BIS 2B Lecture Notes - Lecture 14: Stamen, Zygote, Species Problem

• School: UC-Davis
• Department: Biological Sciences
• Course: BIS 2B
• Professor: strauss,gerhart

Document Summary

Biological species concept: group of organisms reproductively isolated in nature to produce fertile offspring. Horses and donkeys mate to make mules that are infertile so horses and donkeys are not same species (like ligers) Can"t apply to extinct organisms b/c can"t be studied. Can"t apply to asexual since you can"t figure out who is mating with whom. Can have subspecies if relationship isn"t well understood. Asexual mating/extinct animals, don"t always have mating data, complexity of mating systems. Phylogenetic species concept: a species is a group of organism that share common ancestor, can be distinguished from other by particular traits. Good for groups where other data is limited. Prezygotic barrier: prevents fertilization if mating is even successful. Habitat isolation: occupy diff habitats so they don"t meet. Ecologically: if occupying diff niches in same habitat like diff fish mating in different areas. Different coral spawn at different times and released eggs/sperm don"t mix. Behavioral isolation: don"t recognize one another as potential mates.