BIOL 121 Lecture 14: Lecture 14
Document Summary
February 3, 2017: proposed that: each species is reproductive isolated from other species. (ernst mayr, 1942) evolutionary biologist expanded ideas of dobzhansky : (cid:862) pecies are groups of actually or potentially interbreeding natural populations whose individuals which are reproductively isolated from other such groups. (cid:863) Interbreeding (sharing a common gene pool) & produce fertile offspring. Ecological species: species are defined in terms of their ecological niches, focussing on unique adaptations to particular roles in a biological community. Bacteria: same species are likely to use same types of resources (sugars, vitamins) & grow under the same types of conditions (temperature, ph, etc. ) Prezygotic reproductive barriers: prevent mating or fertilization. Postzygotic reproductive barriers: prevent development of fertile adults. Species may occupy different habitats so they do not contact with each other: northwestern garter snake (thamnophis ordinoides) Moist meadows, open grassy patches: ribbon snakes (thamnophis proximus)
