BIO-107 test 1 Questions and Answers 100% Solved

BIO-107 test 1 Questions and Answers 100% Solved Microevolution Evolutionary change below the species level; Change in allele frequencies over generations. It is called micro evolution because it focuses on evolution in population, which is the smallest scale. (individuals do not evolve.) 3 mechanisms that cause allele change Natural seletion, genetic drift( chance events that alter allele frequencies), and gene flow (the transfer of alleles between populations). Population is a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring. Gene pool We can characterize a population's genetic makeup by describing its gene pool, which consists of all copies of every type of allele at every locus in all members of the population. Fixed if only one allele exists for a particular locus in a population. What does a population geneticist mean when he/she states that the allele for dorsal fin shape is fixed in a population of great white sharks? Means there is no homozygous/heterozygous makeup for that allele makeup. There is only one allele in the population to contribute to the shark's dorsal fin shape. Differential reproduction The idea that there is variation in the number of offspring that individuals within a population produce, is known as Differential Reproduction or Differential Reproductive Success Genetic Drift Chance events can also cause allele frequencies to fluctuate unpredictably from one generation to the next, especially in smaller population. 2 kinds of genetic drift. Bottleneck effect and founder effect Explain the role of population size in genetic drift. Think of coin flip example 700 heads vs 300 tails is suspicious but 7 heads 3 tails is not. The smaller the number of coin flips the more likely that chance alone will cause deviation from a predicted result. Bottleneck effect Sudden change in environment, such as a fire or flood, may drastically reduce population size. This sever drop in pop. Size causes the bottleneck effect. By chance alone certain alleles may be overrepresented in the survivors and others may be absent altogether or underrepresented.