Monday, October 28, 2013

Monthly Science Roundup #2

Once again an entire month managed to escape me! November should slow down, but in the meantime I have missed all of October's science updates and can't let that slide. So in the style of September's roundup, here are the top FOUR science stories of October, in no particular order:

1. Signals from the Big Bang

Hershel Space Observatory

Learning about the very beginning of the universe is obviously a bit of a challenge. But thanks to new data from the South Pole Telescope and the Herschel Space Observatory, science has taken another step closer to understanding the Big Bang.

When the Big Bang occurred, it left a radiation imprint on the universe, and a small percentage of this radiation occurs as polarized light. There are two modes of this light: E-modes and B-modes. We've found E-modes over a decade ago. B-modes have proven elusive, though, and--sadly--are also the version that would provide serious information on the initial gravitational waves that occurred during the massive "inflation" of the universe fractions of moments after the Big Bang.

But now they've detected some. As light twists, crossing the universe and getting deflected/pushed around by the gravity of galaxies and dark matter, it produces B-mode radiation. That's what has been now found, thanks to the work of many dedicated astronomers. What we're still waiting on is whether the even more primordial version of this B-mode radiation has been detected. That should be revealed in 2014.

2. Women Cave Painters

Turns out cave art wasn't a "guy thing", like has been predominately assumed. About three quarters of all cave paintings may have in fact been done by women, according to a new study.

By measuring the hand prints associated with cave paintings and analyzing them next to proportions of men and women's hands from populations of European descent, it was discovered that not only was there clear sexual dimorphism among the cave hand prints, there was also a predominance of female hands in the paintings.

These hand prints could mean anything, but a likely hypothesis is that they're used as an artist's signature. This gives an insight into early human culture that goes against common assumptions of gender roles in ancient groups. But it brings up a new question: why mostly women?

3. 441 New Amazon Species Discovered

On expeditions over the past four years have lead to the discovery of over four hundred new species in the Amazon rainforest. Of course, most of these are already in danger because of the environmental issues that region faces.

Among the new species include a piranha that doesn't eat meat, a flame-colored lizard, and perhaps most adorably, a monkey with babies that purr to one another. You read that correctly. Purring baby monkeys. If you get nothing else out of this blog post, I hope you at least have now smiled.

4. Single Species for ALL Early Humans?

Old American Museum of Natural History human evolution tree. Source.

This has been all over the news lately. A new skull has been found that has features so varying, that it seems to unite all species of early Homo (the genus of primate that humans belong to) into one single species. No more Homo rudolfensis vs Homo habilis. Just one united species.

First of all, the scoop: a new early human skull has been found in the Dmanisi region of Georgia. It's 1.8 million years in age, and is known as "Skull 5". It's preservation is spectacular. It's part of a group of skulls that are often thought of as the earliest Homo erectus, as it changed from Homo habilis.

Now take a look at the 2 million year mark on the picture above. See all the various "Homo" skulls at that time? They got split into different species based on features that are constantly argued over by paleoanthropologists. There's an age-old debate here.

Were these really different species? (Argument: modern primates have more than one species in their genus, why shouldn't we have had the same in prehistory?) Or were these different skulls all from one species that had a huge variation in skull shape? (Argument: species today can be wildly varying within their own bounds, so why not us?)

The new skull favors the second of the two arguments. And despite my eyebrow-raising at how it's been reported in the media (hype will always be hype), I'm not going to lie, this is very exciting stuff. The new skull has a variety of features shared with "different" species of Homo, young and old, and in particular, contemporary.

Basically, the traits of skull 5 should not all be in one skull. By our current understanding, and especially by the "different species" argument, they really shouldn't. And yet, here we are. Put it with the other skulls from the site, and it just makes it worse. None of that stuff should be together! Or so we thought.

John Hawks, anthropologist and web-blogger, sums it up best:

The entire early Homo sample has barely more variability than is found within the single Dmanisi site, at a single time.

What this means is that over the hundreds of thousands of years that Homo was kicking around as an early genus, at one single time at this one site, skulls have just as much variation among themselves as the entire lot of the rest of the stuff that's ever been found anywhere. Huh. Well then.

Imagine if you had never heard of Skittles, and then found a red Skittle. Maybe two. And then a couple days later, in a different place, you found a green Skittle. And maybe a week, later, a yellow Skittle in a different town. You might start assuming that each place has its own color Skittle, or that only certain colors show up at certain times. But then there's the day you discover an actual bag of Skittles. And you realize they all exist together. That's kind of what's happening here.

So it is a big deal. And it's messing with my brain, because I've always been a big fan of distinguishing Homo rudolfensis and Homo habilis. But as we've learned with Denisovans and Neanderthals, it is possible for different groups of humans to interbeed, even if they look different from one another or have other genetic distinctions. So there are ways of explaining this. I'm just not sure how to fold it into my personal version of our family tree just yet.


There were a ton of other cool stories this month that I wished I'd been able to highlight (one in particular, but I will get to that soon enough). Weekly Science Roundups will be back on track for November!

But first: SVP 2013.

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