BIOL 100 Lecture Notes - Lecture 17: Volcanism, Extinction, Background Extinction Rate
Document Summary
Describe comparative genetics as it pertains to evolution. Discuss allopatric and sympatric speciation; dispersal and vicariance. Similarities between species often are best observed in embryos. Homeotic genes- regulate development, small differences- > large effects. Similarities in dna and protein sequences say ancestor- descendent relationship. More difference in gene expression= greater distance two species have from common ancestor. Microevolution- evolution in a single population (small scale) Population localized group of individuals who can reproduce and have fertile offspring (species) Gene pool all the alleles for all loci in population. Locus- fixed location on the chromosomes, it is fixed if all individuals in population have same form of allele. Macroevolution- evolution above species level (large scale), caused by speciation. Two general modes: allopatric speciation and sympatric speciation. 99% all species that have lived are no extinct. Species are group of interbreeding individuals of common descent that are reproductively isolated from other groups.
