Introduction of a toxicant to an ecosystem
Course:- Other Subject
Length: word count:1800
Reference No.:- EM132187206

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Q1. Periodic episodes of meadow lark mortality are noted near an agricultural field. The field was used for many years to grow cotton and, consequently, has a history of DDT and lead arsenate application. At present, carbamate pesticides are periodically applied to the fields.

How would you determine which, if any, of these potential toxicants are producing the mortality?

Q2. a. What quantitative models (approach) would you use to predict the joint action of two pollutants with identical modes of lethal action? Explain.

b. Which model (approach) would you use for the joint action of two toxicants with completely different modes of lethal action? Explain.

c. How would you determine whether their joint effects were additive or non-additive?

Q3. You would like to study the impact of a contaminant on a songbird species nesting in a contaminated location. Describe your approach.

Q4. Using the principle of allocation and concept of strategy, relate how life histories of individuals in a population may shift in response to a pollutant.

Q5. a. In general, how would a log normal, species abundance curve change with the introduction of a toxicant to an ecosystem? What is (are) the possible mechanism(s) for this shift in the curve?

b. Would there be a different impact with different types of pollutants? Give examples.

c. How could a community successfully avoid irreversible damage from the pollutant(s)?

Q6. a. Assuming that the MacArthur-Wilson model accurately reflects colonization, predict the number of species inhabiting a beach devastated by an oil spill if the number of species originally on the beach was 23 (SEQ = 23?), G = 0.10 (units of years), and 10 years has passed since the devastation occurred. How long would it take for 95% of the species to reestablish themselves? Would the community (species assemblage) be back to normal at that point?

b. Would you pick the same approach (MacArthur-Wilson model) for the above issue? What would be some alternatives? Why or why not?

Q7. a. Describe the rivet popper hypothesis versus the redundancy hypothesis debate.

b. What is the significance of this debate relative to assessing an adverse effect of pollutants to the environment?

c. How might the application of these hypotheses change for the prediction of toxicant effects in a metacommunity context?

Q8. Give three reasons why the traditional ecosystem context should be expanded to a larger scale in order to address environmental problems facing us today. What could be an issue(s) if you only look on a large scale?

Q9. a. The NYT article "The Insect Apocalypse Is Here" identifies some problems we discussed in class regarding environmental studies. Please discuss these problems.

b. What do you think are potential causes for the Insect Apocalypse?

c. Should we be worried?

Q10. Now that the holiday season is upon us a lot of people feel that they have to get the latest and greatest in technology (a new tablet or smartphone for instance, although I notice more "buy a car for the holidays" commercials...). What are some, at least four, environmental impacts (small and large scale) related to these devices? Maybe these impacts are similar as for those cars?

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    THIS EXAM IS DUE ON TUESDAY 11,- no exceptions, any response posted after this date will not be graded. Please e-mail me with any questions you may have. You may use books, articles, and any reputable scientific references - including the internet (no Wikipedia!) - to answer these questions. You must cite the references you used at the end of the exam. You are not to discuss this exam with any other student in or out of the class.

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