Evolution And Natural Selection Summary

Chapter ten focused primarily on evolution and natural selection. Evolution are the changes in traits, phenotypes, of groups of organisms over time. Darwin was influenced by Lamark and Malthus, who were other scientists during his time. Lamar believed that acquired characters are passed on to offspring. For example, giraffe necks would change for “adaptation”. Giraffes would be born with longer necks. Malthus believed that populations try to go beyond support capacity. He believed they go through competition and struggle for survival amongst each other. At the Galapagos Islands, Charles Darwin believed that species were similar to, but not the same as, species on the mainland of South America. He found that species varied from island to
Species had reached islands from the mainland and seemed to have different changes on different islands. The three main concepts of natural selection are that species change over time, divergent species share a common ancestor. An example of divergent species would be Darwin’s finches in the Galapagos Islands. The last concept of natural selection is the mechanism that produces the change itself is natural selection. There are four basic principles of natural selection. The first principe is that more individuals are produced from each other generation than can survive. This idea is from Malthus. The seconds principle is that phenotypic variation exists among individuals and that it can also be heritable. The third principle is that individuals with heritable traits that are better suited to the environment will survive, and favorable, adaptive, traits will accumulate in the population. The last principle is that when reproductive isolation occurs, new species will form. Fitness is a phenotype that is determined by the relative rates of survival and reproduction of individuals with that