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Originally Posted by Burning Down
If you mean that people can possibly select the sex of their child due to things like the "test tube" baby or artificial insemination, then sure. But in regards to natural conception, there's no such thing as selecting the gender of the child. You get what you get.
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Sexual selection is roughly the same as assortative mating which means we don't pick our partners at random. We are attracted to some people and others .. not so much. We are selective when it comes to partner choice, the people we want to have children with. People we find attractive have qualities which typically makes them "fit", for example good mothers. You prefer a lady who has some boobs and tush to one which looks like a plank. Likely, boobs and ass is good if you want to give birth to and then raise a child. Attractiveness of the face (symmetry and so on) can be indicators of how fit people are in other traits, a sort of general quality indicator. Smell (sweat) is thought to give knowledge about the properties and quality of the person's immune system.
There's little basis for saying sexual selection plays a greater part now. At least I think so! If other selection pressures are higher, say food is sparse and there are more diseases (not saying that would be the case some tens of thousands of years ago, but), then finding a partner who is healthy and able could be arguably even more important.
Sexual selection is generally thought to have been extremely important in our evolutionary history. Some use it to explain why we are as kind and social as we are. The sex who has the most parental investment, the females, get to be choosy with the kind of males they want to have sex with. F.ex if you're gonna be pregnant for 9 months and then raise a baby after, you'd want a man who's loyal to you, kind and helps raise the child. Still, if it wasn't for this sexual pressure on men, it should make more sense from a selfish point of view to cheat as much as possible because as a man, you can potentually have children with very little investment. The investment is potentially as little as the sperm load you ejaculate and the energy spent courting and having sex.
So, some biologists believe a lot of our social aspects have evolved from sexual selection pressures on men from women. Some even hypothesize that women's gossiping is a way to exchange information about the quality of potential partners. "Have you heard? Lisa is so upset. She had an argument with Ben and he hit her!"
Needless to say, a statement that says sexual selection is more important now than before (when before?) is just a statement which is vague, non-specific and currently without support.
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Originally Posted by duga
It's a widely held belief amongst anthropologists. Granted, it is the type of thing that can't be proven, but it makes a lot of sense to me as well as people who study human development and evolution.
Edit: Just to expand a little bit, this theory is supported by fossil records. Without getting too technical, archeologists have found higher frequencies of hominid fossils in areas known to have been incredibly fertile and mild in climate at certain points in history. This means for a time those hominids were able to halt their nomadic nature and live off the fruits of the land. Does this prove that the result is self awareness? No, but what advantage does self awareness provide when it comes to basic survival? Not a whole lot. One of the only ways it would have come about is with the scenario I just described.
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That's well and fine, but it seems a little naive to me. The rough history of man I've heard is that we started walking on two which freed our hands which is important as we're tool users and we switched from a diet based on plants to a diet based on meat. You get a lot more energy per pound of meat and you don't need a huge stomach to digest enough to keep you going. You also don't have to spend most your day foraging and then resting as you digest, something other plant diet apes have to.
Basically, we switched to a source of nutrition which allowed our brains to grow big and we had our hands free and we also got a lot of free time on our hands. When you don't have to spend all day getting food, you can spend it developing culture.
The people you talk about who lived in locations of plenty, I'm not sure what species of man you're talking about, but if they had a culture (could switch off being nomadic and choose to settle), then I'm thinking they were probably already self-aware and had been for a long time.
Even Coco was self-aware!
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Originally Posted by Neapolitan
If plants and animals evolve in response to the changes in the biosphere; like a change in climate, maybe an introduction or disappearance of flora and fauna that would totally alter their way of life, thus creating a change of their position in the food change or eating habits, like evolving to elude beig eaten, or evolve to be harder, better, faster, stronger plant and/or animal etc. So if plants and animals evolve because they have to adapt, human don't have to the changing world around them humans can alter the habitat they live and create tools, instead of adapting on the genetic level like plants and animals, so why would they have to evolve - it would be a mute point.
Cheetas are lean mean hunting machines, they evolve to run fast, and take out their prey, on the other hand human don't have to evolve for speed they can just create say a bow and arrow right to hunt and kill, right? That would deminish the need to evolve into a fast running species or some subspecies of super fast humans who can chase after prey, while the rest of the species would live a more sedentary lifestyle as like being hunter/gathers or into some kind of husbandry.
Some scientist once siad that the human race could not survive as a species if it wasn't for their intellect. He point out that humans aren't the fastest, or the strongest, and without the domiciles they know how to build, and the clothes they know how to make, the human species would not be suitable to live all over the world like they actually do.
So in short it's human's intelligence that stops us as humans from evolving.
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You should read my post on the previous page. I wrote a set of criterias which have to be fulfilled for there to be no evolution.
A quick comment still, you think we don't have to evolve in the same "arms race" as the fish we eat and the chickens we kill. This is true, we don't. But how about the viruses, bacteria and range of parasites that still infect us on a daily basis? We're talking here about organisms and evolutionary particles which have a very short generation time which means they evolve incredibly fast in this arms race against us.
We don't stop evolving. You seem to think it's something animals do because they "need" to. They don't, it's a consequence. I keep saying it is, but I'm not sure people get what it entails. Basically, it's not something we choose to do. It's not something we can turn off. Evolution will continue to happen as a consequence unless we can turn off the causes. If life as it is was constant and could not vary, not even mutate, from generation to generation, then there would be no evolution. However, hereditary variability is an integral capacity of life as it is and evolution comes with it. It can be slow, it can be fast, but the main point is it's happening.