What is the role of variation in evolution – if heterozygosity is reduced, what happens to the potential for evolution? The phenotype (and genotype) of a population is due to a "mosaic" of random and directed processes. Some of these have to do with history; some are related to adaptation, etc. As completely as possible, discuss the role of chance and direction in evolution and in determining the phenotype of a population.

Which of the following statements is CORRECT regarding models of adaptation that invoke allele-frequency adaptive landscapes? They assume that natural selection can either increase or decrease population mean fitness as long as there is no genetic dominance at any of the loci. They assume that natural selection can only increase population mean fitness, which means that populations can get "stuck" on local peaks associated with lower fitness than the global optimum. We can assume that such landscapes have multiple peaks only when there is no epistasis for fitness among any of the loci under consideration.

A population of 2000 mice on an island includes 40% white-furred individuals, 50% brown-furred individuals, and 10% black-furred individuals. A storm hits the island and decimates the population, leaving about 100 individuals, of which 75 are brown and 25 are white. The fur color of this population remains stable at about 75% brown and 25% white over the next several generations. -‐has evolution occurred? If so, by what process(es)? -‐has natural selection occurred? Why or why not? ­‐Is the current population in Hardy-Weinberg equilibrium? yes no can't tell. Explain your answer.

Evolution determines the change in inherited traits over time to ensure survival. There are three variants identified as Variant 1 with high reproductive rate, eats fruits and seeds; Variant 2, thick fur, produces toxins; and Variant 3 with thick fur, fast and resistant to disease. These variants are found in a cool, wet, and soil environment. In time 0 years with cool and wet environment, the population is 50,000 with 10,000 Variant 1, 15,000 Variant 2, and 25,000 of Variant 3. Two thousand years past, the environment remained the same with constant average temperature and rainfall. Variant 1 with a population of 26,000, Variant 2, 35,000, and Variant 3, 62,000. A disease spread throughout the population. However the population increased to 72,000. Determine the percentage increase in the population of the variants.