Wild turkeys are dramatically sexually dimorphic | Homework Help
- These are five essay questions for evolutionary biology
- Wild turkeys are dramatically sexually dimorphic; domestic turkeys are far less so. Suppose that female wild turkeys chose males on the basis of expensive traits that indicate disease resistance and that artificial selection for rapid weight gain in domestic turkeys destroys female choice. What would you predict about the evolution of disease resistance in domestic turkeys? If we observe that domestic turkeys are less resistant, does that necessarily mean that wild females had been choosing more-resistant males, or are other hypotheses equally plausible? Please include at least one scientific research article to support your response.
- The main processes involved in speciation are genetic separation and phenotypic differentiation. Provide a discussion of at least two (2) plausible causes for both.
- Deviations from the environment to which we are adapted have been used to explain a large variety of conditions, including suIDen infant death syndrome (SIDS), the persistent crying known as colic, lower back pain, drug aIDiction, and depression. Consult the scientific literature for details on one such condition and then evaluate the quality of evidence for an evolutionary interpretation of the condition. Be sure to provide references.
- Sand gobies are a small, shallow-water marine fish in which males construct nests underneath empty mussel shells. Females come and lay eggs in the mussel shell nest, and males then guard the eggs until they hatch. Males fan water over the eggs with their fins while the eggs develop. The more eggs in their nest, and the more those eggs consume oxygen from the surrounding water, the more the male will fan the eggs.
Kai Lindstrom and colleagues were curious about how females choose males. In a first experiment, females were placed in an aquarium from which they could view two males, one of whom had been provided with a small nest (a 6cm wide flowerpot nested within a 10cm wide flowerpot), and the other with a large nest (a 10cm flowerpot). Females were kept (with clear partitions) to the side of the nest so that they could not see the inside of the nest – from their point of view, the nests appeared identical. They could, however, see the male at the nest entrance. In a second experiment, low-oxygen water was piped into one of the nests. Again, the females could not perceive the difference in oxygen level from their location-all they could view from their vantage point was the male at the entrance of the nest.
Two experiments were conducted. After the females had been given ample time to view the males, the small flowerpot was removed (in the first experiment) and the low-oxygen water pipe turned off (in the second experiment). The female was then given access to the entire aquarium and allowed to inspect the inside of the nests for the first time. What she saw was that both males had identical nests-10cm wide flowerpots with normal oxygenation. Yet, in the first experiment, 82% of females first chose the male who initially had the larger nest. In the second experiment, 73% of females first chose the male who initially had low-oxygen water piped into his nest earlier.
What explanation do you have for these results? How were females able to perceive differences in nests that they could not see, and why did they make the choices that they did?
- Why do pathogens evolve quickly?