Biology 102Lecture 7Outline of Last Lecture:I. How do Species arise?II. Concepts and theories on speciesOutline of Current Lecture:I. Reproductive BarriersReproductive BarriersReproductive barrier are what keep species separate. They minimize the gene pool and prevent what species mate with whom.- Different kinds of reproductive barriers: Prezygotic barriers- any kind of barrier that prevents mating and the action of theformation of the zygote. Any kind of thing that happens before the zygote can be formed.o Different kinds of prezygotic barriers: Temporal isolation- when species breed at a different time, so it’snot possible for them to interbreed (ex. two different skunks can’tbreed together because one breeds in the spring and the other in the winter.) Behavioral isolation- when without a certain behavior or act the species will not mate with one another. (Ex. the blue footed booby has a very particular and elaborate dance it does to attract the female.) Mechanical isolation-male and female genitals that don’t work together. Gametic isolation- after copulation (ejaculation) the gametes won’t fuse together to form a zygote. (Ex. red and purple sea urchins live in one environment, sperm is released into the water, but the sperm from a purple urchin doesn’t fuse with the egg of ared one because the proteins don’t match up. Habitual isolation- when they don’t mate because they live in differernt enviroments. (ex. a snake that lives in water won’t matewith a snake that lives on land because they don’t interact with each other.) Postzygotic barriers- barriers that happen after hybrid zygotes are formed.o Different kinds of postzygotic barriers:Biology 102 Hybrid inviability- the hybrids that don’t survive Hybrid sterility- the hybrid lives but it is sterile and cannot reproduce (ex. a mule) Hybrid breakdown- hybrids that mate with each other and produce offspring but the new offspring (second generation) is sterile or
View Full Document
Unlocking...