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Wildlife Diversity and Adaptation

Darwin’s plant research expanded on his theories of wildlife diversity and adaptation. During his travels as a naturalist on the HMS Beagle from 1831 to 1836, Darwin observed flightless birds on three continents and separate islands: the rhea, ostrich ,cassowary, emu, and kiwi. He postulated a common ancestry for them, but could not account for their distribution. Could you?


Rhea - South America Ostrich - Africa Cassowary Emu Brown Kiwi
Rhea
South America
Ostrich
Africa
Cassowary
Australia
Emu
Australia
Kiwi
New Zealand

Fossils discovered later showed even stranger distributions of physically similar plants and animals than Darwin had anticipated – and no evidence of the land bridges that some had suggested would explain the widespread distributions. (Drawing of fossil organisms’ distribution by US Geological Survey)
continental drift

In the decades after Darwin’s death, geomagnetic evidence has piled up to explain how related species became so widely distributed. The continents built up on huge tectonic plates on the earth’s molten core that moved over geologic time and are still moving today.
Continental Drift
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