Horizon - Have Humans Stopped Evolving?
- Thread starter mosaix
- Start date
I think I remember hearing about (on a different programme, ages ago) a branch of hominids that almost evolved away from mainstream mankind. They were in an isolated area of South Africa, I think, and began to communicate in a language consisting of bird-like whistles and tweets.
It's weird to think of another type of human, like neanderthals, living alongside us.
It's weird to think of another type of human, like neanderthals, living alongside us.
They are triatomine bugs, immigrating into "domestic and peridomestic environments" ( the huts and goat pens of the poor) in South America. I can't tell you which particular species this was observed in, but if it is important I have one of the world's experts available within a few days, and he'll talk your ear off for hours – days – weeks on his favourite subject (he's been doing it to me for several decades, and still not run dry.
J Riff
The Ants are my friends..
Baseball players use whistling to pass signs back n forth, and generally earn a lot more than highly intellectual writers. )
Chris
Not important, but I have been involved on occasion with arguing with creationists. One of their arguments is that no-one has ever seen evolution operating. They are wrong, and I have one or two references to show that, but it is always nice to have more. Is that study available on line?
Not important, but I have been involved on occasion with arguing with creationists. One of their arguments is that no-one has ever seen evolution operating. They are wrong, and I have one or two references to show that, but it is always nice to have more. Is that study available on line?
Starbeast
Benevolent Galaxy Being
Humans are still evolving, we haven't been around that long. Even the dinosaurs would have continued to evolve had they they not suddenly ceased to be, some of the species were growing larger brains. Anyone see the model of the dinosaur humanoid.
J Riff
The Ants are my friends..
That's-s-ss-s S-s-sssCary
Okay I see the problem now:
You are all discussing natural selection. Changes in height are largely a result of better diet and vitamins, especially during childhood. But certainly there must be slight changes in human populations over time.
This is why I think that program must have been confused. People are discussing different things. If the question is just 'has natural selection on the human population stopped' then I agree with all the comments made. In the developed world, then probably yes; in the developing world, then certainly not. Just look at sickle cell anaemia as an example if you want one.
Chris, were these triatomine bugs a new species? Could they no longer reproduce with the original population of bugs? Because if not, they have not 'evolved'. If so, then I will unreservedly withdraw my quote, but until then the Creationists have one thing right "that no-one has ever seen evolution operating." Though that is a quite nonsensical argument given that our life-span is only 60-100 years long.
Look at how many breeds of domestic dogs there are. Thousands if not tens of thousands. Some breeds are centuries old. However, breed some mongrels together over several generations and you still get something close to an original dog. It is getting close though, when a Pekinese can no longer mate with a Great Dane then you would have a reproductive barrier.
Evolution needs two things:
1) Environmental stress that favours survival of the fittest by natural selection.
2) A isolating mechanism between populations, either ecological, reproductive or genetic.
Since we are essentially one single population there is no isolating barrier. QED Evolution has stopped.
If we ever colonised space and other planets then an ecological barrier would be the physical barrier of travel between worlds. A reproductive barrier would be a 'Larry Niven' Jinxian human trying to mate with a Crashlander human. A Genetic barrier would be the impossibility (despite Star Trek) of a human mating with a Klingon.
I'm still sticking to this because unless things have changed, my definition of evolution is "the sequence of events involved in the evolutionary development of a species or taxonomic group of organisms."
You are all discussing natural selection. Changes in height are largely a result of better diet and vitamins, especially during childhood. But certainly there must be slight changes in human populations over time.
This is why I think that program must have been confused. People are discussing different things. If the question is just 'has natural selection on the human population stopped' then I agree with all the comments made. In the developed world, then probably yes; in the developing world, then certainly not. Just look at sickle cell anaemia as an example if you want one.
Chris, were these triatomine bugs a new species? Could they no longer reproduce with the original population of bugs? Because if not, they have not 'evolved'. If so, then I will unreservedly withdraw my quote, but until then the Creationists have one thing right "that no-one has ever seen evolution operating." Though that is a quite nonsensical argument given that our life-span is only 60-100 years long.
Look at how many breeds of domestic dogs there are. Thousands if not tens of thousands. Some breeds are centuries old. However, breed some mongrels together over several generations and you still get something close to an original dog. It is getting close though, when a Pekinese can no longer mate with a Great Dane then you would have a reproductive barrier.
Evolution needs two things:
1) Environmental stress that favours survival of the fittest by natural selection.
2) A isolating mechanism between populations, either ecological, reproductive or genetic.
Since we are essentially one single population there is no isolating barrier. QED Evolution has stopped.
If we ever colonised space and other planets then an ecological barrier would be the physical barrier of travel between worlds. A reproductive barrier would be a 'Larry Niven' Jinxian human trying to mate with a Crashlander human. A Genetic barrier would be the impossibility (despite Star Trek) of a human mating with a Klingon.
To Dave
A new species has evolved when a new population no longer interbreeds with the old one in the wild. Note : this does not have to be an absolute bar to interbreeding. Sometimes a new species, if placed into captivity, can be essentially 'forced' through lack of choice into interbreeding, and the offspring may be fertile also. It is still a new species because under wild condirtions interbreeding has stopped.
By this definition, evolution into a new species has, indeed, been observed. My favourite example is African cichlid fishes.
http://www.newscientist.com/article/dn18912-fat-lips-evolve-at-record-speed.html
Over 100 years, a sub population of these fishes evolved visibly different lips - thick lips, and stopped interbreeding with the parent species. By definition this was a new species, and it occurred while naturalists were watching and studying them.
With humans, due to slow generations, it will take many thousands of years. What we can observe over a shorter period, though, is changes in gene frequency within the population. This is a new science, and I am sure we will see some interesting data over the next decade or three.
A new species has evolved when a new population no longer interbreeds with the old one in the wild. Note : this does not have to be an absolute bar to interbreeding. Sometimes a new species, if placed into captivity, can be essentially 'forced' through lack of choice into interbreeding, and the offspring may be fertile also. It is still a new species because under wild condirtions interbreeding has stopped.
By this definition, evolution into a new species has, indeed, been observed. My favourite example is African cichlid fishes.
http://www.newscientist.com/article/dn18912-fat-lips-evolve-at-record-speed.html
Over 100 years, a sub population of these fishes evolved visibly different lips - thick lips, and stopped interbreeding with the parent species. By definition this was a new species, and it occurred while naturalists were watching and studying them.
With humans, due to slow generations, it will take many thousands of years. What we can observe over a shorter period, though, is changes in gene frequency within the population. This is a new science, and I am sure we will see some interesting data over the next decade or three.
Okay then, I withdraw; that is an example of evolution almost within the time frame of a human lifespan. You won't win your arguments with creationists so easily though.
Although they cannot, phisiologically reproduce with their wild ( you're trying to tell me those things are tame?) relatives, there might well be intermediate forms that could reproduce with either of them. I do not believe they have yet been declared distinct species, despite entomologists swarming round and trying to lay new names (getting to name a new species is serious kudos).
http://www.scielo.br/pdf/mioc/v94s1/7700.pdf
I will ask Dr Schofield for references; unfortunately I was too ill to go round his place this weekend.
However, he does have another example which is almost certainly speciation, over a slightly longer period. In the Dutch East Indies there is a species of Triatomine which is obviously recently related to the South American ones. ScienceDirect - Acta Tropica : Biosystematics of Old World Triatominae
The most likely explanation is of Dutch sailing boats having carried a small population (possibly just one gravid female) across the Atlantic, and the present species having developed since commerce with the New World.
It's not scientific proof, unfortunately, and a dedicated creationist could say the bugs were part of a species that has since died out in its original habitat, or something. But the suggestions are quite convincing.
I've seen this now, and it was a very balanced programme covering some of the points I made. The 'evolution'/ 'natural selection' thing is just semantics, but I can't see that you can state that 'humans have evolved from cavemen' as someone did. The part about selection of the characteristics of embryos being the future was very interesting. The fact that the presenter misses in her summation at the end is that the 'variation' within our population is probably greater than it has ever been before. If there was some horrible global catastrophe along the lines of the antibiotic-resistant disease, as they were proposing, then millions and millions would no doubt die, but the chances of a few individuals surviving would also be greater than ever before.
I just watched the Horizon programme and, after Googling around for opinions, I came across this site. Some interesting views here, well thought out and eloquently put. Then, there is this quote. Clearly the OP has not thought this through. Perhaps they are unaware that strong morals are the basis of most religions in the world. Or perhaps they simply hate creationists. Whatever the reason, it's a shame that their prejudices have tainted the flavour of this (so far) fascinating discussion. I, as a creationist AND an open-minded science graduate, am perfectly capable of admitting I'm wrong - I'd just like some convincing (as would anyone).
Anyway, back to the intelligent discussion. There seems to be a fair amount evidence pointing to micro-adaptation and pretty much zero pointing to macro-evolution, i.e. the presentation of modern humans millions of years after their aquatic ancestors (as you admit @chrispenycate, convincing suggestions are not scientific laws - ask anyone working on string theory). This lack of scientific proof bothers me and, as such, I can only assume that individual species have remained pretty much as they were created. Science has proved over and over that the simplest and most elegant answer is the correct one, so I live in hope!
Macro-evolution is neither simple nor elegant. It is riddled with inconsistency. There is no definitive law that proves it. Sure, minor adaptation (or extinction) has been observed as a result of environmental conditions, and while this is tempting to extrapolate, it does not prove the theory of macro-evolution. There is nothing inconsistent about creationism. Yes, it sounds daft and it has not been proven; in that regard, it is no different from the theory of evolution. But it's pretty straightforward. So why is it less valid right now?
You may argue that it is naive to believe in a supernatural power. After all, history is replete with tales of the Church being made to look stupid in the face of advancing scientific discovery. I agree with this. The various religions have, at one time or another, been quite short-sighted about aspects of the Universe and its mechanisms.
You may argue that I expect scientific proof, yet I believe in something that is not proven. Again, I agree. Religion and science operate in very different domains. Science depends upon proof. Religion depends upon faith. If your 'thing' is science, then you should be eager to supply your evidence from a scientific standpoint. I will position my faith from a religious standpoint. Neither of us should be offended if we are questioned on our lack of scientific evidence or religious ethics. We may never agree, but we might come to a more tolerant appreciation of our opinions and the fact that we are both trying to understand why the heck we are here.
To me, creationism remains the most convincing argument for the existence of life. Of course, I could be wildly wrong but I'm open to suggestion.
to gihe
My comment to Dave about creationists being too fixed in their views to accept a contrary point is based on personal experience. Of course, you may be the exception. I have no way of knowing.
Perhaps you might look at the reference I posted, showing a fish evolving within 100 years to the point where it no longer interbred with the parent stock, and showed clear cut physical differences. Is this not an example of evolution?
My comment to Dave about creationists being too fixed in their views to accept a contrary point is based on personal experience. Of course, you may be the exception. I have no way of knowing.
Perhaps you might look at the reference I posted, showing a fish evolving within 100 years to the point where it no longer interbred with the parent stock, and showed clear cut physical differences. Is this not an example of evolution?
Heck Tate
The Fleet Footed
Gihe, are you suggesting that some sort of god creating all life exactly as it is now is the simplest and therefore most likely solution? Consider, for a moment, the vast complexity of such a being. Now how did that being come to be? If you actually think about it, any explanation that doesn't involve a creator is simpler by default.
The argument that religion operates outside the boundaries of science is the most naive one you could possibly make, especially after saying that you are open to scientific evidence. It essentially says that your viewpoint is fixed no matter what proof is offered against it, as your god can't ever be touched by science.
As a side note, there are so many inconsistencies with Creationism that it is generally considered a joke by anyone who has cracked open a science textbook. For instance, Young Earth Creationism says the Earth is only around 6,000 years old because the first people were Adam and Eve and only so many generations have come from them. ALL scientific evidence says otherwise. You may want to look up Lucy, the Australopithecus skeleton discovered in 1974 in Ethiopia. The skeleton is over 3 million years old, and is not even the oldest known hominid.
Of course YEC differs greatly from Old Earth Creationism, Progressive Creationism, Gap Creationism, and Day Age Creationism. These are all based on the Bible, but there are also countless forms of creationism based on other religions and not a single one has any shred of evidence backing it.
The argument that religion operates outside the boundaries of science is the most naive one you could possibly make, especially after saying that you are open to scientific evidence. It essentially says that your viewpoint is fixed no matter what proof is offered against it, as your god can't ever be touched by science.
As a side note, there are so many inconsistencies with Creationism that it is generally considered a joke by anyone who has cracked open a science textbook. For instance, Young Earth Creationism says the Earth is only around 6,000 years old because the first people were Adam and Eve and only so many generations have come from them. ALL scientific evidence says otherwise. You may want to look up Lucy, the Australopithecus skeleton discovered in 1974 in Ethiopia. The skeleton is over 3 million years old, and is not even the oldest known hominid.
Of course YEC differs greatly from Old Earth Creationism, Progressive Creationism, Gap Creationism, and Day Age Creationism. These are all based on the Bible, but there are also countless forms of creationism based on other religions and not a single one has any shred of evidence backing it.
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gihe:
Unfortunately, I disagree with your assertion that scientists need any level of proof scientific or otherwise to disagree with the creationist's standpoint.
I only need something that creationists seem happy to accept.
It is enough just to assert that I believe they are wrong.
However, I 'm guilty of approaching (if not actually sticking a size ten boot across
) a line that this site has on religious argument.
All is not lost though, as there is a sister site :-
Interfaith forums - Powered by vBulletin
Where stronger opinions are allowed.
To the Moderators (well Dave and Chris really) if you think this is too much please delete this post, rather than lock the thread.
Unfortunately, I disagree with your assertion that scientists need any level of proof scientific or otherwise to disagree with the creationist's standpoint.
I only need something that creationists seem happy to accept.
It is enough just to assert that I believe they are wrong.
However, I 'm guilty of approaching (if not actually sticking a size ten boot across
) a line that this site has on religious argument.All is not lost though, as there is a sister site :-
Interfaith forums - Powered by vBulletin
Where stronger opinions are allowed.
To the Moderators (well Dave and Chris really) if you think this is too much please delete this post, rather than lock the thread.
gihe - you should take the advice of TheEndIsNigh. These kinds of discussions have a habit of turning nasty and the Interfaith forum is more suitable for them. This was a discussion of the Horizon programme.
Skeptical gave an example of evolution occurring with the lifetime of a human. If you don't accept that you are demonstrating exactly what he said.
Skeptical gave an example of evolution occurring with the lifetime of a human. If you don't accept that you are demonstrating exactly what he said.
cornelius
former axe demon
I've tried to make a mental note of all the points being made, and as a "fan" of the evolutionary psychology- theory, I'm going to try and add my two cents to this thread. First of all- my field of study is communication. Not a "hardcore" science, but more of a science than most people seem to think. I did see the theories that I'll list below in "consumer behavior", but with some personal research and reasoning I'm trying to take it out of the "advertising-game" to apply it on "Everyday life". Some branches of EP try to make a "ground theory" to explain why the human species does what it does, but it's not easy to merge "soft science" and "hard science" without missing some steps and kicking some shins.
Now EP states that we have a "caveman brain" in a modern society. Our brain still reacts more or less the same as it did when we swarmed the African continent. When subjected to tests, people still react to "trees" different then when they see "sand", most people like sweet and fatty food because out in the wild those two meant survival, etc. The theory of neo- neo Darwinism says that there is such a thing as survival of the fittest (most fit as in most adapted to survive, not necessarily the strongest- TO fit, not BEING fit !), but also include genetics, a nature and nurture part in the brain, environment, culture in the broadest sense of the word, and personal preferences that aren’t based on “natural logic” such as survivability, but just personal will, which is a “side-effect” of having such a complex brain. This complex brain is also what makes us different, so making a theory that applies to “all humans” is nearly impossible, you’ll always have exceptions. It just comes down to trying to explain said exceptions.
Evolution within the human species is different all because of that brain. It enables us to have (more or less) a free will, personal preferences and such, changing the way evolution usually works, namely that the fittest species usually are chosen for reproduction. We also have "tricks" to overcome things that evolution would have filtered out, like how physically unfit people can use their intellect to gain influence and possession. Moreover, we do have a “social brain” as well, bringing in a type of relationship most creatures do not have, namely one based on emotions and social bonding. We do see some changes, but those are mostly based on better food, better health and a longer life. One thing that is changing: the so called sexual indicators that prove a man or a woman are “fit” to reproduce with. One example of that are, well… breasts. Most people will say that breasts are for feeding children, which they of course are, but apes have those as well, and you don’t see any of those strut around with a bust that is in a constant “swollen” state. There are some theories to this, most of which I’ll leave out because this is a family forum, but one plausible one is that the storage of fat is an important indicator for survivability for both the infant as the mother. It’s no use “investing” your genes into a pool you’re not sure will survive. But like I said before, it’s difficult to make a theory that applies to every single man or woman. In my opinion, mankind still evolves, but it’s difficult to explain it with the regular evolution theories.
Now as for creationists, I've been thinking about the following. I don't see the bible as an accurate representation of how the world worked, but it was some sort of book of conduct to allow people to make the transition from "Nomad" to "sedentary man". The creation of the earth was put down in simplistic terms, the “unknown” filled in by a force people cannot understand, named God. I transition “all the rules put up in the religious works come from God” to “we should all follow the same baselines as we all come from the same “source”. Why one God? To try and “unite” all people: we all have this “unknown force” in common, so we all have the same God. Different Gods may give people reason to fight about which one is the best God. Unfortunately/ironically this line of thought itself gives root to a lot of violence between religions, while religion was set up to stop violence from happening. Now, along the way, some influential people started to make changes to said religious works, making them into a weapon. In religious works, there’s also evolution, but that evolution is mostly just limited to one “people”. I don’t think the – we are chosen- clause was originally in those works, but that it got added to unite people under a special banner, initially to make everyone abide the laws, and later on for (military) conquest or justification of said conquest.
That’s about it for this post. I hope it’s “on topic” enough. If there are any remarks or questions, I’d be happy to give some more input. I’ve narrowed my post down a lot, as I’m not sure if there is a wordcount.
Now EP states that we have a "caveman brain" in a modern society. Our brain still reacts more or less the same as it did when we swarmed the African continent. When subjected to tests, people still react to "trees" different then when they see "sand", most people like sweet and fatty food because out in the wild those two meant survival, etc. The theory of neo- neo Darwinism says that there is such a thing as survival of the fittest (most fit as in most adapted to survive, not necessarily the strongest- TO fit, not BEING fit !), but also include genetics, a nature and nurture part in the brain, environment, culture in the broadest sense of the word, and personal preferences that aren’t based on “natural logic” such as survivability, but just personal will, which is a “side-effect” of having such a complex brain. This complex brain is also what makes us different, so making a theory that applies to “all humans” is nearly impossible, you’ll always have exceptions. It just comes down to trying to explain said exceptions.
Evolution within the human species is different all because of that brain. It enables us to have (more or less) a free will, personal preferences and such, changing the way evolution usually works, namely that the fittest species usually are chosen for reproduction. We also have "tricks" to overcome things that evolution would have filtered out, like how physically unfit people can use their intellect to gain influence and possession. Moreover, we do have a “social brain” as well, bringing in a type of relationship most creatures do not have, namely one based on emotions and social bonding. We do see some changes, but those are mostly based on better food, better health and a longer life. One thing that is changing: the so called sexual indicators that prove a man or a woman are “fit” to reproduce with. One example of that are, well… breasts. Most people will say that breasts are for feeding children, which they of course are, but apes have those as well, and you don’t see any of those strut around with a bust that is in a constant “swollen” state. There are some theories to this, most of which I’ll leave out because this is a family forum, but one plausible one is that the storage of fat is an important indicator for survivability for both the infant as the mother. It’s no use “investing” your genes into a pool you’re not sure will survive. But like I said before, it’s difficult to make a theory that applies to every single man or woman. In my opinion, mankind still evolves, but it’s difficult to explain it with the regular evolution theories.
Now as for creationists, I've been thinking about the following. I don't see the bible as an accurate representation of how the world worked, but it was some sort of book of conduct to allow people to make the transition from "Nomad" to "sedentary man". The creation of the earth was put down in simplistic terms, the “unknown” filled in by a force people cannot understand, named God. I transition “all the rules put up in the religious works come from God” to “we should all follow the same baselines as we all come from the same “source”. Why one God? To try and “unite” all people: we all have this “unknown force” in common, so we all have the same God. Different Gods may give people reason to fight about which one is the best God. Unfortunately/ironically this line of thought itself gives root to a lot of violence between religions, while religion was set up to stop violence from happening. Now, along the way, some influential people started to make changes to said religious works, making them into a weapon. In religious works, there’s also evolution, but that evolution is mostly just limited to one “people”. I don’t think the – we are chosen- clause was originally in those works, but that it got added to unite people under a special banner, initially to make everyone abide the laws, and later on for (military) conquest or justification of said conquest.
That’s about it for this post. I hope it’s “on topic” enough. If there are any remarks or questions, I’d be happy to give some more input. I’ve narrowed my post down a lot, as I’m not sure if there is a wordcount.
I was under the impression that Evolution has been proven. (notice the capital E)
http://en.wikipedia.org/wiki/Evolution
Evolution of mammalian auditory ossicles - Wikipedia, the free encyclopedia
The evolution over many years of the reptilian to the mammalian jaw including the creation (through changing) of the middle earbones.
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