BI111 Chapter Notes - Chapter 65: Dominance (Genetics), Founder Group, Achromatopsia
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Evolution: change in allele frequencies in a population over time. Allele: variant form of a gene, and combinations of alleles for a trait ultimately influence an individual"s phenotype. Hardy-weinberg principle: describes a hypothetical population that is not evolving allele frequencies remain unchanged over time. Types of selection: stabilizing selection: natural selections selexts against extreme phenotypes, favoring individuals within a median phenotype. Specialize in eating the seeds of sedges. Human-caused global climate change has created a situation where many species that were adapted to previous climatic conditions are now at risk of extinction unless they are able to respond to natural selection and adapt. Sexual selection: maintains and even favors seemingly maladaptive traits if the individual with more elaborate traits are also more attractive to females and thus achieve higher fitness: ex. Elaborate antlers of many types of deer, showy feathers of male peacocks. Unlike natural selection, it doesn"t lead to adaptation and is unlikely to increase fitness.