Evidence For Evolution Jesus Trochez, David Rodriguez, Rodolfo Hernandez, Dionisio Diaz, Luis Anaya

Peppered Moths and Industrial Melanism When the environment changes natural selection may favor different traits in species. Extensive genetic analysis has shown that the moth’s body color is a genetic trait that reflects different alleles of a single gene. Light colored moths became extinct because they were visible to everyone. Industrial Meleanism- Refers to the phenomenon in which darker individuals come to predominant over lighter ones.

Evidence of natural selection Natural selection requires three condition: 1. Variation must exist in the population. 2. This variation must lead to differences among individuals in lifetime reproductive success. 3. Variation among individuals must be genetically transmissible to the next generation. When Darwin visited the Galapagos Islands he collected 31 specimens of finches from the three islands. Darwin’s observations suggest that differences among species in beak size, and shape have evolved as the species have adapted to use different food resources.

Fossil Evidence When fossils are arrayed according to their age from the oldest to youngest, they provide evidence of evolutionary change. By dating the rocks which where the fossils were we can estimate the age of the fossils found.

Artificial Selection Change in the genetic structure of populations due to selective breeding by humans. Many domestic animal breeds and crop varieties have been produced through artificial selection.

Anatomical Evidence Some of the strongest anatomical evidence supporting evolution comes from comparisons of how organisms develop. Embryos of different types of vertebrates for example often are similar early on but become more different as they develop. Early in their development vertebrate embryos posses Pharyngeal pouches which develops into a different structure. In humans for example they become various glands and ducts, and fish turn into gill slits, at a later stage every human embryo has a long tail, the vestige of which we carry to adulthood as the coccyx at the end of our spine. Human fetus’ even posses a fine fur (lanugo) during the fifth month of development.

Convergent Evolution In the best know case of convergent evolution two major groups of mammals- Marsupials and placentals- have evolved in very similar ways in different parts of the world. Marsupials are a group in which the young are born in a vey immature condition and are held in a pouch until they are ready to merge into the outside world. In Placentals by contrast offspring are not born until they can simply survive in the external environment.