On Cousinhood
Assured of Man’s
supremacy?
Oh silly sibling,
don’t be smug!
For great and wide’s
our family tree;
Dear sister seaweed,
brother bug!
First cousins are those who share a grandparent; second
cousins share a great-grandparent; in general Nth cousins share an
great^(N-1)-grandparent; or in other words share a parent N+1 generations
back. Therefore siblings are zeroth
cousins, and one is one’s own negative first cousin!
For what value of N are all human beings Nth cousins? This is
a matter of evolutionary history. The present human species is about 200,000
years old, and at about 20 years per generation, that comes to 10,000
generations; so I would guess that we are at most 10,000ths cousins of each
other; and probably much less. There is
some genetic evidence of genetic bottlenecks in human prehistory; so I would
guess that we are at most 7000th cousins of each other, probably much less.
And what of other species? I found the following figures at
the site www.evogeneao.com
chimp = 240,000th cousin
gorilla =
310,000th cousin
cat = 27,000,000th cousin
cow = 28,000,000th cousin
robin =
170,000,000th cousin
frog = 175,000,000th cousin
fish = 195,000,000th cousin
snail =
300,000,000th cousin
dragonfly =
300,000,000th cousin
octopus = 300,000,000th cousin
According to that website, one can’t properly define
cousinhood for bacteria. If we did, then I suppose that we’d be zillionth
cousins to redwood and mildew, for some absurdly high value of zillion.
In any case, it’s nice to have such a big and talented
family. Blessings, cousins!