Evolutionary rollercoaster

[Rokcet Scientist]

I think it is good to to remind ourselves of the concept of the speed of evolution. To put it into perspective. Because when we look at homo, for instance, which took about 6/7 million years to develop from a proto-ape (our common ancestor with chimps) to homo sapiens sapiens today, uncomfortably many are lulled into the conclusion that evolution, because it took such a long time, is tediously slow. And that it takes millions of years.

Locusts, however, (as an example) can considerably evolve in a matter of mere weeks!

Swarming 'swells' locusts' brains

Swarming locusts not only look different and act differently to solitary locusts, they also have much larger brains.

This is according to scientists at the University of Cambridge who captured images of the results of dramatic changes inside the insects' heads.
The team described how the same locust could switch between a "solitary" and "gregarious" (swarming) phase.

They described their findings in Proceedings of the Royal Society B.

"Normally locusts would avoid close contact with each other," explained Dr Swidbert Ott of the UK's University of Cambridge. "It's only when they are forced to be in close contact that they change dramatically."

This is a survival mechanism. It occurs when the insects [...]

http://news.bbc.co.uk/2/hi/science_and_ ... 158856.stm

It's consequently that I prefer to think of evolution as a process that unfolds in fits and starts. Sudden, short, but 'high-energy' bursts of great evolutionary change, interspersed with looong periods of near evolutionary inertia.

We ourselves illustrate that pretty dramatically, imo: we know that 3rd millennium BC Egyptian male adults were about 5 feet in length. Medieval western Europeans, 4 millennia later, were still around 5 feet tall. However, in little more than the past century, only 100 years!, western Europeans have grown an average of 8 inches...!
As always, the evidence is right in front of our eyes.

[Digit]

It's consequently that I prefer to think of evolution as a process that unfolds in fits and starts.

It's called 'punctuated equilibrium' RS and is one of the reasons that genetic mutations are seen as a vehicle of evolution.

Roy.

[Minimalist]

"western Europeans have grown an average of 8 inches.."



But is that "evolution" or just better nutrition?

[Johnny]

"western Europeans have grown an average of 8 inches.."

But is that "evolution" or just better nutrition?

Right now it's likely just better nutrition but it'll probably end up as both after the same environmental factor has been repeated for several more generations. If resource availability and nutrition was a factor in our past evolution, it's just as much a factor today. Being capable of retrieving extra insect protein with a stick improved the diet of proto-apes and must've resulted in population growth and then refinement of protein acquisition tools as numbers stretched resources.

Unfortunately, I think we've altered the rules of natural selection sufficiently for our species that our biological evolution has been arrested severely and our technological evolution will dramatically outpace our strictly biological from here on.

[Digit]

Interest view there Johnny, but there was an article posted here some time ago that reported that human evolution was accelerating!
No explanation was suggested and left me wondering thus....
the basic stock becomes separated by large distances, different climates etc, adaptions will take place ala Darwin, but what happens if those separate groups then regain contact?

Roy.

[dannan14]

the basic stock becomes separated by large distances, different climates etc, adaptions will take place ala Darwin, but what happens if those separate groups then regain contact?

Roy.

Seems to me that creates slow, steady evolution. An alternative to all the changes happening in one small population which then spreads around the world. i think it just about sums up the difference between OOA and MR

[Digit]

And that I suspect is what is happening today.

Roy.

[Johnny]

Interest view there Johnny, but there was an article posted here some time ago that reported that human evolution was accelerating!
No explanation was suggested and left me wondering thus....
the basic stock becomes separated by large distances, different climates etc, adaptions will take place ala Darwin, but what happens if those separate groups then regain contact?

I'd really be curious to know what direction that accelerated evolution is heading and what its purported catalysts are. Perhaps we are influencing our environment and biology enough to outstrip the evolutional slowdown caused by longer lifespans and increased generational gaps as more young adults are having children later in life. I'm still skeptical, though. I mean, when was the last time you saw a dude get eaten by a lion on the savannah? Natural selection, at least, is dead for our species. We selected against it.

[Digit]

NS is dead by the manner that you suggest Johnny, therefore more genetic variations should survive and produce offspring as the filtering mechanism that thinned our variabilty for many years is over.
I have just been watching a programme about a young woman who died circa 1850 in London.
19? yrs old, 4ft 7 tall riddled with syphylis and had had rickets as a child.
She probably didn't live long enough to contribute to a gene pool.

Roy.

[uniface]

Natural selection, at least, is dead for our species. We selected against it.

Yes. But also no.

The attraction of men to physically desirable women, and of women to wealthy/high-status men is inextinguishable. But the net effect of usury finance is to favor the survival and flourishing of those at the top of the financial pecking order, leaving those at the bottom to fend for themselves as best they can. The lack of even rudimentary health care today, as during the last great depression, is ravaging the gene pool in the long run.

Which is, to my way of looking at things, the de facto imposition of un-natural selection.

[Johnny]

Which is, to my way of looking at things, the de facto imposition of un-natural selection.

That's it exactly. Unnatural selection. It's just almost eugenics.

[Minimalist]

Unfortunately, I think we've altered the rules of natural selection sufficiently for our species that our biological evolution has been arrested severely and our technological evolution will dramatically outpace our strictly biological from here on.

I agree. Human "culture" interferes with natural selection. I think it goes back to HE.

[Rokcet Scientist]

Unfortunately, I think we've altered the rules of natural selection sufficiently for our species that our biological evolution has been arrested severely and our technological evolution will dramatically outpace our strictly biological from here on.

I agree. Human "culture" interferes with natural selection. I think it goes back to HE.

, Min!

Natural selection, at least, is dead for our species. We selected against it.

Come on! You don't fool nature so easily. You can't dick around with the forces of nature. Mother Nature has an entire toolkit to deal with our 'interference', to keep evolution going anyway: disease, drought, famine, natural disasters, etc. etc. "Tests of Man", or 'Scourges', in biblical verbiage.
Take cancer: in medieval Europe cancer wasn't a problem. There wasn't any. Very few people died of cancer (because the great majority simply never got old enough to develop it...).
I hazard a wild guess that it wasn't much different elsewhere?
Today we, on average, get to be 80. And we also have lots of cancers! And scores of other diseases that simply didn't exist in the Middle Ages.
And every now and then, say twice per millennium, we get a major epidemic – a.k.a. a pandemic – to drastically cull the weak, the unfit...
And, statistically, we are waaaay overdue for one!

I.o.w.: plenty of evolution from where I sit, Johnny. Despite homo's interference. And sometimes even because of it.

[Rokcet Scientist]

'punctuated equilibrium'

"We go from very simple pre-Cambrian life-forms to something as complex as a cephalopod in the geological blink of an eye, which illustrates just how quickly evolution can produce complexity," said Mr Smith.

http://news.bbc.co.uk/2/hi/science_and_ ... 173293.stm

[Digit]

Which, again of course, supports Darwin RS, till the circumstances in which an organism fits changes there is no pressure on that organism to change. Changing too slowly could well lead to extinction.
Fortune favours the fast!

Roy.