Mutation Definetwo of the three forces of evolution listed above, and provide a biological example. You are studying a population of field mice that includes individuals with light and dark brown coats. Every six months you perform capture/recapture experiments to census the proportion of light and dark individuals. The following numbers indicate the percentage of dark-coat individuals caught in each successive census over the course of five years:
96, 94, 95, 91, 93, 95, 74, 73, 77, 76 Explain which of the three processes of evolution is most consistent with this data, and give a hypothetical explanation for the observed changes in phenotype frequencies in this mouse population.
RUBRIC: MAX 4 POINTS Definition & Examples (2 Points Max)
(+ ½ ) Natural Selection is process by which certain alleles increase in frequency in a population because of the survival or reproduction benefit they give to those individuals who possess them.
(+ ½ ) Possible examples include sickle cell allele persists in populations where malaria is present. Other relevant biological examples are acceptable.
(+ ½ ) Genetic drift is the random change in allele frequency in a population over time.
(+ ½ ) Possible examples include brief discussion of either founder effect or bottleneck effect.
(+ ½ ) Mutation is a change in a DNA sequence.
(+ ½ ) Mentioning that mutation can create new alleles.
(+ ½ ) Mentioning that evolution by mutation can occur even if the new alleles are not acted on by natural selection.
(+ ½ ) Possible examples include: eye color gene mutates to a different color without any change in vision or behavior. Other relevant biological examples are acceptable.
Explanation of Data (2 Points Max)
(+ 1 ) Mentioning changes could not be the gradual process of natural selection because they occurred rapidly between the two censuses.
(+ 1 ) Indicating that the changes could be caused by genetic drift.
(+ 1 ) Indicating that the changes could be caused by some environmental event (flood, fire, etc.) that randomly killed many dark-coated mice.
SHORT ESSAY #2
Homeostasis, or the maintenance of a steady-state environment, is a characteristic of all living organisms. For two of the following physiological parameters, describe how homeostasis is maintained.