Biology II: Ecology & Evolution Exam - Population, Productivity & Predation - Prof. Marjor, Exams of Biology

Download Biology II: Ecology & Evolution Exam - Population, Productivity & Predation - Prof. Marjor and more Exams Biology in PDF only on Docsity! BSCI 106 – PRINCIPLES OF BIOLOGY II: ECOLOGY AND EVOLUTION LECTURE EXAMINATION I July 24, 2009 Your Name__________KEY__________________________ Your TA’s Name________________________________ Section Time/Number________________________________ Exam Policies:  Make sure that you read the entire question and all parts of a question.  Answer all questions and parts of a question.  You must answer the “Short Answer” Questions within the space provided. Answers outside of this area will not be graded. If you are writing your answers in pen, you can use the backs of the pages to organize your thoughts and answers first, then write your answer in the space provided.  No cell phones, graphing or programmable calculators or other electronic devices (turn off and place inside your book bag).  Put book bags completely under your seat.  Alternate seats (and in longitudinal columns).  Regrades only for exams written in pen.  Open exam only when told to begin.  Do not leave during last 10 minutes (after 12:10 pm).  Stop immediately when told exam is over.  After 12:10 pm, stay in your seat until all exams are collected.  WRITE NAME ON EACH PAGE. 1 Name_______________________________________ MULTIPLE CHOICE (5 points each): NOTE THAT, IN EACH QUESTION, EITHER NONE OR ALL OF THE ANSWERS MAY BE CORRECT. 1. “Population characteristics” that we use to describe and predict how population numbers change over time include: a. presence of horns or antlers. (b.) the total number of births per unit time. (c.) the per capita number of deaths per unit time. d. metabolic rate. (e.) age-specific fecundity. 2. Exponential growth of the population: (a.) is influenced by the size of the population, N. b. results from the operation of density-dependent factors. (c.) often is observed when the population colonizes a new unoccupied environment. d. often is associated with competition for resources. e. is more likely to occur in K-selected than in r-selected populations. 3. Competition a. always occurs between individuals of a species. b. is always associated with the evolution of fighting mechanisms (c.) often is asymmetric (affects one species more than the other) when it occurs between species. (d.) may include differential efficiency of extracting a limiting resource but no physical contact between species. (e.) may depress the growth rate of a population. 2 More predators in the tropics may result in more species there because they prevent competitive exclusion in the lower trophic levels. More direct sunlight (= more energy, more primary productivity) in the tropics. Less effect of earth tilt (=less seasonality, less disruption of populations by extreme heat or cold) in the tropics. There are others that we didn’t discuss with specific relation to latitude which would be correct if provided ---- such as more competition in the tropics = more niche divergence/species packing, tropics are older and/or more stable over evolutionary time (probably not true but is in the literature), more speciation/origination or less extinction in the tropics (latter not true but has been hypothesized in the literature), etc. Count these correct if they are in the literature and are properly explained. Name_______________________________________ 17. Draw a graph and label three types of survivorship curves on it (be sure to label the axes on your graph).Survivorship curves (Fig. 52.2) 18. (a) Where, on the following density-limited graph for ocean fishes, could one harvest the maximum number of individuals without reducing the population size over the long term (identify [arrow] the part of the curve that would allow the maximum sustainable yield)? (b) Where is K on the following graph (label the part of the graph that corresponds to K)? (c) Label the axes of the graph. 5 19. Give an example of a mutualistic association between two species (or groups of species) that we discussed and name one benefit that each species receives. Any example discussed in class or in the text book that makes sense. Name_______________________________________ 20. Given that a “niche” is an n-dimensional description of resource use, habitat, and lifestyle of a species (all of which can be defined as its “niche space”), describe what a “fundamental niche” is, and what a “realized niche” is. Explain which is larger in your answer. Fundamental niche = all of the ways in which a species potentially can use/interact with its environment (i.e., all the ways of which it is physiologically capable of living in its environment). A = Large r, Low N C = Small r, High N N B = maximal sustainable harvest = Middle r, Middle N K 6 Time Realized niche – the actual ways in which a species uses/interacts with its environment, which is smaller than its fundamental niche due to interactions with other species (don’t have to include due to interactions with other species). 21. Give one reason for why trophic pyramids support lower amounts of biomass in their upper levels, ie, why is there more biomass among primary producers than among top carnivores? Because a large proportion of material eaten can not be digested (is lost as feces) or is lost as detritus. Because a large amount of material eaten is lost as heat due to respiration. Because of trophic inefficiency (or can discuss P2/P1) (can call this “trophic efficiency” – term presented in class) Because trophic efficiency declines at each higher trophic level. --------------------------------------------------------------------------------------------------------------------- Do not write below this line Name_______________________________________ SHORT ESSAY (15 points) 22. (a) Draw a graph that demonstrates what is often called the “intermediate disturbance hypothesis”, where you show the relationship between predation (a form of disturbance) and species diversity in a community. (b) Label the axes (showing directionality). (c) Describe why the curve has the shape it does and thus why predation/disturbance is thought to affect the diversity of biological communities (this is the critical part of this question—indicate where and how competition and predation/disturbance operate and what are their effects upon diversity of the community). (d) Give an example of a system in which this curve operates to control species diversity of a natural community in either ecological or evolutionary time (be sure to explain whether you are discussing an ecological or an evolutionary time frame). 7