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Speciation. evolution of a new species occurs when members of similar populations no longer interbreed to produce offspring in a natural environment. In order for their to be speciation, there must be isolation. Geographic isolation - when a physical barrier divides a population volcano
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Speciation • evolution of a new species • occurs when members of similar populations no longer interbreed to produce offspring in a natural environment
In order for their to be speciation, there must be isolation
Geographic isolation - when a physical barrier divides a population • volcano • earthquake (produce islands) • flood
Gene pools will evolve separately • can become different enough to be separate species
Reproductive isolation • Populations can no longer produce fertile offspring • genetic material can be so different that reproduction is not possible
Behaviors can also prevent reproduction • mating at different times of the year
1) Convergent evolution • distant related organisms evolve similar traits • develop structures for the same function • analogous structures
2)Divergent evolution • pattern where species that were similar to an ancestral species become more distinct • become less alike as they adapt to separate environments • homologous
adaptive radiation - a species adapts into a variety of species to fit many diverse habitats • Finches’ beaks adapted to food sources on Galapagos Islands
ADAPTIVE RADIATION –An example of divergent evolution http://www.vanderbilt.edu/AnS/english/Clayton/Galapago_finches.gif http://evolution.berkeley.edu/evolibrary/home.php
Artificial Selection • Breeding organisms for desired traits • Agriculture (plants and livestock) • Dogs and other pets