# New And Precise Earths’Ecosysterm

New And Precise Earths’Ecosysterm

Test #2 REWRITES 30 March 2018

ECS 111 Name:______________________________________

Answer question(s) of your choice. For the rewrite, you need to include appropriate references. References must be in the format given in the writing guide. Avoid blogs and other non-permanent references. In considering question five (5), consider the equilibrium states for P and what they mean to the yield. From the point of view of the math, you should be able to work out the equilibria (there are three, the null state P=0 and two possible P >0.). Then analyze the Y for them. In essay form or you should discuss the results.

1) Discuss in simple terms the relationships between soil types/profiles and the biomes in which they are found. How do these and water availability influence agriculture?

2) Describe your favorite animal, its geographic range, and current status (sustainable, endangered, or threatened).

3) Discuss the concept of land ownership. What is the role of government in terms of ownership of land and resources? (Here you may pick a system or contrast a set of government systems.) Give some examples of issues involved either in the past and/or at present.

4) There is major concern over the future of tropical rainforests. What are the issues involved with this debate? What are the explicit ecosystem problems with forest use? Include a discussion of the fate of disturbed forest areas.

5) Consider a population of insect pest, P, potentially infesting a particular area, A, of agricultural land. If the population equation for the insect is then

dP/dt = r P (1-P/αA) – δ A,

where r is the maximum rate of growth in P, α the carrying capacity per area, and δ the damping over an area by application of insecticides.

Now the financial yield, Y, on the crops is reduced by the pest such that the yield equation is

Y = β ( A – γ P).

where β=βo – c δ, reflecting both the crop damage reduction of the gross production, γ P, and the cost involved with insecticide treatment, cδ

Discuss the repercussions (effects) of the pest on farm income in this situation. What are the larger implications that arise in these situations?

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