Review of Elaborate: Building Bridges

# of different mammals 10 11 8

Look for fossil remains in the oldest layers Look for fossil remains in the oldest layers. Endemic animals/plants are only found in a specific region of the continent or can be widespread with the continent, but nowhere else. Columbia & Argentina (oldest strata), then compare to N. America sites of same age. Search bottom of strata as animals may have later migrated.

Endemic to S. America or N. America Endemic to S. America or N. America? Look at lower (older) strata for clues!

Re-write question 6c to say: List the mammals that were endemic to South America and might be endemic to North America Armadillo Opossum Capybara Sloth porcupine Horse Cat Dog Rhinoceros Camel glyptodont Mammoth Maybe some or all N. America mammals had migrated from other continents (Eurasia) via a land bridge in Bering Sea.

Evidence? Armadillo Capybara Opossum Sloth Arrived about 4 mya. Land bridge (Central America) was formed. 2 mya Via Central America land bridge!

10-11 mya Spread from Arizona to Mexico to other locations but not S. America. Extinct after 5 mya. 2 mya in New Mexico. Didn’t migrate to S. America. Why not?

Nazca, Cocos & Caribbean plates Central America At least 4 mya. That’s when the first migrants (e.g., armadillo & capybara) showed up in N. America All used except mammoths & Rhinoceroses Nazca, Cocos & Caribbean plates

Skip boundaries Convergent Uplift, as well as volcanoes that formed from subduction of Cocos and Nazca plates beneath the Caribbean Plate.

Include tectonic ideas, like: plate movement, uplift (mountain forming), climate (i.e., subtropical vs temperate), dinosaurs (reptiles) vs mammals… What do you think? What do you know about mountains… exposed to the elements for millions of years… Cross out #4