Tuesday, April 13, 2004

tigons and ligers and bears, oh my!

And from what I was able to tell from the sites I read, all the great cats are interbreedable, although it's usually only the females that are fertile. Actually, even Felis domesticus, the common house cat, is interbreedable with the great cats, except primarily for difficulties involving size.

I find this terribly fascinating. It suggests to me that all the cats had a common ancestor, whether on the Ark on evolutionarily. If on the Ark, then speciation apparently can be a rather rapid process. Going with the young earth model, we're talking from one cat species into many in only 5,000 years or so.

Speciation would be fueled by adaptation and natural selection, as well as behavioral changes and various and sundry mutations and activations/deactivations of genetic sequences. Interesting, no? I've had to do some rethinking of my views on evolution as a result of this. Thank God my wife has a master's degree in it and can explain the different theories to me.

I find the whole thing interesting. For tigers, panthers, leopards, lions, cheetahs and so on to be interbreedable and capable of producing fertile offspring does suggest that they had a common ancestor. Evolutionarily that's what would be expected, but it's not exactly square with the standard creationist/young earth ideas, especially since it means that the species diverged that extensively in that short a time.

I'd also have to raise the question of whether this means the animals are evolving, or devolving. The Cat from which contemporary cat species are all descended presumably would have been one in which all the current genomes were present, which means the new species have lost a lot of their genetic diversity. It also means that the Cat was a versatile creature and spread to a number of very different habitats, and that many of its descendants or successors lack its adaptive ability. A panther can live in the rainforest, but a lion would have a hard time there, for example.

You can see a parallel in human development. We've settled into distinct racial or ethnic groups, but intermarriage is still possible among our many populations, probably because humanity has always been a free-ranging species and we're always going to other parts of the world and conquering the people already there. I mean, look at Europe: conquered by the Greeks, the Romans, the Germans, the Huns, the Moors, and that's still just the Middle Ages.

No comments: