Frinktopia, 11 May 2007

I Think It's Ironic That, For Once, Dad's Butt Prevented the Release of Toxic Gas

The new study indicated carbon that had built up in the oceans over millennia was released in two big pulses, one about 18,000 years ago and one 13,000 years ago....

While much of the CO2 released by the oceans after the end of the last ice age about 19,000 years ago was taken up by the re-growth of forests in areas previously covered by ice sheets, enough remained in the atmosphere to pump up CO2 concentrations significantly....

"The timing of the major CO2 release after the last ice age corresponds closely with deep-sea circulation changes caused by ice melting in the North Atlantic at that time," said Lehman. "So our study really underscores ongoing concerns about the ocean's capacity to take up fossil fuel CO2 in the future, since continued warming will almost certainly impact the mode and speed of ocean circulation."

"Since the uptake of CO2 on Earth's land surface is being offset almost entirely by the cutting and burning of forests, any decrease in the uptake of fossil fuel CO2 by the world's oceans could pose some very serious problems," Lehman said.

The (super-simplistic) implication: if anthropogenic warming raises the rate of melting in the North Atlantic, and it disrupts the global current (as has been hypothesized), then the deep oceans may 'burp' a great deal of stored CO2 into the atmosphere, adding to the vast quantities already put there by people:

Today, CO2 levels are higher than at any time in at least the past 650,000 years....

Humans have pumped an estimated 300 billion tons of carbon into the atmosphere since the Industrial Revolution, and the oceans have taken up about half of it, said Lehman.

Why Is This Still a Question?

How did the worldwide population of Homo erectus get replaced by Homo sapiens sapiens?

The older modern hypothesis is multiregional evolution, in which local populations worldwide just sort of 'morphed' erectus into sapiens, with just enough gene flow to keep them part of the same species. The younger, and more generally accepted hypothesis, is the out-of-Africa one, in which H. sapiens evolved in a single location in Africa and then spread throughout the world.

The multiregional hypothesis was developed to explain (coughjustifycough) human 'racial' differentiation. The problem is, there ain't no such thing. (I was surprised to find that 84% of biologists agree that there is, but then I thought [1] there's probably a much higher use of race in the purely denotative sense, and [2] what makes cell biologists, for example, qualified to answer this question? All biologists specialize, and human population biology can be quite complicated. And, of course, there's the simple explanation that they can be wrong just as easily as non-biologists. Just because they should know better doesn't mean they do.) If races were evolutionarily real, we would expect them to have identifiable evolutionary histories. But they don't: although Kennewick Man, for example, does look MORE like modern Southeast Asian and Oceanic populations than any other, he is still an "outlier relative to modern human populations." Probably a better way to put it is that he is least different from modern SE Asian and Oceanic populations than from other modern populations, not that he 'resembles' the former. Plus, that doesn't address the question of what K-man–contemporary SE Asian and Oceanic populations looked like: did he resemble his contemporaries more than the moderns? That's the $64,000 racial-evolutionary question.

The other major problem with the multiregional-evolution hypothesis is that that's not how speciation works. It would be an evolutionarily unique situation in the history of life on Earth, unlike the single-location event hypothesized in the out-of-Africa model. And then there's the so-called 'mitochondrial Eve' data that, on balance, seem to fit the out-of-Africa model better.

So I don't know why multiregional evolution won't just die. One can hope, though, that it is just a matter of time. (Also, I expect it'll fall by the wayside when Milford Wolpoff dies. And, unless he knows something the rest of us don't, that is definitely just a matter of time. Nothing personal; just stating the obvious.)

And, still speaking of early hominids (yes, hominid, dagnab it! I'll be deep in the cold, cold ground before I use that other word),...




Why Is This Surprising?

Early Humans Dug for Food, Study Suggests.

Wow, really, no foolin'; hey, I wonder what's on TV tonight....

(Ever notice the selectivity of null-hypothesis testing? Assumption is still alive & well in science.)




StarDate 1523-0901

"Surprisingly, it is very hard to pin down the age of a star"

Actually, I'm not surprised at all. To the contrary, I'm surprised that it's even possible, at least when you're doing it with a telescope from however far away it is (evidently, nobody cares how far away it is. It's less than 150,000 light years away because it's in our galaxy and that's an outlying outside estimate of our galaxy's diameter).


Can't Count: one commentor on this story had this to say:

...it is 13.2 billion years old — given that the universe is 13.7 billion years old, this star was literally born at the dawn of time.

Ummm, no: 13.7 billion - 13.2 billion = 0.5 billion, or 500 million. Given that it's 500 million years younger than the universe, when it "was literally born" is 500 million years after than the dawn of time. For comparison, 500 million years is about 80% of the time that there have been land animals on Earth, or twice as much time as has passed since the first dinosaurs appeared: a bit more than a drop in the universal bucket.