Biology 5868 ID Exam 3 May 10, 2007

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1 Ecotoxicology Name KEY Biology 5868 ID Exam 3 May 10, 2007 Be as specific as possible for all answers. Most of the questions have multiple parts; make sure to answer each part! Use diagrams, flowcharts, and formulas where appropriate. Use the back of the pages if necessary (make sure to indicate the question being answered). Very Short Answer. (1 point per answer) 1. Resistance to toxicants that is acquired through the actions of many genes is referred to as vertical resistance. True or False? (1) 2. List one direct effect and one indirect effect of contaminants that result in changes in gene frequency. (2) direct - selection-associated changes indirect - genetic drift, genetic bottleneck, genetic diversity (heterozygosity) 3. Calculating relative risk involves comparison of prevalence in two populations. True or False? (1) 4. List a bioindicator that would be appropriate for assessment of contaminant effects on communities. (1) structure, diversity, competitive interactions, predation, energy transfer, successional states 5. What does a dominance index measure in a landscape-scale context? (1) how much of a landscape is occupied by a single ecosystem 6. List one structural indicator for a community-scale, ecosystem-scale, or landscape-scale assessment. (1) diversity, keystone species, indicator species, sentinel species, r- v. k-strategists 7. List one functional indicator for a community-scale, ecosystem-scale, or landscape-scale assessment. (1) production, community respiration, nutrient cycling 8. List two requirements for a metapopulation to exist. (2) patchy habitat, uneven distribution, minimal viable populations, migration, 9. GIS stands for: (1) geographical information systems 10. Groundwater below a closed landfill has been contaminated by chemicals, which are expected to enter streams within two years. You perform an ecological risk assessment. Is it predictive or retroactive? (1) 11. I (will/will not) watch Al Gore s movie An Inconvenient Truth very soon. (1) Definitions Define any five of the following terms. (3 points each) 12. Ground-truthing verification of remote sensing or GIS data by field visits 13. Emergent properties properties of complex systems that are not predictable from the properties of the individual parts making up the system 14. Finite rate of increase population growth under actual environmental conditions 1

2 15. Rivet popper hypothesis individual species of a community can be eliminated by stressors until a certain point, after which further stress will cause catastrophic failure of the community 16. Keystone species a species that is vital for the maintenance of a community 17. Ecotone an edge of an ecosystem or habitat; usually richly diverse and with high abundance 18. Carrying capacity the number of organisms that a given ecosystem/habitat can support without that number increasing or decreasing Short Answer. Answer any five of the following questions. Note - describe requires more than simply listing answers. (6 points each) 19. Why are logical rules of inference necessary for evaluating epidemiological evidence? Epidemiological evidence often provides only weak inferential connections between observed ecotoxicological effects and possible causes. Assessing such data using strict logical rules of inference helps to determine whether the inferred associations are plausible and probable, thus reducing uncertainty. 20. Describe the rescue effect involving contaminant effects in a metapopulation. If a stressed metapopulation contains at least one subpopulation (patch) that is not affected by the stressor (contaminant), it can act as a source for contaminated, depopulated patches (i.e. sinks) through migration. Therefore, populations in stressed patches have a lower probability of extinction if the metapopulation contains unstressed patches than if all subpopulations are stressed. 21. Define R 0 (net reproductive rate). Why is R 0 significant for determining population stability? What does an R 0 of 0.72 imply for the future of the population? R 0 = number of female offspring that a newborn female will produce during her lifetime R 0 must be sufficient to ensure that the breeding ability of the population is retained through future generations R < 1 indicates a shrinking population 0 2

3 22. A certain contaminant is known to be lethal to some, but not all, species of a hypothetical community. Compare the expected makeup of that community after contaminant exposure in terms of the number or proportion of r-strategist and k-strategist species. Justify your answer. A well established community might be expected to have a large number of k-strategist species, which reproduce relatively slowly and in low numbers, and fill virtually all available niches. After a contaminant eliminates many species over many niches, the empty niche-spaces are likely to be filled with a smaller number of r-strategist species, which are opportunistic, reproduce quickly, and have large numbers of offspring. 23. Risk assessment is only one approach to managing risk from contamination. List two other approaches to managing risk, and describe the major difference between the three approaches. Risk-based management Adaptive management Precautionary principle Prohibition Monitoring environmental status and trends Life cycle assessment Technology-based rules Best practices, rules, or guidelines 24. Describe the most-sensitive-species and modified most-sensitive-species approaches to assessing toxicological effects on communities. Most-sensitive-species: manage contaminants at levels that protect the most sensitive species in the community; this will protect all members of the community Modified most-sensitive-species: pool summary statistics (e.g. NOECs) for the community; manage contaminants at levels that will protect a proportion (e.g. 95%) of the community 25. Draw a chart representing two communities: one with low diversity and high evenness and the other with high diversity and low evenness. Be sure to include all pertinent labels. Community 1: graph with few species, but with the same number of individuals within each Alternative: community with only a few functional groups, but with the same number of species within each group Community 2: community with many species, each with different numbers of individuals Alternative: community with many functional groups, with a wide distribution of species numbers within each group 26. A community of aquatic macroinvertebrates was monitored for structural and functional changes during repeated applications of a pesticide over a three-month period. After one or two applications, very little change in community structure or function was noted. After three applications both structural and functional measures indicated major negative impacts, however, within several weeks, the community structure and function measures had returned to pre-application levels. It was found that the latter pattern was repeated throughout the remainder of the three-month experiment. Describe the results of this experiment using the terms Elasticity, Inertia, and Resilience. No change after the first two applications indicates high inertia within the community; return to pre-application levels after the third application is an example of elasticity within the community; resilience was indicated by the ability of the community to return to preapplication structure after repeated applications. 3

4 Short Essay. Answer question 27 (15 points) and one of questions 28 or 29 (10 points each). 27. Bioethanol production presents ecotoxicological challenges at scales ranging from ecosystem to landscape, and perhaps, global. In your opinion, based on material covered in your project, as well as in class, what is the most significant ecotoxicological threat posed by increased bioethanol production? As a risk manager, what ecotoxicological data would you require in order to make decisions about whether a new bioethanol project, including increasing agricultural production to provide plant source material and a new manufacturing plant, should be approved? Make sure to justify all of your answers, and use specific examples from your own project where appropriate. Note - you can also use examples from any other projects to help make your case. Ecotoxicological data required: (Note - answers will vary somewhat, depending on individual responses to the first part of the question) - toxicity data on any additional pesticide, fertilizer, or other contaminant to be added to the ecosystem - exposure and effects data at the community and ecosystem levels for any contaminants released in the areas impacted by the increased agricultural activity as well as directly by the processing plant itself and by in distribution network for the product - data on expected long-term impacts from agricultural practices (e.g. erosion, siltation) and commercial (e.g. road-building/maintenance) activities associated with biofuel production - estimates of the impact of loss of current non-agricultural land on populations/communities/ecosystems - figures for the net CO production (from all sources) v. use of fossil fuels 2 4

5 28. Using a diagram, describe the framework for conducting an Ecological Risk Assessment. Briefly explain the function of each portion of the ERA, including points at which data is collected, and what sort of data is collected. Finally, describe when and where in the process the risk assessor communicates with the risk manager. Problem formulation - identification of ecosystem at risk, stressor characteristics, ecological effects, endpoints; discussions with risk manager set boundaries and goals Exposure characterization - how is exposure likely to occur; variations of exposure due to receptor characteristics; stressor characteristics; strength of evidence Effects characterization - ecological effects anticipated at various levels of organization; links with assessment endpoints; stressor-response profile; strength of evidence Risk characterization - integration of exposure and effects data; determine risk; quantify and communicate uncertainty Risk assessors and risk managers communicate formally at the problem formulation stage and at the risk characterization stage; risk managers and risk assessors may communicate throughout the process 29.Chemicals such as PCBs, PBBs, and perfluorooctane sulfonates (PFOS), which have been widely used in industrial and consumer products in developed countries, have been found in significant quantities in top predators in Arctic regions. A) Describe in detail all of the processes by which these industrial and commercial chemicals end up in high concentrations in animals thousands of miles from their point of origin and use. Movement and distillation of POPs (persistent organic pollutants): POPs volatilize at their point of origin, usually in temperate or tropical regions; atmospheric dynamics and prevailing winds generally carry POPs upward and north; at a temperature determined by each POPs structure, the molecules condense, usually nucleating on a dust particle, which then descends to earth; high temperatures, winds, etc. at the surface can re-volatilize the POPs, re-initiating the cycle of movement; repeated volatilization-movement-condensation cycles (e.g. in response to seasonal temperature changes) result in movement from tropical/temperate regions to poles. Once in polar regions, POPs, which are poorly degraded, typically bioaccumulate at low trophic levels and are biomagnified at higher trophic levels, such as marine mammals. B) What specific characteristics of the chemicals determine whether they will be found in temperate regions or in the polar regions? Since volatilization is required for airborne transport, any physical factor preventing or restricting the evaporation of the POP would prevent its spread. Factors restricting distribution include: low vapor pressure; high k /k, high degradation rate oc ow 5

6 Please identify at least one concept, idea, field of study, etc. that we talked about but still confuses you, or which you think should have received more attention in this class. Also, is there anything that you didn t hear about that you wanted to? (1) What is the most important thing you learned in this class? (1) 6