Homo erectus and the paradox of human tools

Over the weekend, at the Earth Day tweetup at the Science Museum of Minnesota, I heard an interesting fact: Human beings are now the dominant agent of landscape change on this planet, more than any natural process. (That's right. Suck it, glaciers!)

We tend to think of this kind of thing as a result of modernity. But I think that's only partly true. Modern technology has given us the tools that enable us to change the landscape of Earth in massive ways we weren't capable of in the past. But throughout human existence—even before we were technically human—we have made relatively large alterations to the world. It's not like human beings woke up one day and thought, "Hey, it's the 20th century, let's start messing around with stuff!" In reality, what makes our modern impact on the planet different from past—other than scale—is mainly that we've developed more self-awareness about our impact on the planet, and have actually started talking about whether we like the side effects those impacts bring.

Case in point: A recent study of ancient African animal species that suggests our ancestors drove a huge proportion of fauna to extinction basically as soon as they were technologically capable of doing so. Here's how Ann Gibbons described it at Science Now:

After comparing fossils of 78 species of carnivores that lived during five different periods of time between 3.5 million years ago (when large carnivores were at their peak) and 1.5 million years ago, Werdelin found that all but six of 29 species of large carnivores (animals that weighed more than 21.5 kilos) had gone extinct in that time.

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Art and science: "Your Inner Neanderthal"

If you're in the Twin Cities area on Saturday, April 28th, I recommend going to check out artist and science geek Lynn Fellman talk about the Neanderthal contribution to the modern human genome, and how art can help people understand complicated science. "Your Inner Neanderthal" is part of the Hennepin County Library's DNA Days events. It's free, but you need to register. Read the rest

Inside a fossilized cell

Here's something that's just a little mind-blowing: Synchotron tomography, a type of medical imaging related to CT scanning, allows scientists to look inside the cells of fossils. Check out this post on Lawn Chair Anthropology about a recently published paper that used synchotron tomography to study clumps of fossilized cells and rule them out as being one of earliest ancestors. Read the rest

Did Neanderthals speak with a high-pitched voice?

Neanderthals had different bodies than we do. In general, they were stockier and shorter, for instance. And there were other physical differences, as well. It's hard to say what these differences meant in practice but it's fun to speculate. You could build up a pretty good about how those short, study bodies might have helped Neanderthals be better adapted to cold. Or, you could look at the shape of a male Neanderthal's voice box, and think about how that shape might affect the sounds that came out.

So that's what this video is about. I have no idea how widely accepted "high pitched voice theory" is. I couldn't find a lot of references to it outside of the BBC special this clip comes from. Here's what the BBC says:

Professor Bob Franciscus, from Iowa University, is part of a multi-national group attempting to do just that. By making scans of modern humans, he saw how the soft tissue of the vocal tracts depends on the position of the hyoid bone and the anchoring sites on the skull. Computer predictions were then be made to determine the shape of the modern human vocal tract from bone data alone. The same equations were then used with data from a Neanderthal skull to predict the shape of a Neanderthal vocal tract.

The Neanderthal vocal tract seems to have been shorter and wider than a modern male human's, closer to that found today in modern human females. It's possible, then, that Neanderthal males had higher pitched voices than we might have expected.

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