BIOLOGY 152 Lecture Notes - Lecture 30: Reproductive Isolation, Continental Drift
Document Summary
Reproductive isolating mechanisms evolve for reasons unrelated to speciation. Monday: april 4, 2016: the change is gradual, the change can reverse itself. What are the conditions for speciation to occur: genetic isolation the gene flow is restricted or blocked, evolutionary divergence genes will not flow back and forth from two different species. How can the isolation step occur: allopatric (aka. Geographic speciation) a population that is decided geographically. What is an island: an isolated piece of habitat which is surrounded by unsuitable habitat where organisms cannot reproduce. Biological islands: lakes, desert oasis, ponds, mountain tops. Different regions of mountains can be a biological island, depending on the climate of that specific location. Rising sea level isolates former part of mainland as an island. Geological change: ie. mountain building, river course changing. The outside of rivers is eroded and the insides are built up with gravel = two new land types for different species.
