BIO_SC 1010 Lecture Notes - Lecture 28: Species Problem, Zebroid, Zygote
Document Summary
Change in allele frequency in a population over time. When diversity between populations becomes so great, the populations will diverge & new species form. All life on earth shares a common ancestry. Different species emerged over time due to natural selection. Humans are unique as a species, but we share characteristics (dna) with other species. Speciation: process in which one species splits into two or more species. Biological species concept: defines a species as groups of populations whose members have the potential to interbreed with one another in nature & produce fertile offspring. Humans have quite a bit of diversity, but can still interbreed. Reproductive barriers: different species cannot mate due to anything that prevents individuals of closely related species from interbreeding. Prezygotic barriers: anything that prevents mating or fertilization (before a zygote can be made) Ecological (habitat) isolation, temporal (time) isolation, behavioral isolation. Postzygotic barriers: after interspecies mating occurs, if hybrids zygotes fail to survive or reproduce.