Interpreting Ecological Data - Answer Key

Graph 1: Rabbits Over Time

a. The graph shows a _______S Shaped___ growth curve.
b. The carrying capacity for rabbits is ___~65___
c. During which month were the rabbits in exponential growth? June

Graph 2: Average Toe Length

a. In 1800, about how many people surveyed had a 3 cm toe? ____~58___
How many in 2000? __~10
b. The data shows the ______Stabilizing___ selection has occurred?
c. In 2000, what is the average toe length? ___~4.5___ What is the average toe length in 1800?

Graph 3: Mexico and US

a. In Mexico, what percentage of the population is between 0-4 years of age? ___16____ In the US? ____7__
b. Which population is growing the fastest? Mexico_
c. Which age group has the smallest number in both countries? ___80+__

Chart 4: Trapping Geese

In order to estimate the population of geese in Northern Wisconsin, ecologists marked 10 geese and then released them back into the population. Over a 6 year period, geese were trapped and their numbers recorded.

a. Use the formula to calculate the estimated number of geese in the area studied? 60(10) / 6 = 100

b. This technique is called Mark & Recapture
c. Supposing more of the geese found in the trap had the mark, would the estimated number of geese in the area be greater or lesser? less (bottom number would be greater in formula)

Chart 5: Mushroom Plots

Another ecologist uses a different method to estimate the number of mushrooms in a forest. She plots a 10x10 area and randomly chooses 5 spots, where she counts the number of mushrooms in the plots and records them on the grid.

a.Calculate the number of mushrooms in the forest based on the grid data: Average per grid = 5, 100 plots; total = 500
b. Thie technique is called ____Random Sampling__

Chart 6: Snakes & Mice

The data shows populations of snake and mice found in an experimental field.

a. During which year was the mouse population at zero population growth? __2000, closest to zero__
b. What is the carrying capacity for snakes ? ~14
c. What is the carrying capacity for mice? _~550-600_
d. What is the rate of growth (r) for mice during 1970? ___+500__ During 1980? ___-100__