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Humans have, in a relatively short amount of time, evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel.

Meanwhile, a lion is still a lion and a beetle is still a beetle.

Is there a specific reason for this? Do we have a particular part of brain that no other animal has?

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I don't understand your last question; evolution is largely directed by genetics, a modified organ doesn't pass itself along (just as amputees don't have limbless children). –  Nick T Jan 24 '12 at 0:40
    
-1 for starting with "it seems to me". Can we try and be a bit more quantitative (or at least back up your observations)? –  Poshpaws Jan 25 '12 at 21:14
    
@Poshpaws--"it seems to me" has been removed. Thanks for leaving the comment. –  Matthew Patrick Cashatt Jan 25 '12 at 22:00
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en.wikipedia.org/wiki/Bifurcation_theory, think of genetics as the parameters, nukes, computers, and space travel as variables. There's no reason to believe we're evolving "faster" in a genetic sense. –  Shep Sep 13 '12 at 8:22
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on a genetic level we have evolved at the same rate, but we have evolved differently - we have evolved the ability think and act intelligently, communicate information, and learn from our peers far better than any other animal. So much of what we know is learned rather than innate - we did not evolve the ability to make a nuke rather we evolved the ability to learn and teach how to make one etc. Take away the evolved ability to learn and communicate knowledge and we wouldn't be all that different from an ape. –  GriffinEvo Feb 26 '13 at 12:25

8 Answers 8

up vote 21 down vote accepted

We have the Human Accelerated Regions (HARs) which are some of the most rapidly evolving RNA genes elements. While heavily conserved in vertebrates, they go haywire in humans and are linked with neurodevelopment.

Thanks to @Nico, the following paper compares the human genome with that of the chimp and identifies genetic regions that show accelerated evolution. The most extreme, HAR1 is expressed mainly in Cajal-Retzius neuron cells which hints at its important role in human development.

Pollard KS, Salama SR, Lambert N, Lambot M-A, Coppens S, Pedersen JS, Katzman S, King B, Onodera C, Siepel A, et al.. 2006. An RNA gene expressed during cortical development evolved rapidly in humans. Nature 443: 167–72.

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Would be better to link to some original papers like: An RNA gene expressed during cortical development evolved rapidly in humans. –  nico Jan 23 '12 at 9:58
    
Many thanks for the reference –  bobthejoe Jan 23 '12 at 9:59
    
Thanks bobthejoe! –  Matthew Patrick Cashatt Jan 23 '12 at 13:52
    
thanks +1 I wonder about this my self. –  Jim Thio May 24 '12 at 9:23

Interesting and thought provoking. Though I am curious why you wouldn't think plants and animals are conscious. Maybe they aren't self aware like you are, but if a lioness preserves herself to tend her cubs, is she not aware of the fact that things can exist or no longer exist? That life can be lost? No matter at what level you may perceive, this realization in her will trigger an emotion ( chemical reaction) which in turn will give her the fortitude to continue to survive, or as we sometimes see in nature, to not. How are we different? I hate this cut off that I see. " if it doesn't do it on the level that we do it then it don't do it at all". That's silly, if you believe in an evolutionary development of genetic material how can you not believe that emotions and awareness have levels of development too? Sounds a bit like the "chosen one" complex. Once you take that road, you're a hop skip and a jump from the creationist and 6000 year old earth.

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I think you misunderstood the question--and made several assumptions about my way of thinking at that. The question isn't about consciousness. It is about evolution. A lioness may preserve her cubs to the best of her ability--in the same way as it has been done for a few hundred thousand years, and yet a lion may still come along and eat them. Not once in the course of evolution has it occurred to the lioness to develop, say, rule of law to prevent this. I simply want to know why. I am about the farthest thing from a creationist, by the way--I am asking a question about evolution. –  Matthew Patrick Cashatt Nov 26 '13 at 15:20

What you are talking about is genetic vs memetic evolution. While both are important in our species, the memetic evolution is responsible for the changes you are citing (mostly technological advancements and "culture"). There are some interesting situations where memetic evolution is actually "cancelling out" genetic evolution. For example medical technology has largely allowed many (at least in the developed world) to survive in spite of genetic handicaps (lack of resistance to a pathogen, insulin, glasses, etc). Despite this I would argue we are still evolving rapidly in the genetic sense though not for the reasons you imply. In most vertebrates (any slow-reproducing creature), there is an ongoing selective pressure against pathogens. If their immune systems don't continually change (and antibiotics don't intervene), pathogens will wipe them out. While not as glorious as developing bipedalism, this is still evolution. We are also now a very transient species with people migrating extensively compared to the recent past. This leads to new genetic combinations and thus potential selection. It could be argued (as others have) that the selective pressures for brain development (especially for language ala the FoxP2 gene) have brought about the rise of language, technology and culture. However I would argue that these evolutionary changes largely occurred, at minimum, the last few tens of thousands of years. As others have also noted, crazy genius isn't THE end goal of evolution, it is merely ONE possible outcome. The real goal is genetic perpetuation (which we do seem to excel at) ;)

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Many animals have actually reached an optimal solution to their evolutionary path. That means that from where their genome is right now, pretty much all changes are harmful to expected reproduction. Over time such species start to have less variability within their genome and start to evolve less. Evolving is simply not sensible anymore.

Humans on the other hand are in an extremely open evolutionary path, that means there is much variability within the human genome that leads to greatly varied expected reproduction.

That is why humans are evolving so fast.

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Very interesting!! –  Matthew Patrick Cashatt Sep 13 '12 at 20:32

The ability to walk on two legs was hugely significant in human evolutionary development. This led to the hands being freed up to develop into precision tools rather than having to be durable for walking on rough terrain. Increased dexterity in the hands led in part to the leap forward in human development.

~ The Human Body (Prof. Robert Winston - BBC Documentary 1998 (BBC Text Summary)

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This is from a documentary I recently watched, I'll find some proper references when I get back in :) –  Rory M Jan 23 '12 at 8:56
    
Was that the one that also talked about our jaw muscles being weaker, thus allowing our brain to grow more? –  Brightblades Jan 23 '12 at 13:03
    
Thank you Rory M! –  Matthew Patrick Cashatt Jan 23 '12 at 13:52
    
@Brightblades I don't recall it mentioning that, it was a fairly recent BBC offering? –  Rory M Jan 23 '12 at 18:13
    
@Brightblades apparently not as recent as I thought, I've added the reference =) –  Rory M Jan 25 '12 at 22:25

It seems to me that humans have, in a relatively short amount of time evolved from apes on the African plains to upright brainiacs with nukes, computers, and space travel.

The question covers changes of two sorts: biological evolution and cultural evolution. The other answers speak to biological evolution, but I want to point out that much of the most striking changes ("nukes, computers...") are due to the evolution of our culture.

By 40,000 years ago most of our biological evolution to the present had happened (perhaps the most notable exception being changes related to our coevolution with disease organisms). Yet although we had achieved upright brainiac-hood by the apparent evidence, we were not strikingly different from other large animals.

We had sharpened rocks and sticks, and made better use of the surroundings, particularly in non-food categories, than other animals. We had been successful enough to spread throughout much of the old world. Nevertheless, the overall contrast with other animals seems rather muted when viewed by the differences with the modern world.

Most of the visible changes since then are due to evolution happening outside our genes and bodies in what can be called culture. Other animals have culture but our nature gives us many times the cultural capability. We build upon the culture we find ourselves in and make it more effective. The cultural presevation and advances come not just from aping ('monkey see, monkey do'), but from language, and from mechanisms of cultural distribution and preservation, most notably from the invention of written language. These things have driven the cultural evolution of the largest visible changes, those of the last few millenia.

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Very interesting! And don't forget memes that use our social interaction as a vector for survival, evolution and preservation. –  Matthew Patrick Cashatt Jan 24 '12 at 1:24

This question appears to address at least two distinct concepts:

  1. the "speed" of evolution
  2. whether there is some "end goal" that evolution seeks

I will provide an explanation of each separately below:

The Speed of Evolution

The speed at which a species evolves—that is, the speed at which it acquires new heritable characteristics—can be affected by numerous factors. Among the most obvious which come to mind are:

  • existing population size
  • reproductive cycle rate
  • number of offspring
  • offspring survival rate
  • environmental demands

That said, have humans evolved faster than other species?

On the whole, I do not feel that I could say without a doubt that humans have evolved significantly faster than other organisms. Considering the above factors (we have a slow reproductive cycle, few offspring, etc.), it seems unlikely but this is where a zoologist would know better. The answer provided by bobthejoe may provide insight as well.

I would just raise a word of caution before leaping to the conclusion that we have evolved rapidly without looking into it, because while we often study human evolution quite extensively in biology classes and thus are more aware of changes like upright walking and opposable thumbs and increased brain size, that doesn't mean other animals didn't evolve that much as well (we just don't learn about them in as much detail). Being a psychologist and not a zoologist, I do not have the knowledge to say with any surety that other species did not evolve in their own ways to the same magnitude as we have in the last 3-4 million years, so perhaps someone else can help you there.

But you ask whether we have a particular part of our brain that no other animal has; the answer to this is no, but the parts of our brains which we do share with animals are often much larger than as seen in those other species.

The "Goal" of evolution

I would like to point out here that human technology has nothing to do with evolution. Not only have all of our notable technological achievements occurred in the last couple hundreds years when human evolution was at its slowest (early human evolution as we know it today dates back at least 5-7 million years, and it was during this several million year period when all the genetic evolution you speak of happened), I would argue that human spaceships and computers are no more sophisticated to us than a mushroom garden and ventilation system are to a termite. I could be wrong here but it seems as if you are under the impression that evolution is striving towards something... That humans are somehow intrinsically better than lions or sharks or beetles. On the contrary, each of these creatures is not significantly more or less adapted to their environments as we are to our own, and in many ways these creatures possess features which are beyond our own.

I shall leave you with one of my favorite quotes:

"We need a wiser and perhaps a more mystical concept of animals. We patronize them for their incompleteness, for their tragic fate having taken form so far below ourselves. And therein we err, and greatly err. For the animal shall not be measured by man. In a world older and more complete than ours, they move finished and complete, gifted with extensions of the senses we have lost or never attained, living by voices we shall never hear. They are not brethren, they are not underlings. They are other nations caught with ourselves in the net of life and time, fellow prisoners of the splendor and travail of the earth."

–Henry Beston, in The Outermost House

I don't have a dog in this fight, and I could very well be falsely assuming that you think this particular way when you in fact don't (you only wrote 4 lines after all, it's hard to glean much from that), but I wanted to make sure that these concepts were clear either way, particularly for any future visitors who might get the wrong impression. :)

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@MatthewPatrickCashatt it seems like you're coming at it from a fairly anthropocentric view which stoicfury is trying to address –  Nick T Jan 24 '12 at 0:39
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@MatthewPatrickCashatt: Just because your question is posed with few words does not mean it is "simple". Evolutionary biology is a vast and complex field which you—based on your question and subsequent responses—appear to grossly under-appreciate. With all due respect, I think you misinterpreted my answer as a personal affront and typecast the entire response as nonsense when in fact it is quite relevant. :\ Based on your personality profile it is unlikely you will change your (public) position on this though, even if you were to (secretly) agree with it after rereading it more fairly. –  stoicfury Jan 25 '12 at 18:39
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Just to be clear though, you write in your comment above "There was no assumption or innuendo in my question." This is false. The question "Why have humans evolved much more quickly than other animals?" assumes at least 2 things: that humans have evolved and that humans have done so faster than other animals. The context of your question suggests you think of evolution as a linear progression towards an "advanced state"; as if there is a "beginning" and "end" of evolution. This, as any biologist will point out to you, is false. That's all I was attempting to clarify. :) –  stoicfury Jan 25 '12 at 19:16
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"The reason for the down-vote was that a great answer existed already and, judging by the up-votes garnered by that answer, it seems validated." Downvotes are for answers which are not useful, i.e. irrelevant or false. If SE downvoting was designed the way you suggest, it would not make sense to be able to upvote more than 1 answer. In other words, while you can have only 1 accepted answer, there can be more than 1 useful answer, and in fact there are badges for when "merely useful" answers outscore accepted answers, to highlight the fact that the first is not always the best. :) –  stoicfury Jan 26 '12 at 0:23
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I wish I could give this answer a hundred +1 votes! I find myself in 100% agreement with stoicfury on every point. Well done sir! Bravo. –  Brightblades Jan 26 '12 at 12:38

I believe that it is significant that we spend so much of our brain-power on deciding who we want to mate with. For lions it seems like choosing a partner is much less based on rational thinking. The weakness of this theory is that I do not know how humans behaved earlier, and whether mating was strictly regulated by cultural rules to ensure that mating was not based upon convenience, but rational thinking about what who is the best partner in the long-term.

The reason for me believing that this is so important, is that a well-functioning couple in a well-functioning community, will have the time and energy to educate their children, who again will make wiser decisions on who they will choose as their partner.

I would love to get this theory tested (and hopefully rejected, as that is the way I learn the most) by this community.

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I really doubt if most people make their mating decisions based on rational thinking. But indeed, sexual selection may played important role in evolution of human brain. Anyway, I think answers should be based on facts rather than personal opinions. –  Marta Cz-C Jan 25 '12 at 22:36

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