Hybrid Zones -What can happen when new or partially formed species come into contact

Hybrid Zones Reveal factors that lead to reproductive isolation Happen when species have not become 100% reproductively isolated Located where two species meet

3 Possible outcomes of hybrid zones Reinforcement of barriers Fusion of species Stability

Fusion Example

Rate of Speciation Does speciation happen gradually or rapidly Punctuated Equilibrium Gradualism gradual accumulation of small changes over long time rapid bursts of change mixed with long periods of little or no change

Gradualism vs. Punctuated Equilibrium gradual divergence over long spans of time assume that big changes occur as the accumulation of many small ones Punctuated Equilibrium rapid bursts of change long periods of little or no change species undergo rapid change when they first bud from parent population