Concept Quiz 1. In which of the following pairs do both evolutionary processes introduce new genetic variation into a population? Mutation and gene flow. 2. One of the original Amish colonies rose from a ship of colonists that came from Europe. The ship's captain, who had polydactyly, a rare dominant trait, was one of the original colonists. Today, we see a much higher frequency of polydactyly in the Amish population. This is an example of genetic drift and founder effect. 3. Gal á pagos medium ground finches are found on Santa Cruz and San Crist ó bal islands, which are separated by about 100 km of ocean. Occasionally, individuals from either island fly to the other island to stay. This can alter the allele frequencies of the population through which of the following mechanisms? Gene flow. 4.All of the alleles carried by all of the individuals in the population are called? Gene pool. 5. Unless evolutionary forces are acting on a population the allele frequency of the gene pool will stay the same. Evidence of Evolution Evidence of evolution include; o Fossils, species similarities, and observable adaptation. Fossilized archaeopteryx: feathers & teeth, links dinosaurs and birds. Humans share 98% DNA with chimpanzees. Humans share 85% DNA with mice. Genes contain overwhelming evidence for evolution. Physical Evolution Homologous Structures: (equivalent structures) Evolution would predict that different species with common ancestors would have structures that share common elements regardless of present day function. Homology: Compare limbs of mammals o They all have the same bones but with different proportions to suit different functions. o Grasping, running, swimming, flying Analogous structures: wings of an eagle and wings of a dragonfly
o Look similar between species. o Have the same function o Have different structures and development o Suggests they do not share a recent common ancestor. Evidence o Vestigial Structures: Some structures and organs may become less important for survival until they are no longer of use. o Humans: ancestral tail. o Vestigial organs Adaptations: Why do you get goose bumps? o Ability for mammals to raise their hairs of their limbs and body probably was initially for warmth in cold weather. o Later used to make an individual look bigger when faced with a dangerous predator. Evidence: Transitional fossils o Many fossils show clear transition from one species, or group, to another. Evidence: Bio geology o Geographic spread of organisms also tells of their past evolution. Parallel evolution: (convergent evolution) each of these species pairs is not closely related, but have similar adaptations in different parts of the world.
- Spring '15