Allopatric Speciation Population with no geo isolation Allopatric Speciation Fairly common Dependent on geographic location Started with 1 population then split by river See picture o Genetic divergence occurs o Over time speciation occurs Sympatric Speciation No geographic isolation Organisms occur together Something happens o Gene flow mating little genetic divergence o Take gene flow to a 0 o Increase in likelihood of genetic divergence o Could be through mutation Causes immediate isolation Example snail morphology Mutation causes snail s shell to be coiled in the opposite direction Male and female parts no longer match up 1 gene mutation o Mechanical Isolation o Can also occur through changes in breeding behaviors locations o Behavioral isolation ecological isolation o Example Fruit Flies o Example Anoles Permanently isolates populations which increases genetic divergence which leads to speciation Breed with specific behaviors and places Breed on Hawthorn tree but something cause some flies to breed on an apple tree Now there is genetic divergence because they breed in different places Get to islands on driftwood One started on the tree and then there was a lot of competition so some moved to the ground and only bred there Gradualism slow rate of speciation o Intermediate forms before full speciation Punctuated Equilibrium o Rapid speciation o Short bursts of evolutionary change o Often mutation Extinction o Species loss there are more extinct species than currently living species o Gradually Changes in habitats anthropogenic or drought famine o As species are lost niches open up for other organisms to move into due to decreased competition Could lead to genetic divergence o Catastrophe hurricanes asteroids Example Sumatra Deforestation Example Chicxulub Crater Asteroids collide with Earth Cretaceous calamity New organisms move into the niches CHAPTER 23 Systematics Method of classifying naming Organisms within an evolutionary framework Goals o Inventory of all living things o Universal system for naming taxonomy o Determine evolutionary relationships between organisms Carolus Linnaeus Systema Naturae Derived binomial nomenclature o Genus species Homo sapiens In Latin universal language for describing organisms Hierarchical Nomenclature o Kingdom Phylum Class Order Family Genus Species o Used to organize group organisms o Based on structural similarities differences Carl Woese Added Doman above Kingdom 3 Domains o Bacteria Archaea Eukarya o Bacteria and Archaea lack a membrane bound nucleus prokaryotes o Eukarya have a membrane bound nucleus
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