One of the 'themes' you need to think about, when studying human evolution, is dispersal - just how did human populations spread about the globe, and when did they do it? In September this year a group of scientists got to together to talk about how and when humans might have become seafarers.
November 2007 Archives
The university has an e-subscription to the journal Science, so each week we get details of the latest issue via e-mail. I was scrolling through one of the July issues when an article's title caught my eye: Aspens return to Yellowstone, with help from some wolves. Really? I thought. What have wolves got to do with trees growing??
One of the neat things that have come from advances in molecular biology is our ability to use DNA technology to tease out evolutionary relationships - especially those that aren't immediately obvious (such as the subject of an earlier post). Now here's another example - an animal that looks superficially like a worm - but turns out to be most closely related to sea anemones, jellyfish, & other radially-symmetrical animals.
I've just had an e-mail from Emma, who writes: I'm getting really confused about Punctuated Equilibrium and Gradualism... do both operate at once? Or do some scientists argue for one and some argue for the other?
Scientists have thought for a long time that tree shrews are the closest living relatives of primates. More recently, use of DNA data together with morphological comparisons suggested that colugos are also very closely related to apes, monkeys (& us). These so-called 'flying' lemurs use extensive flaps of loose skin, stretched between their outspread front and back legs, to glide from tree to tree. A paper recently published in Science has attempted to sort out the relationship between these three groups.
I was idly looking at my page this morning & thought, it might be quite fun to tell you the story behind the picture (yes, that really is me; my husband took the photo in nineteen-mumbley-mumble). That is, how (& why) did I become mother to a bunch of little swans? It's a long story...
I like to teach my students here at Waikato something about how the theory of evolution was developed. OK, I'm interested in history anyway, but it's also a really good way to teach about the nature of science. You know; what is science, really? What does the word theory mean to a scientist? How's science done? Well, I've just come across a website that has some really good material on just these issues.
I remembered, after my last post, that there's an excellent book that puts domestication of plants and animals into a global perspective and asks, among other things, why it was europeans who got into building large overseas empires, not people from other parts of the world. It's Guns, Germs and Steel, by Jared Diamond (1998), & I recommend it; it's a really good read & very thought-provoking.
Anyway, back to the plants...
When did humans first domesticate plants? Well, humans living in what is now known as Turkey had domesticated wheat by 10,500 years ago. How can we be so sure of this date?
Sometimes we think of human evolution as being distinct from the evolution of other animals. I think it important to remember that it's not, and that our own evolutionary history follows the same patterns, and is shaped by the same processes, as the history of all other living things.
Well, I've finally made it up to Auckland, to go to the 'Darwin' exhibition at Auckland War Memorial Museum. And it's as good as I'd hoped. If you live in Auckland, or you're visiting, do try to go & see it. It's a wonderful walk through Darwin's life and through his development of the theory of evolution.
You'e probably come across the terms 'microevolution' and 'macroevolution'. 'Microevolution' is generally taken to mean small-scale changes in a population's gene pool, while 'macroevolution' is evolutionary change at the level of species, or genus, or phylum. This distinction can cause problems with understanding...