Questions about human evolution

[Elfboy]

first off, I'd like to start by saying I find human evolution fascinating and think it is probably true, but there are some aspects of it that just do not make sense to me.
- why are our feet so deformed and weak? why don't we have any kind of protective padding like other primates or wolves?
- why are our bodies so frail? compared to other predators like tigers, bears etc, human beings have relatively little ability to sustain major injuries.
- why are humans so weak psychologically? the average human being is so psychologically fragile it is pathetic. people are generally fearful of conflict and have a very difficult time finding psychological balance, overcoming psychological distress and staying strong in the face of conflict.
- where are all of our instincts? sure, humans are intelligent and quick learners, but if you threw most people out into the wilderness and they had to survive, most of them would die without years of training and study of various plants and hunting techniques
- why is killing so unnatural for us? sure, humans in the past have done it a lot, but it seems we need to be pushed to unnatural limits to do so. how would someone like an INFP or enneagram 4 survive in a world where killing to survive was a necessity?

 

[UniqueMixture]

A lot of the answers to your questions require not thinking about evolution on just the individual level. All creatures evolve collectively and individually. Human social culture of various members of a community optimized for different tasks allows for and even "requires" various weaknesses because non-optimized tasks for the individual are supposed to be picked up by various members of the community. For example, take the "gay" gene as an instance. It may not make sense from an individual point of view how such a gene could propagate itself, but from an evolutionary standpoint gay members of a community generate resources for a community without those resources being consumed by the children of the individual. This creates surplus resources for the other members of the community.

 

[ygolo]

- why are our feet so deformed and weak? why don't we have any kind of protective padding like other primates or wolves?

I'm not sure what you mean by deformed and weak. Our feet our perfectly capable of supporting our weight.

As for padding, our feet can become calloused. When I was a kid, I use to run around barefoot all the time. No issues. My parents did the same thing.

It may not be as strong a padding as other animals, but we didn't really need it.

Anything that is not needed is using energy, and in the past where food was hard to come by, that would mean that there would be evolutionary pressure to get rid of it over the generations.

- why are our bodies so frail? compared to other predators like tigers, bears etc, human beings have relatively little ability to sustain major injuries.

Fragile in what respect? People heal from cuts, lesions, fractures and broken bones. We can survive even with broken bones and lost limbs.

Again, sturdier bodies require energy--energy better suited to fulfill the human evolutionary niche...thinking in order to survive.

- why are humans so weak psychologically? the average human being is so psychologically fragile it is pathetic. people are generally fearful of conflict and have a very difficult time finding psychological balance, overcoming psychological distress and staying strong in the face of conflict.

Humans are social animals. Thus our psychology reflects that of being one. We can 't really tell how dogs or other mammals feel, but I've heard of gorillas, dogs, and even pandas becoming depressed at the loss of a mate or master.

- where are all of our instincts? sure, humans are intelligent and quick learners, but if you threw most people out into the wilderness and they had to survive, most of them would die without years of training and study of various plants and hunting techniques

As we learn more about instincts, we are finding even many bird migration patterns are essentially imprinted in them from the previous generation.

- why is killing so unnatural for us? sure, humans in the past have done it a lot, but it seems we need to be pushed to unnatural limits to do so. how would someone like an INFP or enneagram 4 survive in a world where killing to survive was a necessity?

I don't think we have a problem killing plants and animals for food. Killing each other to survive is not necessarily a good thing for the species, especially for social animals.

Like UniqueMixture said, evolution is something that happens with populations over generations. Although the details need to be worked out, there isn't anything I know of that makes human evolution a dubious theory.

 

[Owlesque]

I did my undergrad in biological anthropology and zoology, but it was focused mostly on osteology so I won't comment on the instinctual/psychological questions...

The physical attributes are more a lack of evolutionary pressure - early humans (of our own species, not just distant members of the same genus) had bones that were distinctly more robust than modern humans' because they undoubtedly lived much more strenuous lives and couldn't afford to have the lighter skeletons of their more sedentary descendants (though even many of these robust specimens are riddled with healed fractures - humans as a whole are simply more gracile as energy consumption shifted towards increased brain size). Increased strain on the skeleton from extensive muscle also use triggers bone growth and strengthening much like soft tissue forms callous, so it's probably a combination of evolutionary and environmental pressure (think of it as a lack of pressure for robustness rather than positive pressure for gracility) that has resulted in our slender skeletons.

The condition of our feet is further complicated by the fact that humans have only been bipedal for a short while, at least in terms of evolutionary time. We (for the most part) wear shoes, live fairly sedentary lives, and have removed ourselves from an environment where selective pressure can act on the strength of our bodies - an exceptionally robust individual is probably not any more likely to have children or live longer than a frail individual (assuming their stature is not the result of environmental factors such as diet/disease/etc) so genes from either are equally likely to be passed on.

 

[UniqueMixture]

I dispute the last part, because athleticism and beauty play some role in mate selection.

 

[Owlesque]

I dispute the last part, because athleticism and beauty play some role in mate selection.

Yes, but beauty is highly variable, subjective, and not necessarily correlated with skeleton robusticity, and environmental changes in phenotype as brought about by physical activity/working out/etc. cannot be inherited so can't be acted on evolutionarily.

 

[UniqueMixture]

Yes, but beauty is highly variable, subjective, and not necessarily correlated with skeleton robusticity, and environmental changes in phenotype as brought about by physical activity/working out/etc. cannot be inherited so can't be acted on evolutionarily.

Wrong, there is growing evidence that behavior has an effect on gene expression. So phenotype can be an indicator of genotype. There is a field devoted to it called epigenetics.

Edit:

While the changes may not heritable they can work as "social proof" that the underlying genetic structure is robust.

 

[Randomnity]

first off, I'd like to start by saying I find human evolution fascinating and think it is probably true, but there are some aspects of it that just do not make sense to me.
- why are our feet so deformed and weak? why don't we have any kind of protective padding like other primates or wolves?
- why are our bodies so frail? compared to other predators like tigers, bears etc, human beings have relatively little ability to sustain major injuries.
- why are humans so weak psychologically? the average human being is so psychologically fragile it is pathetic. people are generally fearful of conflict and have a very difficult time finding psychological balance, overcoming psychological distress and staying strong in the face of conflict.
- where are all of our instincts? sure, humans are intelligent and quick learners, but if you threw most people out into the wilderness and they had to survive, most of them would die without years of training and study of various plants and hunting techniques
- why is killing so unnatural for us? sure, humans in the past have done it a lot, but it seems we need to be pushed to unnatural limits to do so. how would someone like an INFP or enneagram 4 survive in a world where killing to survive was a necessity?

Evolution doesn't really work like that. It works by having the "best" (=most-transmitted to offspring) random mutations survive. It isn't a process of developing some kind of optimized animal. It's actually a really chaotic process that only really makes sense on a large scale, since there is quite a lot of random chance involved.

The answer to most of your questions is intelligence - developing culture, tools and traditions allowed us to survive without the keenly developed instincts/teeth and claws that some animals have. These social features are also probably why things like aversion to killing (at least within your own group) and "psychological fragility" etc are a fairly common human trait - but consider the millions of people who have been slaughtered by other people in the past, which is no doubt still occurring at this moment all over the world. I wouldn't really say that humans are averse to killing.

Another thing is that society may evolve by a loose definition of the word, but not in a biological sense, since beliefs are not genetic - so changes in cultural beliefs etc are not really going to follow the same evolutionary rules.

 

[UniqueMixture]

I wonder if beliefs can be correlated to genes

http://lohdown.caltech.edu/script_archive?date_to_view=2008-09-11

 

[Randomnity]

I should have said "not completely genetic". Pretty much anything about human behaviour is likely to be part genetics and part environment, including upbringing. But the environment factor means it won't follow the same pattern of evolution that something strictly genetic would.

 

[INTP]

first off, I'd like to start by saying I find human evolution fascinating and think it is probably true, but there are some aspects of it that just do not make sense to me.
- why are our feet so deformed and weak? why don't we have any kind of protective padding like other primates or wolves?

they arent deformed and they are weak because our current form of footwear doesent really suit us.

i read this funny blog post of a barefoot runner a while ago. he had been teased a lot that some day he will step on a piece of glass and get hurt. well, the blog post was about this, he found a piece of glass on his feet, it had been there for few days, he knew this because it had started to grow new skin on it before he noticed it . you say no padding?

- why are our bodies so frail? compared to other predators like tigers, bears etc, human beings have relatively little ability to sustain major injuries.

i dont think this is true, humans have really good ability to survive from major injuries, much better than many other animals. if all human were large as bears, we wouldnt had survived till today very well, because our strengths are in areas which require us to for example outrun deers, horses etc.(even tho they run faster, humans are capable of chasing them till they collapse, its an old form of hunting) and walk across deserts etc.

- why are humans so weak psychologically? the average human being is so psychologically fragile it is pathetic. people are generally fearful of conflict and have a very difficult time finding psychological balance, overcoming psychological distress and staying strong in the face of conflict.

we live in environment that is unnatural to us, this creates psychological problems to humans and other animals.

- where are all of our instincts? sure, humans are intelligent and quick learners, but if you threw most people out into the wilderness and they had to survive, most of them would die without years of training and study of various plants and hunting techniques

again we live in environment that suppresses our natural instincts, if you go live in a jungle for few years, you will notice those instincts coming back. ever wonder why small children doesent want to eat green vegetables? its because of evolution, it has been beneficial for small children to not eat green plants, because they may be poisonous. sex, graving for sweet and fatty foods etc etc are because of our instincts, they havent gone anywhere, its just that things like intuitively understanding our environment isnt enforced much by our environment. most genes need environment for them to be triggered, since we live in unnatural environment, we lack a lot of our instincts also, but those can be triggered by changing the environment.

- why is killing so unnatural for us? sure, humans in the past have done it a lot, but it seems we need to be pushed to unnatural limits to do so. how would someone like an INFP or enneagram 4 survive in a world where killing to survive was a necessity?

society says that killing is wrong. INFPs and e4's are just as capable of that as others, its just that they have structured their Fi values according to the environment they live in. im quite sure that if you would put my INFP friend in a forest alone and telling him that he needs to survive, he would just die right away. but if they had been living in some jungle tribe, im pretty sure that they would survive just fine.

 

[Fluffywolf]

Don't have much time to read the enitre thread but here are my thoughts.


- why are our feet so deformed and weak? why don't we have any kind of protective padding like other primates or wolves?
Try walking around a few miles a day on bare feet, the padding will grow on it all by itself!

- why are our bodies so frail? compared to other predators like tigers, bears etc, human beings have relatively little ability to sustain major injuries.
Before we were hunter-gatherers, we probably lived in trees and ate fruit. And while hunter=gatherers, we used weapons and traps. Not much risk for injury. Point is, we've never been the kind of animal that needs to throws himself in the midst of danger to get a kill. Doesn't mean we've not done that in history, but that was not as a means to survive, but as a means to conquer.

- why are humans so weak psychologically? the average human being is so psychologically fragile it is pathetic. people are generally fearful of conflict and have a very difficult time finding psychological balance, overcoming psychological distress and staying strong in the face of conflict.
We're not psychologically weak, we're psychologically complex. It makes us better, not worse.

- where are all of our instincts? sure, humans are intelligent and quick learners, but if you threw most people out into the wilderness and they had to survive, most of them would die without years of training and study of various plants and hunting techniques
We've survived through tradition for a very long time. Why use instincts if you can be taught something better?

- why is killing so unnatural for us? sure, humans in the past have done it a lot, but it seems we need to be pushed to unnatural limits to do so. how would someone like an INFP or enneagram 4 survive in a world where killing to survive was a necessity?
If only this was true. Apart from just needing to have a survival instinct to kill, humans can have tons of reasons to kill. In fact, plenty don't even need a reason at all!. *sniff* INFP E4 will kill too if he or she is hungry and wants to roast a rabbit.