N): which of the following populations will experience the fastest population growth rate?

A population of 1000 rabbits that has a yearly death rate of 0.01 and a yearly birth rate of 0.11

A population of 2000 starfish has a yearly per capita population growth rate of 0.012. By next year, how do you expect population size to have changed? Assume that the population grows exponentially according to the equation d N d t = r N

It will increase by 24 starfish

For populations that grow exponentially (d N d t = r N): given a per capita growth rate of 0.1, which of the following populations will have the most rapid population growth?

One with 1000 individuals

Which population should display the highest growth rate?

One with a high birth rate and a low death rate

Which of the following statements is correct about the graph of exponential population growth shown here?

Over time, the population size gets bigger and the rate of population growth becomes faster.

What does a negative per capita population growth rate tell you about a population?

The population size is decreasing instead of increasing.

If the carrying capacity for the North Atlantic cod on the Grand Banks of Newfoundland is 500,000 tons, when do you expect that the rate of population growth would be greatest?

When there are 250,000 tons of cod on the grand banks

Under what conditions would a population grow slower than predicted by exponential growth?

all the above

A population of flamingoes in Florida grows according to a logistic model, with r = 0.17 and K = 10,000. Which of the following statements are correct? Check all that apply.

dN/dt is lower at N=200 than it is at N=5000 dN/dt is lower at N=9000 than it is at N=5000 dN/dt will be negative if N = 12,000

The carrying capacity for creole wrasses on a reef is limited by the amount of zooplankton prey available. On one reef, there is an increase in zooplankton over a 10-year period. Over this period, the reef's carrying capacity for creole wrasses will...

increase

A population of snails has an annual per capita birth rate of 0.055 and an annual per capita death rate of 0.015. Calculate an estimate of the change in population size over one year, for a given starting population of 1,000 individuals. Assume that the population grows exponentially according to the equation

increases by 40 individuals

A population of deer in Florida grows according to a logistic model, with r = 0.17 and K = 10,000. At what population size is the per capita population growth rate the highest?

n=1000

In logistic growth, population growth will be 0 when...

n=k

In the logistic population growth model,

population growth rate is slow when N is small and when N is close to carrying capacity

Compared to exponential growth, what happens as the population size grows and approaches nears carrying capacity?

population growth rate slows down

Based on the following equation of population growth: d N d t = r N a population will be stable over time when...

r=0

An ecosystem has a carrying capacity of 1,000 individuals for a given species, and 2,000 individuals of that species are present. The population...

size will decrease

On your first day as a wildlife biologist for a national park, you are told that yearly changes in the size of the wolf population in the park can be modeled with the following equation, where N is 120 and r is -0.05. d N d t = r N You conclude that:

the population is declining, and you expect to have ~114 wolves in the park next year

Population ecologists are primarily interested in

understanding how biotic and abiotic factors influence the size of groups of interbreeding individuals.