Sunday, January 22, 2012

Why do turtles travel across the ocean? And what of the recurrent laryngeal nerve?

A really magnificant description of an ancient behavior:
"I was told some years ago that the reason why some species of sea turtles migrate all the way across the South Atlantic to lay their eggs on the east coast of South America after mating on the west coast of Africa is that when the behavior started, Gondwanaland was just beginning to break apart (that would be between 130 and 110 million years ago), and these turtles were just swimming across the narrow strait to lay their eggs. Each year the swim was a little longer—maybe an inch or so—but who could notice that? Eventually they were crossing the ocean to lay their eggs, having no idea, of course, why they would do such an extravagant thing.

What is delicious about this example is that it vividly illustrates several important evolutionary themes: the staggering power over millions of years of change so gradual it is essentially unnoticeable, the cluelessness of much animal behavior, even when it is adaptive, and of course the eye-opening perspective that evolution by natural selection can offer to the imagination of the curious naturalist." -Daniel Dennett

In mamillian anatomy there is a similar such detour that seems absurd in the absence of evolution:  the recurrent laryngeal nerve.  Watch a video about it here:

1 comment:

Anonymous said...

Hey nick! hows it going!?. Havent checked your blog in quite some time. Looks like your still updating and stuff. Awesome. Im going to read some high quality nick material. Anyway, talk to you later, mike.