Are human beings still evolving in response to any recognizable factors?


#41

Yes, climate change can increase cold snaps because of [quote=“Lynn_Munter, post:39, topic:39113”]
I read it carefully and did not see where it said this. It said that deaths from heat would increase more than deaths from cold would decrease, but that’s not the same as saying there will be more deaths from heat than from cold.
[/quote]

Well, what do you think will happen?


#42

It’s hard to say what the worst aspect of climate change will be. I hardly think it will be storms, though. CC is happening right now, and will only become worse. And yes, CC can even exacerbate winter storms by disrupting ocean currents. I have experienced both the fury of Sandy and the more recent “Nor-easter parade.” Not fun!

btw, did you happen to read “Losing Earth?”


(Mark D.) #43

No, is that a novel?

Oh and I can’t think of what CC stands for. A little help?


(Phil) #44

Well, CCR is John Fogerty’s old band, but I think CC refers to climate change from the context.


#45

CC = climate change. Losing Earth Is an article. Do you want me to send you a link?


(Lynn Munter) #46

The number of deaths from heat will increase, but will they increase to 20 times the current level? Would changes in behavior mitigate some effects? Would even 20 times the current rate be enough to make our species evolve noticeably?

Like I said at first, I’d expect more effects from natural disasters, etc. Famine might select for smaller people who eat less or malaria resistance might move northward; a lot of things could happen.


(Phil) #47

All this talk makes me wonder if war has been a major evolutionary force in the last few thousand years. The young aggressive men go of to war and get killed, the more sedate stay back and farm and have children.
And we have a culture that is more docile and passive. Or do we?


#48

Not all get killed – the strongest become rulers with power to raise up more like them and keep the others down. But that is an interesting idea… I guess it depends which of the world’s cultures we’re looking at.


(Steve Schaffner) #49

Or else the local population with too few aggressive men is wiped out by the more aggressive group. (Note: this would be a form of group selection, which is at best controversial among evolutionary biologists.)


(Mark D.) #50

Got it. I was just reading it online when my wife found it inside today’s NY Times. Reading it now.


(Phil) #51

Interesting to consider. What adaptations led from a hunter gatherer culture to an agricultural society, to now largely an urban society? Does genetics have a role in those changes?


#52

Certainly.

  • Lactose tolerance (lactase persistence) in adults is one that arose in pastoralists.
  • An increase in the number of copies of the salivary amylase (AMY1) gene arose when humans domesticated cereal grains.

So now more humans could have milk on their Wheaties and easily digest it.


#53

Have you seen the movie “Soylent Green” or read the book? It’s the first ecological disaster movie I know of where climate change caused by green house gases makes the planet uninhabitable. And the move dates from 1973!


(Mark D.) #54

Oh yeah, in a theatre no less. Lets hope it doesn’t come to that.


#55

I think that people are people, and they can become more aggressive or more docile under circumstances not having much to do with evolution. The Lakota (Sioux) were corn farmers, but when they acquired the horse they aggressively expanded their territory, battling other Plains Indians, even successfully (for a time) defending it from white invaders. The transformation of the Comanches was even more dramatic (Read “Empire of the Summer Moon: Quanah Parker and the Rise and Fall of the Comanches, the Most Powerful Indian Tribe in American History” by S.G. Gwynne)

And it’s hard to believe, but there have been times in the history of Jerusalem when Christian, Jew, and Muslim lived together in peace. (Read “Jerusalem: the Biography” by Simon Montefiore)

So, blessed be the peacemakers, and [content removed by moderator] the politicians who fan the flames of hate, demonizing people groups, and inciting violence.

There is a genetic component to aggression, especially in animals. In the famous experiments involving domesticating foxes, Dmitry Belyayev was able to create a more docile variety, but he also created a more aggressive line.

Some species of animals are very close genetically, but in terms of aggression they could not be more different. Chimps are very aggressive, but their close relatives, the bonobos, want to “make love, not war.”

Horses and zebras are another example. They look similar, but are so very different in nature. The aggressive nature of the zebra has made it impossible to domesticate them. They might look docile in the zoo, but zoo keepers have to stay vigilant when working with them.


(Mark D.) #56

Seems like you agree with jpm that circumstances surrounding warfare could have the effect of culling or selecting for a propensity for aggressiveness. Of course it wouldn’t be as thorough going or fast as Belyayev’s focused work with foxes but given that warfare has been so prominent in human affairs for a good long time, we might collectively have received a similar effect?

When I think of the effects of warfare on our evolution it seems to me that one of the main capacities selected for might well be that of strategic planning. Anticipating what the enemy might do next and creating a plan in response seems to be something our species does more than most. If that is true I think we’d find the least aggressive people at the further extremes of where people are able to live. Makes me wonder about the lives of eskimos before contact with modern cultures. Perhaps living where surviving against the environment requires all of ones strategic efforts forces us to live more harmoniously and neighborly with one another.


(Lynn Munter) #57

Another cool aspect of the hypothesis of persistence hunting as a driver for human evolution is that it would encourage the development of not just running and shedding heat, but also tracking and visualization of what the antelope (or whatever you’re chasing) is going to do next, and how you might be able to cut it off. Which essentially means developing empathy, deductive reasoning, and the ability to envision events you can’t see.

I love how interesting this stuff all is. As far as warfare vs. peace, have you heard of the Moriori? They lived totally nonviolently on a remote island until the Maori came and wiped them all out.


#58

Not really. Except that males are genetically predisposed to aggression.

You are right about that! The Inuit (Eskimos) were the poorest people on earth, often facing starvation. Instead of fighting to resolve any differences that came up, they held a “song duel” in front of the village. If you could make your opponent look dumb but also make him laugh at himself, you win.


#59

btw, I’m not saying that all aggression is necessarily bad. I wouldn’t admire anybody who refused to defend his family or country.


(Mark D.) #60

Yep, by way of increased testosterone. It seems to be the active ingredient in modifying the base body plan which is female into a male.

I wonder if anyone else has read Fred Hapgood’s Why males exist: An inquiry into the evolution of sex. Not really a question whose answer is very surprising. By mixing genetic material we get variation and endless forms. But it was interesting to come across when it came out in 1979.