BIOL 1202 Chapter : Chapter 24 The Origin Of Species
Document Summary
Microevolution changes over time in allele frequencies in a population. Responsible for diversity of life yielding new species that differ from existing ones. Speciation: one species splits into two or more species. Besides merely looking a morphology (body form) one needs to look at a more discrete form (dna sequences). Species a group of populations whose members have the potential to interbreed and produce viable, fertile offspring *don"t produce viable, fertile offspring with other groups. Absence of gene flow results in formation of new species. Formation of a new species depends on reproductive isolation. Gene flow ongoing exchange of alleles holds alleles of populations together. Reproductive isolation existence of biological factors that prevent members of two species from interbreeding and producing viable, fertile offspring. It takes several factors to block gene flow. Reproductive barriers between closely related species are not obvious. Barriers classified according to when they occur (before or after fertilization)
