Fascinating story told by Carl Zimmer, illustrated by yeast studies.
Scientists suspect that the first step towards a complex multicellular body like ours is for cells to evolve to live in primitive clumps. There may be a lot of advantages to living this way. It may be harder for a predator to eat you, for example. At the University of Minnesota, a team of scientists led by William Ratcliff and Michael Travisano figured out a way to create this kind of natural selection in a lab. As I reported last year in the New York Times, they were able to get yeast–which normally lives as single cells–to turn into simple multicellular clumps in a few weeks.
This is an incredible story. Scientists have identified a 30,000-40,000 year old hominid ancestor whose DNA indicates that it is part Human, part Neanderthal.
If further analysis proves the theory correct, the remains belonged to the first known such hybrid, providing direct evidence that humans and Neanderthals interbred. Prior genetic research determined the DNA of people with European and Asian ancestry is 1 to 4 percent Neanderthal.
Those were amazing times in Europe, where humans and Neanderthals co-existed. One wonders whether this co-existence was at all peaceful. Regardless, apparently I (along with many people of European and Asian ancestry) carry some Neanderthal genetic coding.
When I am asked about my “race,” I have sometimes (when I would not receive any sort of benefit or privilege for doing so) indicate “African.” I’ve previously argued that we’d all be better off declaring that we are African, because the categories or “race” are as scientifically deficient as they are culturally divisive. But now, thanks to this new finding, I have the option of indicating that my “race” is Part-human, part Neanderthal, out of Africa via Europe, currently living in the U.S. Or something like that.
It lived 66 million years ago, and it might be your ancestor:
Humankind’s common ancestor with other mammals may have been a roughly rat-size animal that weighed no more than a half a pound, had a long furry tail and lived on insects. In a comprehensive six-year study of the mammalian family tree, scientists have identified and reconstructed what they say is the most likely common ancestor of the many species on the most abundant and diverse branch of that tree — the branch of creatures that nourish their young in utero through a placenta. The work appears to support the view that in the global extinctions some 66 million years ago, all non-avian dinosaurs had to die for mammals to flourish.
In “The Parts of Life,” Karl Zimmer takes a close look at evolving computer networks and concludes that modules and minimal connections facility efficient evolution.
[A]s networks become more efficient, they become more modular. But once the parts of a system emerge, natural selection may then favor modules themselves, because they make living things more flexible in their evolution. Once life’s Legos get produced, in other words, evolution can start to play.
Anti-evolutionists like to point to the eye as though it is proof that God exists, in that the eye is so complex that it requires a designer. There are many problems with this argument. For instance, just because eyes are incredibly complex doesn’t mean that “God” exists–perhaps we just don’t know enough to explain eyes. The lack of an explanation is merely the lack of an explanation.
But we actually do know a lot about the evolution of eyes, as David Attenborough explains in this 3-minute video.
Daniel Dennett had this to say, at Edge.org:
The vision of the brain as a computer, which I still champion, is changing so fast. The brain’s a computer, but it’s so different from any computer that you’re used to. It’s not like your desktop or your laptop at all, and it’s not like your iPhone except in some ways. It’s a much more interesting phenomenon. What Turing gave us for the first time (and without Turing you just couldn’t do any of this) is a way of thinking about in a disciplined way and taking seriously phenomena that have, as I like to say, trillions of moving parts. Until late 20th century, nobody knew how to take seriously a machine with a trillion moving parts. It’s just mind-boggling.
The idea is basically right, but when I first conceived of it, I made a big mistake. I was at that point enamored of the McCulloch-Pitts logical neuron. McCulloch and Pitts had put together the idea of a very simple artificial neuron, a computational neuron, which had multiple inputs and a single branching output and a threshold for firing, and the inputs were either inhibitory or excitatory. They proved that in principle a neural net made of these logical neurons could compute anything you wanted to compute. So this was very exciting. It meant that basically you could treat the brain as a computer and treat the neuron as a sort of basic switching element in the computer, and that was certainly an inspiring over-simplification. Everybody knew is was an over-simplification, but people didn’t realize how much, and more recently it’s become clear to me that it’s a dramatic over-simplification, because each neuron, far from being a simple logical switch, is a little agent with an agenda, and they are much more autonomous and much more interesting than any switch.
The question is, what happens to your ideas about computational architecture when you think of individual neurons not as dutiful slaves or as simple machines but as agents that have to be kept in line and that have to be properly rewarded and that can form coalitions and cabals and organizations and alliances? This vision of the brain as a sort of social arena of politically warring forces seems like sort of an amusing fantasy at first, but is now becoming something that I take more and more seriously, and it’s fed by a lot of different currents.
I’ve posted on these issues before, but Dennett’s article advances the topic much further.
As usual, Florida is still undecided, a mess. According to NPR, though, it is leaning heavily toward Obama, despite the shenanigans of the state GOP in suppressing the vote.
I didn’t watch last night. Couldn’t. We went to bed early.
But then Donna got up around midnight and woke me by a whoop of joy that I briefly mistook for anguish.
To my small surprise and relief, Obama won.
I will not miss the constant electioneering, the radio ads, the tv spots, the slick mailers. I will not miss keeping still in mixed groups about my politics (something I am not good at, but this election cycle it feels more like holy war than an election). I will not miss wincing every time some politician opens his or her mouth and nonsense spills out. (This is, of course, normal, but during presidential years it feels much, much worse.) I will not miss…
Anyway, the election came out partially the way I expected, in those moments when I felt calm enough to think rationally. Rationality seemed in short supply this year and mine was sorely tasked. So now, I sit here sorting through my reactions, trying to come up with something cogent to say.
I am disappointed the House is still Republican, but it seems a number of the Tea Party robots from 2010 lost their seats, so maybe the temperature in chambers will drop a degree or two and some business may get done.
Gary Johnson, running as a Libertarian, pulled 350,000 votes as of nine last night. Jill Stein, the Green Party candidate, got around 100,000. (Randall Terry received 8700 votes, a fact that both reassures me and gives me shivers—there are people who will actually vote for him?)
Combined, the independent candidates made virtually no difference nationally. Which is a shame, really. I’ve read both Stein’s and Johnson’s platforms and both of them are willing to address the problems in the system. Johnson is the least realistic of the two and I like a lot of the Green Party platform.
More . . .