SHW - Pg. 5

Name____________________________ Period _______
Date____________________

CH. 52: POPULATION ECOLOGY

1. How can an ecologist estimate the numbers of individuals in a population?
- Using the density and dispersion of the individuals in a population, an ecologist can estimate the numbers of individuals in an area. Or they can use the mark-recapture method.

2. What are some possible difficulties in counting populations?
- Counting is impractical b/c the organisms may be constantly moving, dying, or reproducing.
- Estimation is not accurate, because the dispersion of individuals may vary in certain locations.

3. Describe the patterns of dispersal.
a. Clumped - individuals aggregate in patches
b. Uniformed - individuals are evenly spaced
c. Random - the position of each individual is independent of the others, and spacing is unpredictable.

4. Compare the survival strategies of species and give an example of each type.
a. Type I curve is relatively flat at the start, reflecting a low death rate in early and middle life, and drops steeply as death rates increase among older age groups. (Ex. Humans)
b. The Type II curve is intermediate, with constant mortality over an organism’s life span. (Ex. Squirrel)
c. A Type III curve drops slowly at the start, reflecting very high death rates early in life, then flattens out as death rates decline for the few individuals that survive to a critical age. (Ex. Oysters)

5. Write the formula for population growth without limits. Define the terms.
- DN/Dt = B - D where B is the number of births and D is the number of deaths.
If N represents population size, and t represents time, then DN is the change is population size and Dt is the time interval.