Sep 15 2009
Fun Science Fact: Evolution of the Human Heart
Wow. It seems the evolutionary precursor of the human heart was cold-blooded. And reptilian! In recent research a genetic link has been discovered between the hearts we’ve got in our chests and those found in lizards. Holy leapin’ scientific wizardry!
Here’s some background information, courtesy of ScienceDaily, one of the sites that carried the news release:
From an evolutionary standpoint, the reptiles occupy a critical point in heart evolution.
While bird and mammalian hearts have four chambers, frogs and other amphibians have three. “How did hearts evolve from three to four chambers?” [Benoit] Bruneau said. “The different reptiles offer a sort of continuum from three to four chambers. By examining them, we learned a lot about how the human heart chambers normally form.”
He explained that with four chambers—two atria and two ventricles—humans and all other mammals have completely separate blood flows to the lungs and to the rest of the body, which is essential for us to be warm-blooded.
And the discovery? Researchers at the Gladstone Institute of Cardiovascular Disease pin-pointed a/the gene responsible for change in heart formation. The Tbx5. Interestingly, and relevantly, this gene has also been linked to congenital heart disease.
[We now bring you a snarky freethought tangent:]
. . . So Gawd doesn’t hate the babies that come into the world with this birth defect. Whew! That would be a lot of hating. Roughly 35,000 children each year in this country are born with congenital heart disease.* Gawd just did a shoddy job guiding human evolution! Which makes more sense. Well, to somewhat more reasonable believers in god-nonsense it does.
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* Source
