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| 211013443 | Industrial Melanism | In preindustrial England, most peppered moths were light colored because they were camouflaged by teh lighter countryside and had the advantage over dark moths. Industrialization changed teh environment, making it soot covered and dark. Light moths were no longer camoflauged and were preyed upon by birds. Their numbers declined, leaving dark moths with the advantage. Dark moths survived and passed on their genes. Over a short time, the population changed and most peppered moths were dark. | |
| 211013444 | Developing Antibiotic Resistance | Bacterial resistance to antibiotics is carried on plasmids that can be transferred from one bacterium to another; exposure to a particular antibiotic kills only those bacteria not carrying resistance to it; resistant bacteria then reproduce without competition, producing an entire population that is resistant to antibiotic. | |
| 211013445 | Sources of Population Variation | Tremendous variation is hidden in any gene pool and can be expressed by selective pressures. For example: there is tremendous variation among dog breeds although they all belong to the same species. | |
| 211013446 | Balanced Polymorphism | The presence of two or more phenotypically distinct forms of a trait in a single population of a species. Each Morph is better adapted for a different area. For example, the shells of one species of snail can exhibit a wide range of colors and banding especially adapte for a particular area within its range. | |
| 211013447 | North South Cline | One species of rabbit exists in two different regions in North America; rabbits in the cold, snowy northern regions are camouflaged with white fur and have short ears to conserve body heat. Rabbits living in warm, southern regions have mottled fur that blends in with woodsy areas and long ears that radiate off excess body heat. | |
| 211048530 | Mutation | Any change in genetic material. Raw material for evolutionary change. A major source of variation. Rarely Occur, but their cumulative effect at all loci in a population can be significant. Can occur in the DNA or at teh chromosome level. Chromosome mutations can be seen on a karyotype. | |
| 211048531 | Outbreeding | The Opposite of Inbreeding; The mating of organisms of the same species that are not closely related in order to maintain variation within a species and strong gene pool. In plants the male and female parts do not mature at the same time. In animals the dominant male may chase away young males so they do not inbreed. | |
| 211048532 | Diploidy | The normal condition of sexually reproducing organisms. Two copies of every gene (except the Y chromosome). This 2n condition maintains a hidden pool of alleles that could be advantageous if conditions change. | |
| 211048533 | Heterozygote Superiority | The hybrid state is selecte for because it has a greater survival rate and reproductive success. This leads to a population that reatins a great variation of alleles. | |
| 211048534 | Frequency-Dependent Selection | Also called minority advantage. Decreases in the frequency of the more common phenotypes and increases the frequncy of less common ones. IE the most common prey will be preyed upon disproportionately while the less common ones will escape predation because they may not be recognized as prey. | |
| 211048535 | Population Evolution causes | Genetic drift, gene flow, mutation, nonrandom mating, natural selection | |
| 211048536 | Genetic Drift | A change in the gene pool due to chance (examples are bottleneck and founder effects) | |
| 211048537 | Gene Flow | The movement of alleles into or out of a population. Occurs as a result of the migration of fertile individuals or gametes among populations. an example would be pollen from one valley being carried across a mountain by wind to another valley. | |
| 211048538 | Non random mating | Individuals choose mates that are best adapted. Serves to eliminate less-fit individuals or genes from a gene pool. | |
| 211048539 | Bottle neck effect | a form of genetic drift. Natural disasters reduce the size of a population unselectively and cause the loss of genetic variation resulting in a much smaller population with some alleles over or under represented. | |
| 211054144 | Founder Effect | a form of genetic drift. When a small population breaks away from a larger one to colonize a new area and the smaller group is not representative of the original population because rare alleles may be overrepresented. An example would be the Amish community founded by individuals with rare polydactyly trait making the Amish have a high incidence of polydactyly. | |
| 211054145 | Hardy-Weinberg Equilibrium | Describes a stable, nonevolving population where allelic frequncies do not change. The population must be large, isolated, with no mutations, no natural selection, and mating must be random. | |
| 211054146 | Hardy-Weinberg Equation | P+Q=1 or p^2+2pq+q^2=1 where p=dominant allele, q = recessive allele, and 2pq = the hybrid state. | |
| 211054147 | Species and Speciation | A species is a population whose members have the potential to beed in nature and produce fertile offspring. Anything that fragments a population and isolates small groups of individuals may cause speciation, the formation of new species. | |
| 211054148 | Allopatric Speciation | Caused by geographic isolation: mountains, rivers, canyons, lakes... | |
| 211054149 | Sympatric Speciation | Caused by something other than geographic Isolation such as polyploidy, habitat isolation, behavioral isolation, temporal isolation, reproductive isolation. |
