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Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Summer 2006 Workshop in Biology and Multimedia for High School Teachers.

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Presentation on theme: "Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Summer 2006 Workshop in Biology and Multimedia for High School Teachers."— Presentation transcript:

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2 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Summer 2006 Workshop in Biology and Multimedia for High School Teachers

3 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. MASS EXTICTION & DIVERSIFICATION

4 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Chronology of Mass Extinctions Five major mass extinctions in the history of the planet Ordovician-Silurian Late Devonian Permian-Triassic End Triassic Cretaceous-Tertiary

5 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

6 Permission to use image granted by E O Wilson, Harvard University

7 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Timeline for Mass Extinctions Millions of Years Ago Ordovician-Silurian mya Late Devonian mya Permian-Triassic - 240mya End Triassic mya Cretaceous-Tertiary - 65 mya

8 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Organisms Affected by Massive Extinctions Ordovician - Silurian Late DevonianPermian - Triassic End TriassicCretaceous - Tertiary 25% Families 50% Genera 85% Species 22% Families 57% Genera 82% Species 53% Families 84% Genera 96% Species 22% Families 52% Genera 76% Species 16% Families 47% Genera 76% Species including the dinosaurs

9 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Percentage of Species Wiped Out Ordovician-Silurian - 85% Late Devonian - 82% Permian-Triassic - 96% End Triassic - 76% Cretaceous-Tertiary - 76%

10 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Major Indirect Causes for Mass Extinctions 1.Continental -Flood Basalt Lava (3 of 5) 2. Abrupt Falls in Sea Levels ( 1 of 5) 3. Asteroid Impact (4 of 5)

11 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

12 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Diversification and Speciation after Mass Extinctions Surviving Species take over vacant habitats and resources Speciation takes every 100 to 100,000 year 10 to 10,000 new species per year

13 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. PERIODONSETMAJOR EVENTSME PaleozoicCambrian540 Mamost animal phyla present, diverse algae Ordovician490 Mafirst jawless fishes, animal diversification1st Silurian445 Mafirst bony fishes, colonization of land Devonian420 Mafirst insects and amphibians, fish diversify2nd Carboniferou s 355 Maextensive forests, first reptiles, insects radiate Permian290 Mareptiles radiate, insects are diverse3rd MesozoicTriassic250 Maearly dinosaurs, first mammals, marine inverts. diversify 4th Jurassic200 Mafirst birds, diverse dinosaurs Cretaceous145 Maflowering plants and mammals diversity, dinosaurs continue diversification 5th CenozoicTertiary65 Maradiation of mammals, birds, flowering plants, pollinating insects Quaternary2 Ma humans evolve, extinctions of large mammals

14 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Phylogenetic Tree of Life

15 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College. Is there a potential Sixth Major Extinction? Species are becoming extinct at a rate of about 4000/year 100/day 1species every 15 minutes

16 Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College % of all species on the planet will be either endangered or extinct –Habitat destruction –Global Warming 25% mammalian species 15% bird species


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