Speciation The process by which one species splits into two or more species.
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Transcript of Speciation The process by which one species splits into two or more species.
Microevolution to Macroevolution
Biological Species Reproductive Isolation
A group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring
The existence of biological factors (barriers) that impede members of two species from producing viable, fertile, offspring
Reproductive Barriers
Prezygotic Barriers Postzygotic Barriers
Habitat IsolationTemporal IsolationBehavioral IsolationMechanical IsolationGametic Isolation
Reduced Hybrid Viability
Reduced Hybrid Fertility
Hybrid Breakdown
Speciation
Allopatric Sympatric
http://www.csus.edu/indiv/l/loom/preview%2027.htm
http://study.com/academy/lesson/sympatric-speciation-example-definition-quiz.html
Speciation Rates Vary
https://www.boundless.com/biology/textbooks/boundless-biology-textbook/evolution-and-the-origin-of-species-18/reconnection-and-rates-of-speciation-126/varying-rates-of-speciation-506-11732/
Five Major Extinctions (names & dates of these
extinctions are beyond the scope of this course and the AP exam)
Catastrophic Methane Release, Flood basalt
eruptions, Climate change, & Impact
Events.
http://www.bbc.co.uk/nature/extinction_causes
Possible Causes
http://www.deathreference.com/En-Gh/Extinction.html
The Five greatest mass extinctions
Ordivician-silurian
Late Devonian
Permian-triassic
Late Triassic
Final Cretaceous
When Occurred
439 million years ago
365 million years ago
251 million years ago
199–214 million years ago
65 million years ago
Casualties Up to estimated 85% species and 45–60% of marine genuses killed.
70–80% of all species and 30% of families vanish; marine life more decimated than freshwater and land fauna.
Most devastating of all, eliminating 85–90% of all marine and land vertebrate species, 95% of marine species. End of trilobites and many trees.
More than three quarters of all species and one quarter of families disappear. End of mammal-like reptiles and eel–like conodonts, leaving mainly dinosaurs.
47% of marine genuses and 18% of land vertebrates wiped out, including the dinosaurs, leaving mainly turtles, lizards, birds, and mammals.