EnSt/Bio 295 Exam II(fl06) This test is worth 100 points; you have approximately 50 minutes. Allocate your time accordingly.

Transcription

1 EnSt/Bio 295 Exam II(fl06) This test is worth 100 points; you have approximately 50 minutes. Allocate your time accordingly. MULTIPLE CHOICE (2 points each) _BDE_1. In kelp forest ecosystems the following species acts as a keystone A) Sea urchins B) Sea otters I accepted either of these answers here but you had to include the otter. C) Kelp D) All of the above E) A and B C 2. The following provides evidence for genetic determinism of behavior: a) Fos B knockout mice are less effective parents. b) Rats that are selected for maze navigation improve search times. c) Hatchlings of Eastern European black-caps migrate westward from Great Britain. d) All of the above. e) None of the above. Genetic determinsm = instinctive behaviors, C is the only one that s instinctive D 3. Two species of barnacle, Chthamalus stellatus and Balanus balanoides, are found on the rocky coast of Scotland. If Chthamalus, which normally occur higher in the intertidal zone, is limited in its distribution by competition with Balanus; and Balanus, which normally occur lower in the intertidal zone, is limited in its distribution only by its tolerance of dessication (drying: during low tides), then (identify all that apply): A) Chthamalus and Balanus are both found in their realized niches. B) Balanus is found in its fundamental niche. C) Balanus is found beyond its fundamental niche, whereas Chthamalus is restricted to its realized niche. D) A and B E) None of the above. A 4. The following provides an example of resource partitioning A) Two competing species of paramecium segregate along an oxygen gradient in a test tube. B) Semibalanus balanoides excludes Chthamalus stellatus from below tide habitat. C) Allopatric species of Darwin s finches feed on seeds of different sizes D) Removing rodents results in ant extinction because they specialize on plants with different seed size. E) A and C A 5. Which of the following can result in primary succession A) An intense fire B)A mature tree dies and falls C)An agricultural field is abandoned D) A beaver creates a damn in a freely flowing stream. E) All of the above. B_ 6) Which of the following is clearly not an example of learning? A) A near death experience at the hands of a bear imparts a fear of bears in a young rabbit even though the rabbit never encounters another bear B) A young sea turtle follows the moonlight to the ocean immediately after hatching C) When asked a question about material from a college class 10 years earlier, the former student cannot recall any pertinent information D) None of the above are examples of learning E) All are examples of learning B instinctive behaviors are not learned, A learning allows for never using and C - forgetting

2 C_ 7) Which of the following cases are examples of true communication A) While singing a mating song to attract females, a male cricket is overheard and eaten by a lizard. B) A bull frog blows himself up and emits shrieking calls to deter an attacking opossum. C) A male lion roars to locate separated members of the pride. D) B and C E) All of the above. Both must benefit 2) True-False (2 pts each) F_ a. In order to be classified as a disturbance, an event must impact all members of the community in some way, even if not equally. Disturbances do not need to impact all members only some. T_ b. When considering multiple interaction in nature, predation tends to reduce competition among prey species. This shows that predation can actually be less important to a species continued survival than competition. F_ c. The concept of a species niche is synonymous with a complete description of a species habitat. A niche includes more than habitat, ex. Foods, role, etc. T_ d. When modeled experimentally, predators always drive prey to extinction without refuges. F e. Parasitism is not viewed as predation because a host is never killed by its parasite. Many parasites kill their hosts, the difference lies in the time frame. F f. A major stumbling block for the Cascade theory of Killer Whale Predation is that orcas have only recently started exclusively feeding on sea otters despite the effects of industrialized whaling occurring over 20 years ago. A time lag is part of the theory, its not a problem for it. F_ g. All instinctive behaviors are genetically determined but not all instinctive behaviors have a genetic basis. All instinctive behaviors have a genetic basis. F_ h. The fact that pigeons can be taught to associate colors but not sounds with danger illustrates the concept of learning preparedness. Colors are not biologically relevant to danger, sounds are. T i. Many do not consider sensitization a true form of learning as it is indiscriminate and short-lived. F j. There is a strong correlation between the complexity of an organism s communication or the amount of information they convey and the number of signals they utilize. Think about enrichment devices. T k. All symbiotic relationships carry the potential for co-evolution. TF l. Evidence for a genetic basis of behavior can come from single gene mutation experiments that demonstrate that one gene alone can be responsible for the formation of a behavior. I deemed this confusing and accepted either answer.

3 Fill in the blank. Be as specific as possible. (2 points each) a) Auditory signals are often used both to locate others at a distance and alarm calling even though they are considered indiscriminate, whereas chemical work well around obstacles but are not fast. b) Measurements of species diversity include both species richness and evenness. c) Three fundamentally different types of prey refuges are space, size, and numbers. d) Morphological evolution toward niche divergence in the face of competition is known as character displacement and would expected to be greater in sympatric populations vs. allopatric populations. e). A grassland has low inertia as it can be disturbed easily but has high renewal and can recover well from disruption. f) When two dangerous species are both brightly colored and look alike they are called mullerian mimics, while two brightly colored species who look alike but are not both dangerous are call batesian mimics. g) A relationship in which one species benefits while the other is not harmed is commensalistic while a relationship in which neither individual can live without the other is called obligate mutualism (Be Specific). h) The two main types of associative learning are classical and operant conditioning. i) The three basic processes that drive ecological succession are tolerance, facilitation, and inhibition. Short Answer 1) Explain how sensitization may be considered both adaptive and non-adaptive. (4 points) Adaptive A positive or negative event may indicate that more are near/likely. It may pay to be extra alert. Non-adaptive It may be just an artifact of the nervous system. Being hypersensitive to everything may cause you miss something important. Also may waste energy and time.

4 2) Define a keystone species. (2 points) Keystone species have a disproportionate effect on community structure and function given their relative abundance. Thinking about keystone species as a whole, the most common type of keystone species is what? List an example of a species that does not fit this pattern. (2 points) Top level predators are typical keystone species. Beavers and fig trees are examples of keystone species that are not predators. 3) Communities with high levels of productivity usually promote high levels of species diversity. Yet, planted communities like crops or tree farms tend to have low levels of species diversity. How would you explain this? (4 points) Complexity is the key here. Despite high productivity they have little complexity, which does not lend itself to high diversity. They are also managed to have low diversity (pesticides / herbicides) 4) Describe the premise behind the Cascade Theory of Killer Whale Predation (Should only require a sentence or two). What is needed to prove this theory true? (4 points) Cascade theory says that as orcas main food source was eliminated/depleted, orcas shifted their eating habits to other marine mammals in a sequential manner with respect to size. What we need to prove the theory is evidence that orcas will shift their eating preferences back to whales as the population rebounds if given the cance. 5) Give three reasons why climax communities are not nearly as clearly defined as once was thought. (6 points) (You can basically list these but make sure the point is clear on each) Three of the following 1) Communities constantly change due to abiotic factors (climate change) and biotic factors (evolution) 2) Interpreting the climax depends on the natural processes present (ie, natural fire regime for Oak-Hickory forest). 3) Succession can be an extremely slow process 4) Some communities are constantly disturbed (Disclimax communities)

5 6) a) Explain the difference between a cardinal and an ordinal index of species diversity and give an example of a situation in which you might favor using one type of index over the other. b) Explain a weakness of using species diversity indices other than use of index or measurement issues. (6 points) Cardinal index: all species are equal Ordinal index: species are weighted by importance Ordinal indices would be appropriate for communities with keystone species. Diversity indices do not directly account for the variety of families / groups of species in a community. 7) Foresters are considering building a road through a contiguous 1000 hectare forest. Describe how this road could disproportionately affect species using this habitat. Briefly give a real life example from class of how a species can be negatively impacted by this change.. (6 points) Building a road introduces edge, which can disproportionately affect organisms adapted to the core. American migratory songbirds are affected because of habitat loss and because predation and nest parasitism increase near edges. 8) Describe two means by which intermediate levels of disturbance can maximize species richness on a landscape. (4 points) Intermediate levels of disturbance prevent competitively dominant species from excluding pioneer species maximizing local species richness with respect to time since disturbance. On a landscape patches in different successional stages allow the entire range of species to be present. 9) What is the relationship between species diversity / complexity and ecosystem stability (Be specific)? Give an argument for and against higher complexity leading to higher stability? (6 points) More diverse communities are thought to be more stable but its unknown to what degree. I.e. Does continuing to add species past some point always increase stability? In support of this idea, more diverse communities may have more functional redundancy among species, allowing one to fill in for another if it is eliminated by disturbance. However, more diverse communities may be more interconnected such that the removal of an important species, like a keystone, may have dramatic effects.