Title: Need help with extra credit Post by: chokherbali on Nov 29, 2013 I have got this extra credit question and I have no idea how to solve it. I will get five points of extra credit if I can answer it which will boost my grade to an A. So someone please help solve this problem. The question is written below:
1. You have been studying an herbivorous lizard species, desert iguana, and an herbivorous turtle species, desert tortoise, at 10 sites in the Mojave Desert of Southern Nevada. An older publication reported data on 50 study sites in Southeastern California showing the following: at all 50 of their study sites, desert iguanas and desert tortoises predominantly ate herbaceous species of grasses and forbs; in 48 sites, desert iguanas and desert tortoises appeared to coexist; and finally, at the two sites where the lizards and tortoises did not coexist, the lizards typically came to population sizes of 65 desert iguanas per square kilometer. From data from your study, you found two results: the competition coefficient for the effect of iguanas on tortoises appears to be 0.32, and when either species (tortoises or iguanas) reaches a density of 300 (or more) individuals per square mile, the other species always appears to be prevented from increasing regardless of its population density. At another study site in Southern California, a predator from the family Corvidae (the common raven) is found in syntopy with desert tortoises only. Others have determined that ravens require prey densities of desert tortoises in excess of 38 tortoises per square kilometer before the raven population can increase. Your data on this system has allowed you to determine that ravens can kill baby tortoises at a rate of 0.5 tortoises per raven per year. The normal death rate of ravens is 0.1 raven per raven per year. Finally, you have determined that the carrying capacity of desert tortoises in California is the same as that in Nevada. Assume for the sake of analysis that the populations exactly obey Lotka- Volterra equations. Show all of your work, but also summarize your answers in one sentence for each question. A. What population densities for desert iguanas and desert tortoises would you expect in Nevada, if the other competitor were driven to extinction? B. What are the predicted population densities of the two coexisting species when they reach equilibrium population numbers? C. What would happen if tortoises had a carrying capacity of 500? D. Can tortoises coexist with ravens? E. What is the carrying capacity of ravens when tortoises are not present? Title: Re: Need help with extra credit Post by: Arquimedes on May 6, 2014 Hey Beth I hate spicy food, so no, even with the green chiles, they aren't spicy. You could add joepnalas, if you want them spicy. They were really good. It's a good thing to do with those cheap chicken breasts that I told you about. I really couldn't believe I got an entire pan of food out of just two breasts.
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