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Speciation and Extinction

Speciation and Extinction. Questions for Today:. What needs to happen for new species to form? How old is the Earth and how do we measure it’s age? What are the major types of Extinctions? What are the 5 Major Extinctions and what are their causes?. How do New Species Evolve?.

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Speciation and Extinction

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  1. Speciation and Extinction

  2. Questions for Today: • What needs to happen for new species to form? • How old is the Earth and how do we measure it’s age? • What are the major types of Extinctions? • What are the 5 Major Extinctions and what are their causes?

  3. How do New Species Evolve? • Speciation is when two species arise from one. • A new species is formed when some members of a population can no longer reproduce and produce fertile offspring. • There are two common mechanisms for speciation: • Geographic Isolation • Reproductive Isolation

  4. How do New Species Form • Geographic Isolation • When one population has been physically separated into two groups. • Mountain Ranges, Roads, or streams • Reproductive Isolation • After a long period of geographic isolation, two species can no longer interbreed. • From 100 years to tens of thousands or millions of years.

  5. How do new species Evolve? • Humans can also affect the way species of evolve. • Artificial Selection and Genetic Engineering • Selective Breeding • GMO crops

  6. Geologic Time • Paleozoic Era (540 – 248 mya) • Cambrian Period 540-500 mya • Ordovician 505-438 • Silurian 438-408 • Devonian 408-360 • Carboniferous 360-280 • Permian 280-248

  7. Geologic Time • Mesozoic Era (248-65 mya) • Triassic (248-208) • Jurassic (208-146) • Cretaceous (146-65) • Cenozoic Era (65 – present) • Tertiary (65 – 1.8) • Quaternary (1.8 – today)

  8. Extinction is Forever • Extinction occurs when one or more species cannot adapt to the environment and die out. • They cease to exist • Occurs primarily in endmeic species • Species that are located primarily in one area.

  9. Extinction can affect one or many • Two types of extinction: • Background Extinctions • When a population dies out over a long period of time. • The annual background extinction rate is one to five species for each million species on earth. • Mass Extinctions • When a large group of species (25%-70%) are wiped out in a geologic period lasting up to 5 million years. • Caused by catastrophic, widespread events

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