It is well documented that Thomas Robert Malthus’ An Essay on the Principle of Population greatly influenced both Charles Darwin and Alfred Russell Wallace’s independent conception of their theory of natural selection. In it, Malthus puts forward his observation that the finite nature of resources is in conflict with the potentially exponential rate of reproduction, leading to an inevitable struggle between individuals. Darwin took this basic premise and applied it to nature, as he notes in his autobiography:
In October 1838, that is, fifteen months after I had begun my systematic inquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The results of this would be the formation of a new species. Here, then I had at last got a theory by which to work.
The interaction of demographic and evolutionary processes is thus central in understanding Darwin’s big idea: that exponential growth will eventually lead to a large population, and in turn will generate competition for natural selection to act on any heritable variation which conferred a greater fitness advantage. Under these assumptions we are able to interpret the evolutionary record of most species by appealing to two basic causal elements: genes and the environment. As we all know, in most cases the environment generates selection pressures to which genes operate and respond. For humans, however, the situation becomes more complicated when we consider another basic causal element: culture. The current paper by Richerson, Boyd & Bettinger (2009) offers one way to view this muddied situation by delineating the demographic and evolutionary processes through the notion of time scales:
The idea of time scales is used in the physical environmental sciences to simplify problems with complex interactions between processes. If one process happens on a short time scale and the other one on a long time scale, then one can often assume that the short time scale process is at an equilibrium (or in some more complex state that can be described statistically) with respect to factors governed by the long scale process. If the short time scale and long time scale interact, we can often imagine that at each time step in the evolution of the long time scale process, the short time scale process is at “equilibrium.” A separation of time scales, if justified, makes thinking about many problems of coupled dynamics much easier.
In recent times, genetic technology has progressed sufficiently to elucidate upon some of the questions normally preserved for archaeologists. One such question concerns the fate of a group of hominins that roamed Europe and East Asia for at least 250,000 years. During this time, this species adapted and endured some of the harshest environments on offer, all while showing signs of a unique culture. Only for them to suddenly disappear from the fossil record approximately 30,000 years before present (BP) (cf. Barton et al. 2007). So, what happened to our closest evolutionary relatives, the Neanderthals?
As many of my friends will know, I’m quite a big fan of Richard Dawkins. But for some reason his website seems to spawn an army of what can only be described as mildly irritating atheists. A particular aspect I frequently bemoan is the necessity of some members to contort a fairly innocuous article into some anti-religious rant. Honestly, it’s unceasing. Take for example this article discussing Neanderthals. Just scroll down to the comments and you’ll be greeted with:
It all just gets you thinking about why the Neanderthals died out. I’ll theorize that their bigger brains found our ancestors’ ravings about our divine origins totally hysterical — and the resulting campaign of genocide simply took the poor buggers off guard.
Funny, yes? Well, no, not when the same joke/theme/structure is applied over and over again. I’ll throw out some more, as I don’t want to single out one individual:
I like to imagine science as a massive guillotine, with creationists frantically trying to stick objects to stop it’s progress. Science may be moving somewhat slowly, but nothing can really stop its progress. (From an article about RNA as a precursor for life on Earth.)
At least one commenter was honest enough to give up any pretence of being interested in the article itself:
When you look at the big picture, Obama has a tough road ahead of him and needs to harvest the support of everyone in America, even that large swath of intolerant, evangelical America, who are Americans none the less. I can’t say that I agree with the choice but I understand it. ( About, um, Quantum computing…)
Maybe it’s a running joke? Or perhaps it’s what you should expect from a website run by Richard Dawkins? Personally, I find these comments serve as an effective cure for insomnia: their repetitive nature will guarantee instant sleep, plus you’ll probably learn something new (from the articles at least). Oh, and one more thing, what’s with Dawkins’ dvd covers: