I was on an evolution kick and also found a 3 part program on Nova called Becoming Human, all about the evolution of us. I can't give you the videos here, but I'm providing the links so you can watch them on PBS's site. They are very interesting, and were just aired on PBS in November, so they have some new ideas and research.
- Becoming Human Part 1: First Steps: Six million years ago, what set our ancestors on the path from ape to human?
- Becoming Human Part 2: Birth of Humanity: New discoveries reveal how early humans hunted and formed families.
- Becoming Human Part 3: Last Human Standing: Many human species once shared the globe. Why do we alone remain?
Exploring a bit further, I found an interesting article about human evolution called Are We Still Evolving? This is a question that I have been pondering lately. Since we developed agriculture about 10,000 years ago, developed medicines, learned to cook our food, and developed technology, among some factors, more and more babies survive and grow up to reproduce. According to the article, about 98% of all babies born in the U.S., Europe or Japan survive long enough to reproduce and pass on their DNA, so survival doesn't depend as much on genes.
But in third world countries, natural selection still favors mutations in dealing with deadly diseases. For instance, people with the sickle-cell mutation in the beta hemoglobin gene have a protection against malaria.
One example of more recent evolution in humans is lactose tolerance. This is evidence that we have evolved, even if it's just in a small but significant way.
Take the gene that confers lactose tolerance. For most of our history, our ability to digest lactose, the chief sugar in milk, turned off after weaning; we only drank our mother's milk. But after cattle were domesticated, cow's milk became a nutritious addition to the diet. Natural selection would have favored individuals born with a mutation that kept the so-called lactase gene switched on throughout life, enabling them to digest milk.
Genetic evidence shows that such a mutation first occurred in northern Europe perhaps 8,000 years ago. Recently, a team led by Sarah Tishkoff identified three new mutations, each conferring lactose tolerance, that arose in three different populations in East Africa. All were independent of one another and of the original European mutation. Nature seems be solving the same problem in different ways.
Well, science moves forward, and our ability to study genes in different populations around the world is improving and deepening. So hopefully we'll have more answers in the future about if we're still evolving. Here's the conclusion of the article:
In the end, the answer to the question of whether we're still evolving seems to come down to a matter of degree. And when you look at it that way, most scientists seem to be in basic agreement. That is, few would claim we're not evolving at all. The genetic evidence for natural selection—at least for mutations of single or at most a few genes that confer some benefit and thereby spread through a population over time—is just too strong, and it's getting stronger all the time.
By the same token, few would say we're evolving enough to become, say, the bulbous-headed superhumans of sci-fi anytime soon. Or, for that matter, enough to differentiate into one or more new species of human. Even saying unequivocally whether any or all of us are getting smarter is impossible say. As Pinker put it to me, "We're looking at a snapshot of ourselves, and we'd really have to run the movie for another few thousand years."
Still, it's a fascinating question that deserves attention.
Going further, 5 researchers speak a bit about Evolution in Your Life. The evolution of wolves to dogs, how humans became good runners, how the flu mutates so rapidly, how we use evolution to make better food, and how evolution helps solve crimes, is explored briefly in audio.
Now, here are the 5 videos I promised:
Growing Up In The Universe is a series of lectures by Dr. Richard Dawkins, Oxford professor. He presents five lectures on life, the universe, and our place in it. With brilliance and clarity, Dawkins unravels an educational gem that will mesmerize young and old alike. Illuminating demonstrations, wildlife, virtual reality, and special guests (including Douglas Adams) all combine to make this collection a timeless classic.
This is from 1991 but besides the antiquated computer technology, it's interesting and enlightening for young and old alike. You can buy all 5 hour long episodes on DVD from Dawkin's store.
Episode 1: Waking Up In The Universe
Episode 2: Designed and Designoid Objects
Episode 3: Climbing Mount Improbable
Episode 4: The Ultraviolet Garden
Episode 5: The Genesis of Purpose