8.2 Speciation Pages 336-340

Microevolution Changes in gene (allele) frequencies and phenotypic traits within a population and species

Species All members of a population with a common gene pool.

Reproductive Isolation A trait that prevents organisms from interbreeding -behavioural -structural -biochemical

Prezygotic mechanisms Behavioural Temporal Ecological isolation Mechanical isolation Gametic isolation

Postzygotic Mechanisms Zygotic mortality Hybrid inviability Hybrid infertility

Allopatric speciation Geographic isolation between members of the same species results in the evolution of two different species over time.

Sympatric Evolution A population evolves into two different species in the same geographic area. Example: Hawthorn flies

Polyploidy Ontario’s eastern green tree frog (4n) and Cope’s gray tree frog (2n)