Dinosaur Files

How did dinosaurs, mammoths evolve exactly alike on two continents that split long before they became?

Pangaea split hundreds of millions years ago and certain dinosaurs, mammoths and people came about long after it. So what is the probability that both continents have the exact same animals?

Public Comments

1. they didn't.
2. The split of pangea happened slowly over hundreds of millions of years. The first major split was into two pieces and there were animals (amphibians and reptiles mostly) living here. These animals would have been separated on both continents, geographic isolation. Mammoths came much, much later when the continents are more of less what we see today. During the ice ages much of the ocean water was frozen so the shorelines were much lower and a land bridge connected Asia and North America across the Bering strait in Alaska. Anaimals were free to migtate to and from Asia as long as the land bridge was there. The idea that things can evolve in a similar manner is called convergent evolution. A good example of this is the eyes of the octopus and that of vertebrates. Completely unrelated genetically but evolved to meed same need.
3. There are some animals that are native to both North America and European Asian continent. Polar, brown and black bears and the wolf. Many marine animals. Several species of waterfowl. http://flora.huh.harvard.edu/china/novon/eaena.htm http://www.nearctica.com/butter/places/tundra.htm http://www.geocities.com/nowapan/mammal.htm
4. Dinosaurs didn't evolve "exacly alike" on two different, unconnected continents. They had a common ancestor that lived when the two continents were joined, and then they split to evolve into two (or more) different dinosaurs. With mammoths, they roamed during the ice age when the new world and the old world was connected at the Bearing Strait. They then evolved into different species in their respective continents. New world proboscidans (order that includes living elephants, mammoths, mastodons, dinotheres, and other "elephant-like creatures") are very different from the old worlds. http://en.wikipedia.org/wiki/Bering_Strait