The example I am going to give you today is about the evolution of spines for defense. Obviously the one that springs to mind is the hedgehog.
West European Hedgehog. Photo courtesy of Wikipedia.
There are sixteen species of hedgehog which are native to Europe, Asia and Africa, and all of these inherited their spiny defense from a common ancestor. However they are far from the only creatures to have evolved spines.
The Australian equivalent of the hedgehog is the echidna, or to be completely accurate, there are four echidna species all of which are found in New Guinea, and of these, only the short-beaked echidna is found in Australia. Nevertheless, whilst all four of these species will have inherited their spines from a common ancestor, this ancestor is vastly seperate from the common ancestor of the hedgehogs.
Short-beaked echidna. Photo courtesy of Wikipedia
Porcupines also have defensive spines, and are not closely related to the previous two examples. There are eleven old world species of porcupine, and twelve new world species of porcupine. What is fantastically interesting about these two groups of porcupines is that it seems that spines evolved separately in the old world and the new world.
Old World Porcupine. Photo courtesy of Wikipedia.
New world porcupine. Photo courtesy of Wikipedia.
The last example I’ll give you are the tenrecs. Tenrecs are mostly confined to Madagascar, and there are two species that have defensive spines, the greater hedgehog tenrec, and the lesser hedgehog tenrec. These two species look just like stretched versions of the more familiar hedgehog.
Unfortunately I can't find any pictures that I can use, so I insist you visit this link:
http://www.americazoo.com/goto/index/mammals/36.htm
So there you have it, five groups of animals that have all independently evolved a similar defense strategy in different places in the world. I’ll hopefully be able give you some more fascinating examples of convergent evolution in future.
Bye now!
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