BI111 Lecture Notes - Lecture 2: Species Problem, Gene Pool, Macroevolution
Document Summary
Speciation: process through which a new species arises, macroevolution - takes a long time to evolve into new species. Galapagos finches - came from one common ancestor, for example change in shape of their beak. In the limited gene pools of an isolated population, over many generations, genetic differences may accumulate to the point where populations are no longer able to interbreed. Gene pool: all the genes in a population, different species have different genes. **blue line represents physical barrier, in which over time the barrier makes the two populations unable to ever interbreed or make fertile offspring. Species concepts: biological species concept: group of organisms that can interbreed and form fertile offspring. Cannot be used exclusively asexual organisms (prokaryotes, amoeba, fungi) Horizontal gene transfer cannot be explained by bsc. Horizontal gene transfer : individual -> individual, not parent-offspring. Can occur between organisms of different species, kingdom or domains. E. coli has picked up shiga toxin gene from shigella.
