Biology - What would happen if decomposition stopped

Biology Question

Assignment 4: Ecology

1) What would happen if decomposition stopped? Answer in 1-2 sentences, referencing a physical law we discussed in class. (2 points)

2) Biological systems can be important carbon sinks, taking some of the excess CO2 released by humans out of the atmosphere. If a manager wanted to understand how much CO2 was being stored in a given area to determine what regions to focus on for protection, should they look at average Net Primary Productivity (NPP) or average Net Ecosystem Productivity (NEP) in a given area? Explain your choice.

(2 points).

3) Imagine you conducted a mark-recapture study to estimate the number of turtles in a wetland. You marked 30 individuals in the first year of the study. You returned the second year and captured 100 individuals, of which 2 were re-captured marked individuals.

a. Estimate what the size of the population is, assuming all of the assumptions of the mark-recapture estimate are true. Make sure to show your work (1 point).

b. You realize, after doing the study that 30 of the individuals captured in the second year were juvenile turtles, born after the first round of marking. Does this study still meet the assumptions of mark-recapture? Do you think your initial estimate is overestimating or underestimating the population?

 (2 points)

4) The Sage Grouse (a type of bird) mates through lek mating, where a few males mate with most of the females, and many males will not mate at all. Knowing this, if you were in charge of setting hunting regulations designed to keep the number of new Sage Grouse being born each year as high as possible, would you allow hunting of only males, only females, or both male and females? Briefly explain why.

(2 points)

5) Imagine a food chain with grasses that are consumed by rabbits, that are in turn preyed upon by coyotes, which are hunted by humans.

a. Given this food chain, what would you predict would happen to the population densities of coyotes, rabbits, and grass if humans stopped hunting coyotes? Why would you predict this? (2 points).

b. If owls, a second predator species, entered this community and started hunting rabbits, what would you predict would happen to the population size of coyotes? What type of interaction characterizes that between the coyotes and owls? (2 points)