BIOL 1202 Chapter : Ch 24
Document Summary
Concept 24. 1: the biological species concept emphasizes reproductive isolation. Defines a species as a population or a group of populations whose members have the potential to interbreed in natures and produce viable, fertile offspring. Cannot be applied to: asexual organisms, fossils, organisms about which little is known regarding their reproduction. Dependent on: reproductive isolation, genetic divergence. The existence of biological factors that impede members of two species from producing viable, fertile offspring. Prezygotic barriers: preventing the egg & sperm from coming together. Impede mating between species (habitat isolation) or hinder the fertilization of ova if members of different species attempt to mate. Postzygotic barriers: fertilization has occurred but there are other ways of preventing the production viable, fertile offspring, often prevents the hybrid zygote from developing into a viable, fertile adult. High levels of gene flow among populations must occur: we need low gene flow among populations to create reproductive isolations.
