Biology 102Lecture 5Outline of Last Lecture:I. Gene FlowII. Natural SelectionOutline of Current Lecture:I. Sexual SelectionII. DarwinIII. AnatomySexual SelectionSexual Selection- produces sexual dimorphism- Sexual dimorphism- males and females who have different traits. The traits that distinguish them.- 2 ways it can work:1. Females are choosy, meaning they are looking for some kind of trait and the male must possess that specific trait. Basically the guy is trying to impress thegirl2. Male competition- females do not have a choice. There is usually some kind of “battle” of some kind and the victor gets to mate with the female, she has no say in the matter. Basically the strong guy gets whichever girl he wants.Darwin- Believed in biogeography- Suggests that animals that look similar have common ancestors but each one adapted differently to the environment- Compared Galapagos animals to animals in Australia, they were similar except the ones in Australia were marsupialAnatomy- Comparative anatomy- comparison of the bodies of different species- Homology- the result of comparative anatomy - Similarity in traits that are a result of common ancestry- Different function but similar structure (ex. hands)- Analogy- similar function but different structure (ex. dragonfly wings compared to bat wingsBiology 102Populations exhibit geographic variation: meaning a bison that lives in one area is going to live different in another area- Different traits for a different environmentMolecular Biology- when the DNA is compared of different organisms to see the likeness in one
View Full Document
Unlocking...