Study Questions - Seelction in Nature
Relevant Readings: chapter 8
1) Describe how the drought of 1977 in the Galapagos affected bill size in medium ground finches on Daphne Major. Be sure to include every causal link.
2) How does antagonistic pleiotrophy affect response to selection? Use finch beaks as an example, appreciating that genes for bill width probably also made a bill 'deeper'.
3) How can the presence of a competitor act as a selective pressure? What type of change is usually seen? What pattern occurs among competing species in sympatry and allopatry? Use a real example discussed in class.
4) What effect to predators have as a selective pressure? How can the environment (abiotic AND biotic) affect these effects? Use real examples.
5) Directional selection reduces variation at a locus, and also reduces variation at linked loci through 'selective sweeps'. What effect has this had on domesticated organisms subject to rapid selection by humans?
6) How have our domesticated species caused adaptive change in humans?
7) What is a 'selective sweep' and what effect does the speed/intensity of selection have, and why?
8) What effect have humans had as selective pressures on prey species? How might this affect other aspects of their ecology (use the cod example).
9) Not all characteristics are adaptations - explain the constraints on responses to selection that falsify the notion that this is 'the best of all possible worlds'.
10) Variation at the molecular level is certainly NOT all adaptive - what predictions does the neutral model make about this variation that are supported?
11) What prediction does the neutral model make about susbstitution in proteins that is falsified?
12) How does the 'nearly neutral' model solve this dilemma?
13) In what way can 'synonymous' mutations in introns or exons change gene expression and therefor NOT be entirely neutral?