Section 1: fill in the blanks (2 pts each) Note: Some questions have more than correct answer.

Transcription

1 Your name: KEY Exam 2, Ornithology, EEB 484/585 Section 1: fill in the blanks (2 pts each) Note: Some questions have more than correct answer. 1. are nests structures that physically protect, insulate, and hide eggs and young birds, whereas bowers function only to. attract a female or mate One difference between bowers and leks is leks do not usually involve the creation of physical structures, leks involve more than 1 male that display together. 2. Optimal foraging theory has proven a useful tool in studying the choices birds make about what they eat. Basic OFT assumes that birds forage in such a way that they maximize their net. energy intake 3. Natural geographic variation in stable isotopes (deuterium, C13 ) over the earth s surface means that biologists can sample feathers from a bird (captured anywhere) and determine where that feather was grown. any parental care behavior: e.g., feeding rate, nest defense, ability to defend lots of resources, predator-freed territory, attentive to nest incubation 4. is an example of one direct phenotypic benefit to females for being choosy regarding the males with whom they mate with. 5. Different materials are often used in different parts of nest building. The 4 physical elements of a nest are structure, attachment, and sometimes adornment and lining. One important factor that affects what materials used in this last component of nest building is. susceptibility to water-logging, insulation needs, softness of structural materials, susceptibility to nest ectoparasites 6. List one way that the foraging ecology of a bird has affected one of that bird s sensory organs (list both foraging niche, and element of sensory organ that functions in obtaining that food): e.g., nocturnal predator/3-d sound localization, probing for buried. prey/herbst corpuscles in bill, aerial insectivore/regions of visual acuity 1

2 7. All birds have tetra-chromatic vision but species differ in the wavelengths their 4 th cone type is sensitive to. Only 4 lineages including parrots and most passerines have the ability to see. UV (ultra-violet) light Section 2: True/False (2 pts each) 8. The mafia hypothesis is one explanation for why hosts of Brown-headed Cowbirds often fail to eject parasitic eggs, even though cowbird eggs are usually very different in size and color than the host egg. The basis of this hypothesis relies on Cowbirds revisiting nests and vandalizing the nests of hosts that eject their parasitic egg. TRUE FALSE 9. Whereas it is clearly beneficial for males to engage in EPC (extra-pair copulations), there is no reason for a female to solicit EPC s because she has close to 100% certainty of maternity. 10. The hearing capabilities of most birds far exceed those of humans. TRUE FALSE 11. The partial molt that some birds undergo prior to breeding season is called the prealternate molt. 12. In MacArthur s study of warbler foraging niches, the fact that different species foraged in different parts of the tree was attributed to disruptive selection driven by competition. 13. The pecten is a sensory structure in the tips of bills of Kiwis and some shorebirds that help them detect prey in the sand or earth. Section 3: matching 14. Match the following life history traits with what you would expect of two different species of similar size nesting in the following two nest substrates (place appropriate number/letter in table cell). (6 pts) 1. Egg coloration 1A: mottled 1B: white 2. Incubation duration 2A: 20 days open cup shrub nesting species 1A 2B secondary cavitynesting species 1B 2A 2

3 2B: 11 days 3. Vocalizations 3A: sings frequently from nest site 3B: sings > 20 m from nest 3B 3A 15. Place the letter in the space on the right associated with the breeding systems that best matches the attribute. (4 pts) a) monogamy b) polygyny (maledominance defense) c) polygyny (harem defense) c d b a d) polyandry relies upon females aggregating for reasons unrelated to male quality cooperative breeding does not arise in this system in most extreme cases, results in lekking behavior and the most exaggerated cases of sexual dimorphism known in birds definition made more complex with the discovery of widespread EPC s Section 4: graphics/multiple choice (2 pts each) Circle the answer that best answers the questions related to the associated figures. 16. If you found evidence for a relationship similar to this in a species of bird you were studying, would you demonstrate that: a) this particular type of parental effort represented parental investment b) the best interests of parent and offspring differ in this species c) offspring survival increases with increasing parental care d) all of the above 17. Berthold conducted selection experiments with captive Blackcaps in Europe. The figure here represents his results that show: a) migratory behavior is learned in the species from the parental generation b) common garden experiments are not an effective means of studying the basis of migratory behavior c) migration, as measured by zügenruhe, has a strong heritable genetic basis d) all of the above 3

4 18. This sonogram depicts a vocalization of a Wood Thrush. In your text, this image illustrates the fact that: a) that the 2 sides of the syrinx can produce sounds independently b) that high frequency sound travels better in open country than in forest c) that calls have multiple functions d) none of the above The x-axes on sonograms such as this represent: a) amplitude b) pitch c) modulation d) time Section 5: scientific reasoning (10 pts each) Carefully read the scenarios below and answer the questions in a few complete sentences. 19. You are designing an experiment to determine how an unstudied species of bird navigates from its breeding area to its non-breeding area. It is known that in a closelyrelated species, young birds make this migration on their own without ever having interacted with their parents. Furthermore, preventing birds from smelling has no effect on the ability to navigate efficiently. You would like to distinguish between the following three hypotheses: i) the birds use a magnetic grid map sense to figure out where they are relative to their destination, and also magnetic compass system to guide them there. ii) the birds use a magnetic compass to guide them through a series of instructions regarding the direction & distance they must follow. iii) the birds use a celestial compass (patterns of polarized light +/or stars) to guide them through a series of instructions regarding the direction & distance they must follow. a) You perform a clock-shift experiment you alter the bird s circadian and circannual rhythms by placing them on constant 8 hour light/dark cycles in the lab for several weeks before migration. The first night following release, the birds do not navigate correctly (whereas control birds kept on ambient daylength cycles do navigate correctly). Explain & justify what you can conclude regarding your 3 hypotheses from the results of this experiment? (5 pts) You cannot distinguish between these hypotheses on the basis of this experiment. Both magnetic and celestial compass systems must be calibrated to the appropriate latitude and time of day/night circadian and circannual rhythms provide a means of calibration for both systems. b) In a second experiment, you keep the birds under normal daylength conditions, but you attach a free-floating magnet to the birds heads which creates random patterns of 4

5 magnetic fields. In this experiment, all birds navigate properly. Explain & justify what you can conclude regarding your 3 hypotheses from the results of this experiment? (5 pts) This experiment demonstrates that the birds in your experiment are not using a magnetic compass system in their navigation. If they were, then disrupting the magnetic fields should have thrown them off course. Congratulations! you have eliminated 2 of your hypotheses. You must make sure there are no alternative hypotheses consistent with the data you have so far before concluding that option iii) truly describes the navigational processes in this species. 20. You read a paper in which the authors examine the relationship between seed-caching behavior and an index of intelligence (associated with brain size) by correlating these two traits in species of landbirds. The results show that these two traits are highly and positively correlated. The authors conclude that living in cold places where seed caching is highly advantageous has selected for smart birds with good spatial memories. Evaluate the following elements of this study: a) Does this study demonstrate that differences in foraging behavior have caused the difference in intelligence? Why or why not? (4 pts) No, we cannot conclude that differences in foraging behavior have caused the differences in intelligence. Comparative studies such as this are inherently correlational, and only by conducting manipulative experiments can we infer cause and effect relationships. b) You note that most of the seed-caching birds in their database belong to just 2 families of birds. What kind of analysis should the authors conduct to demonstrate that there has been correlated evolution of foraging behavior and intelligence? (2 pts) By conducting an analysis of phylogenetically-independent contrasts, the authors could have controlled for the possibility that the correlation between seed-caching and high intelligence is an artifact of both those traits evolving by chance for different reasons in a couple of lineages, and then being conserved in all subsequent speciation events in that family. c) If (even after doing ii) there appears to be a strong correlation between foraging behavior and intelligence, offer an alternative cause-effect scenario consistent with these results. (4 pts) It is possible that high levels of intelligence evolved due to a set of selective pressures unrelated to foraging. Once the high levels of intelligence evolved, birds possessing those superior capabilities for remembering where they put things were able to begin successfully caching and retrieving seeds. Section 6: essay (30 pts) 5

6 21. Choose ONE of the following questions (a or b) upon which to write a short essay. Be sure to answer ALL PARTS of the question. Please pay attention to the structure individual paragraphs and your essay as a whole. a) A non-biologist friend invites you over to watch a video on birds in which a Superb Lyrebird imitates a huge range of sounds present in its environment. Your friend asks why it is that some birds sing such complex songs and others sing such simple ones. Answer this question by explaining the typical process of song learning and identifying how inputs during that process could affect song repertoire size (proximate explanation) and then offer an hypothesis for why selection on vocal repertoire size might vary among species (ultimate explanation). trying (2 pts) English, essay structure (6 pts) Proximate (12 pts): o Typical song learning: 1) critical learning, 2) silent, 3) subsong, 4) song crystallization (6 pts) o Variation in # of songs heard during critical learning period (how many individuals it hears singing, how big the repertoires of neighbors), could influence final repertoire size (6 pts) Ultimate (8 pts), anything coherent based on one of these 3: o relative reproductive pay-offs of having a large repertoire o relative benefits of sharing songs with your neighbors o trade-offs associated with increased learning and neural development necessary to have bigger repertoire. b). Both migration and nest-building involve a coordinated suite of complex behaviors. Thus, you could argue that both behaviors might be expected to be phylogenetically conserved (e.g., within orders or families). Explain whether or not this is true in birds and back up your assertions with evidence. Hypothesize why we might see the phylogenetic patterns that we do for both migration and nest-building. trying (2 pts) English, essay structure (6 pts) True for nest building, false for migration (4 pts) Good examples for nest building conservatism: vireos always build hanging cup in fork of tree, woodpeckers nest in tree cavities (3 pts) Good examples for migration lability: variation among species of Catharus thrushes, variation even a species-level in Black-caps, White-ruffed manakins, Dark-eyed Juncos (3 pts) 6

7 Good hypotheses for conserved nest-building (6 pts) [can be at either prox or ultimate levels]: o little genetic variation for use of novel substrates o constrained by other life-history-related traits o constrained by morphology Good hypotheses for labile migration (6 pts): o patterns of climate and resource abundance change rapidly so cost/benefit tradeoffs change rapidly relative to speciation events o migratory genetic programs can be turned on/off, don t have to re-evolve them de-novo each time 7