Why did our species survive?

Today, we're the only living member of the genus Homo and the only living member of the subtribe Hominina. Along with chimpanzees and bonobos, we're all that remains of the tribe Hominini.

But the fossil record tells us that wasn't always the case. There were, for instance, at least eight other species of Homo running around this planet at one time. So what happened to them? What makes us so special that we're still here? And isn't it just a little weird and meta to be fretting about this? I mean, do lions and tigers spend a lot of time pondering the fate of the Smilodon?

Today, starting at 12:00 Eastern, you can watch as a panel of scientists tackle these and other questions. "Why We Prevailed" is part of the World Science Festival and features anthropologist Alison Brooks, genome biologist Ed Green, paleoanthropologist Chris Stringer (one of the key researchers behind the "Out of Africa" theory), and renowned evolutionary biologist Edward O. Wilson.

You can also join in a live conversation about the panel, which I'll be hosting. Just post to Twitter with hashtag #prevail, or join us at UStream. Read the rest

Bones of Turkana: Meave and Richard Leakey on human ancestors and the Leakey legacy

The Leakey family is like the Kennedys, but for paleoanthropology instead of politics. Think about any hominin fossil or artifact you can name. Chances are, there was a Leakey involved in its discovery. Louis Leakey was one of the first scientists to champion the idea that humans had their origins in Africa. For three generations now, his family has carried out active paleo excavations in eastern Africa, especially the countries of Tanzania and Kenya.

The first generation—Louis Leakey and his wife Mary—were most associated with Tanzania's Oldupai Gorge. But their son Richard, his wife Meave, and their daughter Louise have all spent their careers focused on Lake Turkana, on the border between Kenya and Ethiopia. The site is the world's largest, permanent desert lake. Undisturbed by modern development, in a spot where millions of years of flowing water have washed deposits and fossils down from the rift valley—Lake Turkana is an excellent place to search for human ancestors and our ancient relatives.

On Wednesday, PBS will air an hour-long documentary on the Leakeys' work at Lake Turkana. Part biography of Richard Leakey and part exploration of human history—Bones of Turkana will air May 16th at 9:00 pm central and again on May 21st at the same time. Yesterday, I got the opportunity to speak with Richard and Meave Leakey. We talked about human evolution, the scientific promise of Lake Turkana, the process of paleo fieldwork, and the lasting impression of the Leakey legacy. Read the rest

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.

Read the rest