BIOLOGY 1M03 Lecture Notes - Lecture 12: Sympatric Speciation, Allopatric Speciation, Apple Maggot
Document Summary
If there is a barrier to gene flow = allopatric speciation. But if no barrier, sympatric populations - populations that live in the same place - can become isolated. This requires strong natural selection acting on each population differently (cid:1) (cid:1) Sympatric speciation: speciation that occurs when gene flow is possible but not occurring. Usually scene as impossible but in some cases it can happen. Live in same habitat but specialize on different fruits. Host shift from hawthorns to apples is likely the first step in sympatric speciation (cid:1) (cid:1) (cid:1) (cid:1) Host shift is likely the first step in sympatric speciation. Especially in insects (over 3 million species of insets, and they usually are associated with a specific host plants) This would be disruptive selection (selecting for the extremes) This would be considered separate species under the ecological species concept (cid:1) (cid:1) (cid:1) (cid:1) Polyploid: have more then two sets of chromosomes (more than diploid)
