1. Historical Biogeography CH 7

2. Current Distribution Result of the interaction of: – Early history and place of origin – Fragmentation of continents – Climactic changes during Cenozoic – Cooling and eventual ice age in Pleistocene – Mass extinctions and adaptive radiations – Land Bridges Bering Greenland

3. I.Deep Time Perspective A.4 Zoic Eras B.Overview of Major Events C.Historic Biogeography

5. Table 25-1b

6. The rise and fall of dominant groups reflect continental drift, mass extinctions, and adaptive radiations

7. South America Pangaea Millions of years ago 65.5 135 Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present Continental Drift At three points in time, the land masses of Earth have formed a supercontinent: 1.1 billion, 600 million, and 250 million years ago Earth’s continents move slowly over the underlying hot mantle through the process of continental drift Oceanic and continental plates can collide, separate, or slide past each other Interactions between plates cause the formation of mountains and islands, and earthquakes

8. Mass Extinctions The fossil record shows that most species that have ever lived are now extinct At times, the rate of extinction has increased dramatically and caused a mass extinction In each of the five mass extinction events, more than 50% of Earth’s species became extinct Dimetrodon Hallucigenia

9. Fig. 25-14 Total extinction rate (families per million years): Time (millions of years ago) Number of families: Cenozoic Mesozoic Paleozoic E OS D C P Tr J 542 0 488444416359299251 200 145 Era Period 5 C P N 65.5 0 0 200 100 300 400 500 600 700 800 15 10 20

10. Adaptive Radiations Adaptive radiation is the evolution of many new species adapted from a common ancestor upon introduction to new environmental opportunities (new niches) Occurs via: – Evolution of novelty (i.e., seeds) – After a mass extinction (i.e., mammals) – Formation of new land (i.g. islands) – Piggyback on other organisms (insect radiations follow flowering plants) BASICALLY, any time many new niches (ecological livelihoods) are available, there is opportunity for adaptive radiation.

11. Table 25-1a

12. III. Multicellular Life - Neoproterozoic

13. Table 25-1a

14. V. First Life on Land VI. Conquest of Land Challenges: structural support dehydration reproduction Solutions: exoskeleton, lungs in animals what about plants? cuticle, stomata, vascular tissue, pollen – not all at once

15. Table 25-1a

16. Massive extinction – 250mya followed by adaptive radiation

17. Table 25-1b South America Pangaea Millions of years ago 65. 5 135 Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present VIII. Emerging Modern Lineages Triassic/Jurassic: global warming, arid Pangaea interior, mountain formation Reptiles loved it!

20. Table 25-1b South America Pangaea Millions of years ago 65. 5 135 Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present Extinction

21. Fig. 25-17 Millions of years ago Monotremes (5 species) 250 150 100 200 50 ANCESTRAL CYNODONT 0 Marsupials (324 species) Eutherians (placental mammals; 5,010 species) Ancestral mammal

22. South America Pangaea Millions of years ago 65.5 135 Mesozoic 251 Paleozoic Gondwana Laurasia Eurasia India Africa Antarctica Australia North America Madagascar Cenozoic Present Mountain ranges: Himalayans, Rockies (Eocene), Sierra Nevada (Miocene), Cascades, Coast ranges (late Miocene)

25. Great American Interchange Panama Isthmus formed 3 mya Panama bridge 26 genera S 12 went N Tapirs/llamas went extinct in N Am, so disjunct w/Asian