Some kinds of DNA ancestry tests are basically astrology

If you want to learn about your family tree, you're probably better off doing the work of compiling history than getting a $500 DNA test.

How humans evolved to explore

Boldly going where nobody's gone before. In a lot of ways, that idea kind of defines our whole species. We travel. We're curious. We poke our noses around the planet to find new places to live. We're compelled to explore places few people would ever actually want to live. We push ourselves into space.

This behavior isn't totally unique. But it is remarkable. So we have to ask, is there a genetic, evolution-driven, cause behind the restlessness of humanity?

At National Geographic, David Dobbs has an amazing long read digging into that idea. The story is fascinating, stretching from Polynesian sailors to Quebecois settlers. And it's very, very good science writing. Dobbs resists the urge to go for easy "here is the gene that does this" answers. Instead, he helps us see the complex web of genetics and culture that influences and encourages certain behaviors at certain times. It's a great read.

Not all of us ache to ride a rocket or sail the infinite sea. Yet as a species we’re curious enough, and intrigued enough by the prospect, to help pay for the trip and cheer at the voyagers’ return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what’s there.

“No other mammal moves around like we do,” says Svante Pääbo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins. “We jump borders. We push into new territory even when we have resources where we are. Other animals don’t do this. Other humans either. Neanderthals were around hundreds of thousands of years, but they never spread around the world. In just 50,000 years we covered everything. There’s a kind of madness to it. Sailing out into the ocean, you have no idea what’s on the other side. And now we go to Mars. We never stop. Why?”

Why indeed? Pääbo and other scientists pondering this question are themselves explorers, walking new ground. They know that they might have to backtrack and regroup at any time. They know that any notion about why we explore might soon face revision as their young disciplines—anthropology, genetics, developmental neuropsychology—turn up new fundamentals. Yet for those trying to figure out what makes humans tick, our urge to explore is irresistible terrain. What gives rise to this “madness” to explore? What drove us out from Africa and on to the moon and beyond?

Read the full story

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. Moreover, the mass extinction began just before H. erectus appeared in the fossil record 1.9 million years ago. He also found that the community of carnivores alive 2.5 million to 2 million years ago ate a much broader range of food—with species within a community filling a wider range of dietary niches. By 1.5 million years ago, just hypercarnivores that ate only meat, such as lions and leopards, had survived while omnivores that scavenged and ate a wider range of foods, like civets, had disappeared. "Even I was surprised by the dramatic drop," Werdelin says.

Those omnivores that went extinct were in direct competition for scavenged carcasses with hominins.

This sounds kind of depressing, but I think it should actually make us feel a bit optimistic. Two million years ago, Homo erectus might have killed off 23 species of large carnivores. They had the tools to hunt and the desire to eat. But, even if they'd wanted to, those H. erectus wouldn't have had the tools necessary to organize other H. erectus' and better manage their own use of natural resources.

And that brings me to another interesting point that folks from the Science Museum of Minnesota kept making over and over at the Earth Day event. Modern life has created some pretty serious environmental challenges. But, at the same time, it's also put us in a much better position to deal with those challenges. Humans today are better educated, healthier, wealthier, and better connected with one another than any humans that have ever lived before. Our tools have helped us create some pretty big problems. But our tools are also exactly what we need to solve those problems.

Read the rest of the article at Science Now

Image: Homo erectus tools, a Creative Commons Attribution Share-Alike (2.0) image from hmnh's photostream