Evidence of EvolutionEvolution is supported by embryology, structures, and genealogy. Embryology is the embryos. Charles Darwin noticed the resemblances of different embryos, which revealed a “community of descent”. More evidence supporting evolution can be found in evolutionary structures. Homologous and analogous structures show how the ancestors evolved to be different and to be the same, respectively. FInally, genealogy, the study of Mr. Jeans, shows the variation of genes over time by evolution.
Principles of EvolutionOverproduction, variation, competition, and adaptation drive evolution. If a species over- produces offspring, only the strongest and most evolved survive. Variation in genes also leads to some offspring being stronger than others. Also, competition over food causes only the most adapted to have more food and survive. Finally, adaptation causes some offspring to have traits more suitable for the environment, which leads to evolution.
Phenotype FrequencyPhenotype frequency, or the number of individuals in a population with one specific trait, is theorized to help evolution because the more of one trait there is, the better opportunity for it to survive. Three types of natural selection (evolution) that occur with phenotypes are directional, stabilizing, and disruptive. Directional selection is when the phenotypes change due to environmental change. Stabilizing selection is when the phenotypes eventually reach an average level and stabilize. Disruptive selection is the opposite of stabilizing, and is when the phenotypes become different to the extreme.
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Environmental ChangesChanges in the environment often lead to adaptation in population. For example, the after the peppered moths’ environment became industrialized, the population changed color to match it. Another example of this type of adaptation is when the finches on the Galapagos Islands evolved to have different beak sizes to accommodate their environment and food source.
Geographic and Reproductive IsolationGeographic isolation, or when a population is separated from others of the same species (eg. a mountain range vs. plains), leads to divergence because natural selection will select against different traits for different environments. Reproductive isolation is when different species live in the same area but cannot breed because of their varying properties. Ovulation times are menstrual cycles and seasonal changes can cause more diversity.
Human Impact on BiodiversityHumans have impacted the biodiversity of the environment in many ways. These include, but are not limited to: over-consumption, increased population growth, increased economic growth, and more industrial activity. All of these have been harmful to the environment, and will continue to harm the biodiversity if changes aren’t made. Some possible solutions to reduce human impact are to convert to sustainable energy sources, such as solar and wind, reuse wasted materials, not overproduce goods, use contraception methods to reduce unwanted birth rates, use electric vehicles instead of gas, and actively engage in helping species that are endangered.
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