7 - BIO LECTURE NOTES (1/21/09) Phylogenetic trees, fossil...

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BIO LECTURE NOTES (1/21/09) Phylogenetic trees, fossil record Review of lecture 4 o Definition of species – idea of species is natural and old. Almost all peoples recognize different species Different groups of organisms that are evolutionary independent lineages Biological species concept – reproduction isolation Morphological species concept Phylogenetic species concept – separate branches on pa phylogenetic tree Subspecies o Geographic speciation Dispersal and colonization isolate populations Vicariance events isolate populations – e.g. continental drift separates ritate birds o Sympatric speciation Can selection alone cause speciation? Beak length of soapberry bug example. Polyploidy – e.g. naval orange, seedless grape are tetrapolid How can polyploidy lead to speciation? o A mutation that results polyploidy – the condition of having more than two sets of chromosomes – can cause speciation, particularly in plants o Polyploidy can lead to reproductive isolation Reading a phylogenetic tree o Branches represent populations through time. Adjacent branches are sister
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7 - BIO LECTURE NOTES (1/21/09) Phylogenetic trees, fossil...

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