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Important information about Ecology

14. A. In developing the formulas for population growth I made specific assumptions about birth rates and death rates. On the graph below draw the line that relates birth rate to population size if the environment were perfect and thus the population is growing at its biotic potential. Also, draw the line that relates birth rate to population size if the environment were real and food is limited and thus the population is growing according to the logistic formula. Be careful, these are NOT population growth curves! Label your lines as "perfect" and "real"! (See graph in attachment)

B. Even though a species is growing logistically, it rarely does so with a smooth growth curve that levels out at the carrying capacity like the formula indicates it should. Instead, the curve fluctuates and looks jagged rather than smooth. Briefly describe two reason why the actual growth curve for such a species is jagged and doesn't smoothly level out at the carrying capacity (look at the curve for questions 1-4).

15. Describe how either a social hierarchy or territoriality can regulate population size in a density-dependent manner.

16. What is the difference in the way data are collected for a cohort life table compared to a static life table?


Solution Preview

14.a. This question asks you to first draw the birth rate in regards to the population size. (See attached for diagram)

In an ideal situation the birth rate remains the same as the population grows. Without limits on resources or crowding effects there is no detriment to the birth rate. With the constant birth rate the population will grow at an exponential rate. In a real environment external factors such as competition for limited resources and the stress effects of crowding have a negative impact on the birth rate decreasing the number of young ...

Solution Summary

This solution is comprised of a detailed response to concepts of social/territorial hierarchy, cohort life and static life which is enclosed within an attached Word document.