Sap is thicker than water:
Nature expects you to take care of some basics. Breathe, seek food, water, shelter and have sex.
The drive to do each of these is very strong. They can all be postponed, but not indefinitely. Sex is very important. In fact without it, so far as nature is concerned, there is not much point in the others taken altogether. Oh well, yes, I suppose you can contribute to your society, and if that means keeping the society alive that’s something. But somebody needs to be having babies. Otherwise nature pulls the plug out on the whole group.
But you need to have sex with the right person. If too many people make bad choices, in this case meaning choosing mates who are not related for many generations back, it means no babies. And the group might just as well stop breathing. The final result is the same.
So if there is something that is so dreadfully important, you would think there would be a massive instinct to do it. The instinct should be as strong as other vital drives.
That means we must be able to recognize, our kindred. In fact all animals must, one way or the other.
The redoubtable hbd chick, of whom I have spoken, turned up a reference that seems to seal the case.
Plants can recognize kin.
http://hbdchick.wordpress.com/2011/04/11/even-plants-do-it/
There is an annual plant called “Cakile edentula.” It will compete for root space with other plants unless they are siblings.
There you have it. It’s real. Of course being courteous with ones roots is not exactly the same as seeking kin for mates, but the instinct is in there somewhere. Find it.
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