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Eco Evo Exam 2 (c.7)
Definitions
Term | Definition |
---|---|
Deoxyribonucleic acid (DNA) | A molecule composed of two strands of nucleotides that are wound together into a shape known as a double helix. |
Chromosomes | Compact structures consisting of long strands of DNA that are wound around proteins. |
Alleles | Different forms of a particular gene. |
Polygenic | When a single trait is affected by several genes. |
Pleiotropy | When a single gene affects multiple traits. |
Epistasis | When the expression of one gene is controlled by another gene. |
Heterozygous | When an individual has two different alleles of a particular gene. |
Homozygous | When an individual has two identical alleles of a particular gene. |
Codominant | When two alleles both contribute to the phenotype. |
Dominant | An allele that masks the expression of the other allele. |
Recessive | An allele whose expression is masked by the presence of another allele. |
Gene pool | The collection of alleles from all individuals in a population. |
Mutation | A random change in the sequence of nucleotides in regions of DNA that either comprise a gene or control the expression of a gene. |
Random assortment | The process of making haploid gametes in which the combination of alleles that are placed into a given gamete could be any combination of those possessed by the diploid parent. |
Mutation | A random change in the sequence of nucleotides in regions of DNA that either comprise a gene or control the expression of a gene. |
Recombination | The reshuffling of genes that can occur as DNA is copied during meiosis and chromosomes exchange genetic material. |
Genetic drift | A process that occurs when genetic variation is lost because of random variation in mating, mortality, fecundity, and inheritance. |
Bottleneck effect | A reduction of genetic diversity in a population due to a large reduction in population size. |
Founder effect | When a small number of individuals leave a large population to colonize a new area and bring with them only a small amount of genetic variation. |
Selection | The process by which certain phenotypes are favored to survive and reproduce over other phenotypes. |
Stabilizing selection | When individuals with intermediate phenotypes have higher survival and reproductive success that those with extreme phenotypes. |
Directional selection | When individuals with an extreme phenotype experience higher fitness than the average phenotype of the population. |
Disruptive selection | When individuals with either extreme phenotype experience higher fitness than individuals with an intermediate phenotype. |
Microevolution | The evolution of population. |
Artificial selection | Selection in which humans decide which individuals will breed and the breeding is done with a preconceived goal for the traits of the population. |
Industrial melanism | A phenomenon in which industrial activities cause habitats to become darker due to pollution and, as a result, individuals possessing darker phenotypes are favored by selection. |
Macroevolution | Evolution at higher levels of organization including species, genera, families, orders, and phyla. |
Speciation | The evolution of new species. |
Phylogenetic trees | Hypothesized patterns of relatedness among different groups such as populations, species, or genera. |
Allopatric speciation | The evolution of new species through the process of geographic isolation. |
Sympatric speciation | The evolution of new species without geographic isolation. |
Polyploid | A species that contains three or more sets of chromosomes. |