Unit 8 Reflection

In this unit we learned about what evolution . Variation exists everywhere and is only a difference in traits within a population. The gene pool is the total of all alleles in a population for a trait. Gene pools change as new allele combinations form when individuals of the population have offspring. The winners pass on their alleles to their offspring. A species is a group of individuals that can reproduce and have fertile offspring. Behavioral isolation is caused by changed in courtship or mating. behaviors or occupying different niches. Embryology is where similar stages of embryo development suggests common ancestry. Hox genes are responsible for turning on other genes during development. Index fossils are species that are understood well and used for comparison. Homologous structures have the same structures but have different functions which shows common ancestry. Analogous structures have the same function but different structures. It's not individuals that evolve, but the species that do. Natural selection can change the distribution of a trait in three ways, directional selection, stabilizing selection, and disruptive selection. Directional selection favor phenotypes at one extreme. Stabilizing selection favors both extreme phenotypes. Disruptive selection favors both extreme phenotypes. Genetic drift is when a random event drastically changes a population and results in change in allele frequency. Adaptive Radiation is when there is rapid speciation from a common ancestor. As demonstrated in the Hunger Games Lab, we simulated a real world population and we saw how the different species "evolved".





Homologous structures:
       



Analogous structures: