our ancestors are not supposed to be the apes or of some same kind!

[chemilover]

hello to all there lovely biologists

 

 

i dont have much knowledge about our ancestors neither i ever studied much about it but a bit interested in

recently i studied an opposition to the Darwin's theory that our ancestors are supposed to be the mammals living in the water the reason behind this argument is that iif it were apes or monkeys then how could they breed the generation of same kind throughout the world as they could not travel all around in that era instead water organism could travel easily from continent to continent and they only have to change the fins into hands a little more genetic change

i m confused i neither satisfied with Darwin nor i pursue such above argument so what could likely be our ancestors according to science?

 

 

thanx

[Bluenoise]

Uhhh with current molecular biological techniques no one really takes these theories seriously.

 

Plus what's wrong with the idea that our ancestors simply walked to their locations? or built small boats?

[Dark Photon]

i dont even think you considered your response. is is not possible by yout very own argument that such aquatic lifeforms evolved into apes and then into humans. heres a diagram:

 

aquatic lifeforms ---> humans HUGE GAP

 

aquatic lifeforms -- ............. ---> Apes -----> Humans

evolution even though discreet can be though of as continous, there is no disctinct point in which one form becomes another. evolution is complex and a huge jump from an aquatic form to a human is not happening.... there are just too many features to adapt at once.

 

besides there are many ways in which the ancestors to humans could have traveled.

[insane_alien]

.... there are just too many features to adapt at once.

 

and here we find a common fallacy. it doesn't get adapted at once.

 

its thought that we came from something like a lungfish. the lungfish stayed on land more often(more food or destruction of habitat) so they evolved into a land fairing animal this split up into everything that walks on land today pretty much. eventually out popped ape like creature and out them popped us. this took hundereds of millions of years and not everything changed at once. it all did so slowly. we even think that we picked up our spines from plants somewhere back along the line.

[Mokele]

we even think that we picked up our spines from plants somewhere back along the line.

 

Actually, no. The first multicellular animals seem to have evolved independently from the first multicellular plants. Those first animals were rather wormlike, and somewhere along the line, the worms with and internal supporting notochord did better in one niche.

 

Mokele

[lucaspa]

hello to all there lovely biologists

 

 

i dont have much knowledge about our ancestors neither i ever studied much about it but a bit interested in

recently i studied an opposition to the Darwin's theory that our ancestors are supposed to be the mammals living in the water the reason behind this argument is that iif it were apes or monkeys then how could they breed the generation of same kind throughout the world as they could not travel all around in that era instead water organism could travel easily from continent to continent and they only have to change the fins into hands a little more genetic change

i m confused i neither satisfied with Darwin nor i pursue such above argument so what could likely be our ancestors according to science?

 

In the sticky thread "Human evolution" the last post is mine tracing our ancestry thru transitional individuals to A. afarensis.

 

There was a hypothesis advanced called the "aquatic ape" hypothesis. The hypothesis tried to account for our relative hairlessness by saying that one of our ancestors after our lineage separated from that of apes lived predominantly in the lakes and streams of East Africa, or in the adjacent Indian Ocean. It does not contradict Darwinism but simply hypothesizes how the species between the ape-human split and A. afarensis lived.

 

The aquatic ape hypothesis has been discarded. It simply did not work and caused more problems accounting for our features than it solved.

 

 

thanx

[lucaspa]

and here we find a common fallacy. it doesn't get adapted at once.

 

its thought that we came from something like a lungfish. the lungfish stayed on land more often(more food or destruction of habitat) so they evolved into a land fairing animal this split up into everything that walks on land today pretty much. eventually out popped ape like creature and out them popped us. this took hundereds of millions of years and not everything changed at once. it all did so slowly. we even think that we picked up our spines from plants somewhere back along the line.

 

This seems to be the common ancestor of amphibians, reptiles, and mammals:

 

2. J A Clack, A new early Carboniferous tetrapod with a melange of crown-group characters Nature 394, 66: 1998 (July 2).

4. H Gee, Relics: The creature from the black lagoon

http://www.nature.com/Nature2/serve?SID=64824792&CAT=Corner&PG=Update/update662.html Transitional fossil between amphibians, reptiles, and mammals.

[insane_alien]

close enough for government work, i haven't even done biology since i was 14.

[lucaspa]

close enough for government work, i haven't even done biology since i was 14.

 

I gave you the citation for your information. How old are you now?

 

Don't you think you should do some library research so that you know what the current data is?

[Ophiolite]

The aquatic ape hypothesis has been discarded. It simply did not work and caused more problems accounting for our features than it solved.

Since it was never accepted by any in the anthropological community I don't quite see how it could be discarded.

It certainly offers considerably more meat than the discredited savannah theory, and contrary to what you say is beginning to garner some support in various quarters.

[lucaspa]

Since it was never accepted by any in the anthropological community I don't quite see how it could be discarded.

It certainly offers considerably more meat than the discredited savannah theory, and contrary to what you say is beginning to garner some support in various quarters.

 

We can "discard" a theory without it having formal acceptance in a society. "Discard" is simply the consensus that the theory is wrong.

 

Can you please explain what you mean by "It certainly offers considerably more meat than the discredited savannah theory"? It appears that we are not dealing with a dichotomy -- aquatic or savannah. http://en.wikipedia.org/wiki/Savanna_Theory

 

There are other theories out there, such as "mosaic" and a new "littoral" theory on where humans have lived.

 

Also, if the aquatic ape theory is "beginning to garner some support", can you be more specific? Where? What papers have recently been published on it?

 

I find a 1997 paper below, and nothing more recent in PubMed:

 

Umbrella hypotheses and parsimony in human evolution: a critique of the Aquatic Ape Hypothesis.Langdon JH.

Department of Biology, University of Indianapolis, Indiana 46227, USA.

 

"Conventionally, anthropologists have sought to explain a multitude of unique features of modern humans as the outcome of a single adaptive breakthrough. These "umbrella hypotheses" are aesthetically appealing because they appear to be parsimonious. As internally consistent hypotheses about the past, they are very difficult to prove incorrect in an absolute sense. Anthropology has often rejected them by consensus without developing explicit reasons. This essay explores one example of these models, the Aquatic Ape Hypothesis, the proponents of which continue to argue that they have not received a fair hearing among anthropologists. The hypothesis is troubled by inconsistencies and has not been reconciled with the fossil record. More importantly, its claim to parsimony is false. The numerous "explanations" for individual anatomical traits that it generates constitute premises that are not better founded than competing terrestrial "explanations". The unifying theme of aquatic adaptation is considerably less parsimonious than the assumption that our lineage has always been terrestrial. Finally, the mosaic pattern of hominid evolution demonstrated by the fossil record will not support this or any single cause theory. Most of these criticisms have been previously voiced in one form or another, yet umbrella hypotheses ranging from mainstream science to the paranormal maintain their popularity among students, general audiences, and scholars in neighboring disciplines. One reason for this is that simple answers, however wrong, are easier to communicate and are more readily accepted than the more sound but more complex solutions. Evolutionary science must wrestle with this problem both in its own community and in the education of the public."

[insane_alien]

I gave you the citation for your information. How old are you now?

 

Don't you think you should do some library research so that you know what the current data is?

 

yeah, thanks for the citation.

 

i'm 19 now, i really just can't be bothered with biology. there are a few small interesting bits i'll admit but most of of it is quite tedious to me.

[lucaspa]

yeah, thanks for the citation.

 

i'm 19 now, i really just can't be bothered with biology. there are a few small interesting bits i'll admit but most of of it is quite tedious to me.

 

You're welcome.

 

LOL! you are going from biology you got in Middle School? Just how detailed do you think that could have been?

 

OK, if biology is tedious and you haven't even looked at it since a Middle School class 5 years ago (you didn't take high school biology?), then let me suggest that you lurk and, if not lurking, ask questions? It's OK that you "can't be bothered with biology", we all have different interests. But that attitude severely limits the contribution you can make to a discussion involving biology. Your data was superficial at best, is now half-forgotten, and you aren't seeking more education in the subject.

[insane_alien]

um, i'm from the UK. there is no middle school. anyway, i have actually researched a bit on evolution of humans as i like making creationists look a bit thick. i like to make sure i'm not talking total gibberish.

[lucaspa]

um, i'm from the UK. there is no middle school. anyway, i have actually researched a bit on evolution of humans as i like making creationists look a bit thick. i like to make sure i'm not talking total gibberish.

 

Good for you! Fortunately, you've got a good Sticky thread in this forum on the evolution of humans. My contribution is the last post listing some of the transitional individuals connecting species to species in our ancestry.

[bombus]

In the sticky thread "Human evolution" the last post is mine tracing our ancestry thru transitional individuals to A. afarensis.

 

There was a hypothesis advanced called the "aquatic ape" hypothesis. The hypothesis tried to account for our relative hairlessness by saying that one of our ancestors after our lineage separated from that of apes lived predominantly in the lakes and streams of East Africa, or in the adjacent Indian Ocean. It does not contradict Darwinism but simply hypothesizes how the species between the ape-human split and A. afarensis lived.

 

The aquatic ape hypothesis has been discarded. It simply did not work and caused more problems accounting for our features than it solved.

 

 

thanx

 

Been discarded indeed! It's the most plausible explanation to date, and is gaining more supporters as the evidence piles up. It's just been largely ignored because, like all new theories, people cling on to the old ones for as long as they possibly can.

 

Which problems does it cause rather than solve exactly? The savannah theory is the one that really throws up problems and explains nothing very well...

[lucaspa]

Been discarded indeed! It's the most plausible explanation to date, and is gaining more supporters as the evidence piles up.

 

Go up a couple of posts and you see my response to this. I can't find any papers supporting the aquatic ape theory. Instead, I find papers that discredit it. I posted the citation and abstract of one of these.

 

I'll ask the question again: if the aquatic ape theory is gaining support, where are the papers?

 

If It's just been largely ignored because, like all new theories,

 

It's not all that "new". It's been around since the 1960s. Punctuated equilibrium started around then, and it is accepted, not being hotly debated like aquatic ape theory.

 

I found this description at Wikipedia:

"Since the 1960s, the theory hasn't changed much nor increased its testable predictions; in most respects it has become less specific as objections have been proposed (Ellis 1993, Verhaegen et al. 2002, Morgan 1982, Hardy 1960). The theory has become less specific as to time period ranging from many thousands of years ago to millions. The theory is purported to explain bipedalism several million years ago, hairlessness many thousands of years ago [5], or the increased fat much more recently. The water source is either freshwater or seawater or some combination of the two, often depending on the objection or trait the theory is explaining. " http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis

 

What this tells me is that the theory is not working. Instead, by becoming "less specific" the theory is trying to avoid falsification. This is a common tactic to avoid falsification. The classic example is creationism/ID. One reason Kitcher says Flood Geology fails is that it offers no specifics. It appears the aquatic ape theory is in the same position.

 

The savannah theory is the one that really throws up problems and explains nothing very well...

 

I'm not advocating any theory. But I would note that this is false dichotomy. How well the "savannah theory" or any other alternative theories on human evolution explain things has nothing to do with aquatic ape. After all, all the currently proposed theories may be wrong. So this objection doesn't help aquatic ape theory. Aquatic ape has to stand on its own and, from the papers I see, it doesn't do very well and has been discarded. If that changes in the future, then I will change what I post. I'm simply calling them as I see them.

[CDarwin]

One of my biggest problems with Aquatic Ape (other than the whole no evidence thing): Human breathing. We breath down the same tube we drink, it's a necessary result of the arrangement of the throat for speech. That has an unfortunate effect of leaving us vulnerable to choking; not very adaptive for aquatic life.

 

Not that aquadic ape is at all a refutation of Darwinism anyway. It's still adaptation and natural selection. If you want to go into "non-Darwinian" mechanisms of human evolution you'd be looking at Haekel's Biogenic Law or Bolk's Fetalization Theory, both of those concern deterministic changes in development that yield "progressive evolution" independent of selection.

 

I'm not a big fan of savannah theory, either. I kind of like "big forest brachiator." What happens if a gibbon gains 30kg? He startes walking on the ground more. Brachiators live vertically already and walk bipedally. I'm about to get into Stanford's Upright so I'll probably be able to speak a bit more intelligently on the subject soon...

[lucaspa]

One of my biggest problems with Aquatic Ape (other than the whole no evidence thing):

 

That isn't accurate. AA proponents do point to evidence. It's circumstantial. What I think you mean is "no direct fossils of hominids living i the water"

 

Human breathing. We breath down the same tube we drink, it's a necessary result of the arrangement of the throat for speech. That has an unfortunate effect of leaving us vulnerable to choking; not very adaptive for aquatic life.

 

I'm not sure that is a valid objection. After all, I think sea otters, sealions, and seals all breathe thru the same tube that they eat and drink from. I don't think the AA ape theory ever said that hominids were completely adapted to water. Instead, the theory states that hominids, at some point in evolution, lived predominantly in water and became partially adapted.

[CDarwin]

That isn't accurate. AA proponents do point to evidence. It's circumstantial. What I think you mean is "no direct fossils of hominids living i the water"

 

I'm not sure that is a valid objection. After all, I think sea otters, sealions, and seals all breathe thru the same tube that they eat and drink from. I don't think the AA ape theory ever said that hominids were completely adapted to water. Instead, the theory states that hominids, at some point in evolution, lived predominantly in water and became partially adapted.

 

Well if you want to get nitpicky, I don't think its right to say humans were partially adapted to water; we would be fully adapted to a life partially in water. An omnivore isn't an imperfect carnivore, and an edge species isn't an imperfect forest species. They have specific adaptations to a specific mode of life.

 

There's more than just a lack of fossil evidence, though. There are also no modern aquatic primates that can be looked to. Bonobos wade when crossing streams but they don't live like that and they're not obligate bipeds because of it. The most aquatic species are swimming monkeys like talapoins that have few similarities to humans.

 

I take your second point, though.

 

There are three questions I have concerning Aquatic Ape (I'm not saying these haven't been answered, I'm just curious):

 

What did human ancestors eat as aquatic mammals? I don't see Homo erectus swimming down a salmon. Shellfish? Algae?

 

Why did our ancestors leave the water and when?

[lucaspa]

Well if you want to get nitpicky, I don't think its right to say humans were partially adapted to water; we would be fully adapted to a life partially in water.

 

I phrased my point carelessly. As far as I read AA theory, they are saying that hominids at one time were analogous to sealions, seals, or penguins. That is, they were not fully aquatic like dolphins and whales, but spent a lot of time in the water, acquiring adaptations for that lifestyle: hairlessness, the remaining hair arranged so that it is optimized for movement thru water, controlled breathing, etc. Under those conditions, the theory would not expect every adaptation to a fully aquatic environment, such as separate air passages. Instead, there would be a mosaic of features, some for swimming and some for land.

 

Here's a broad definition of AA:

"The Aquatic Ape Hypothesis (AAH): The hypothesis that water has acted as an agent of selection in the evolution of humans more than it has in the evolution of our ape cousins. And that, as a result, many of the major physical differences between humans and the other apes may be explained, to a large extent, as adaptations to moving (wading, swimming and/or diving) better through various aquatic media and from greater feeding on resources that might be procured from such habitats."

 

Notice that this is very vague. How much time was spent wading, swimming, and/or diving? What resources? When in our ancestry?

 

There's more than just a lack of fossil evidence, though.

 

Oh, there are LOTS of problems with AA theory. I'm not an advocate. If anything, I think the available evidence is against it. I was looking at your specific objections and testing them.

 

Bonobos wade when crossing streams but they don't live like that and they're not obligate bipeds because of it.

 

That's a good point. AA proponents are not good at looking at contrary evidence.

 

What did human ancestors eat as aquatic mammals? I don't see Homo erectus swimming down a salmon. Shellfish? Algae?

 

Another good point. From what I have read, AA says that our precision grip came from picking up and opening shellfish. However, you don't necessarily have to swim a lot to do that. And yes, hominids would not have been good enough swimmers to catch fish just by swimming and using their hands. Seals and sealions are good enough swimmers to catch fish. But their adaptations to living in the water are more extensive than humans'.

 

Why did our ancestors leave the water and when?

 

Another good question and one that I don't see AA address. That is part of the vagueness of the theory. If you look at the definition of AA above, it might be inferred that humans never totally left the water -- because they were never totally in it. That humans still live beside bodies of water (a lot) and exploit the resources in it.

 

I get the impression that part of AA theory is a strawman of "savannah theory". They think the savannah theory prohibits any contact of hominids with water. http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis

 

I found a paper thru PubMed in 2006: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=16263222&query_hl=1&itool=pubmed_docsum

 

This paper seems to lie within the AA hypothesis and I took the time to look at the full paper. Williams hypothesizes that hominids had 2 periods of selection by contact with water: one with the bipedal late Miocene hominoid Oreopithecus bambolii, and another at the inception of H. sapiens. I have several problems with that hypothesis and Williams' reasoning, but at least he got specific.

[lucaspa]

CDarwin, this site seems an honest attempt to critique AAH:

http://www.aquaticape.org/

 

I haven't read the entire site, so some of the criticisms may not be valid. But some are.

 

Criticisms don't get a free ride. They are also critiqued. And the critique of the criticisms is also critiqued. And so on. At some point the ideas are valid and can't be validly criticized. But you don't know that point unless you do the testing.

[CDarwin]

Thank you, very informative.

[Mokele]

hairlessness, the remaining hair arranged so that it is optimized for movement thru water,

 

Unless I'm missing something, I don't see how either of these is the sort of adaptation to the water we'd expect. Plenty of aquatic mammals have hair, and all aquatic birds have feathers. Aquatic reptiles are actually more likely to have ridged (technically 'keeled') scales than smooth.

 

The orientation of the hair is just stupid; the affect of hair on drag in minimal in comparison to the overall streamlining of the body shape. Primates are NOT hydrodynamic, and altering body proportions and shape would be *much* more productive than just re-arranging and losing hair.

 

From a biomechanical standpoint, the AA hypothesis makes as much sense as claiming Archaeopteryx was a burrower.

 

Mokele

[lucaspa]

Unless I'm missing something, I don't see how either of these is the sort of adaptation to the water we'd expect. Plenty of aquatic mammals have hair, and all aquatic birds have feathers. Aquatic reptiles are actually more likely to have ridged (technically 'keeled') scales than smooth.

 

The orientation of the hair is just stupid; the affect of hair on drag in minimal in comparison to the overall streamlining of the body shape. Primates are NOT hydrodynamic, and altering body proportions and shape would be *much* more productive than just re-arranging and losing hair.

 

Here's the full quote:

"Arguments for Aquatic Ape Hypothesis ... Humans are the only primate species in which, over most of the body, hair is so fine and sparse as to reveal the skin under it. Furthermore, human hair is broadly aligned in such a way as to match fluid flow lines while swimming. Environments known to give rise to naked mammals are tropical (in some larger-sized mammals such as elephants — which are themselves descended from aquatic ancestors — and some rhinoceros species), aquatic (whales, dolphins, walrus, dugongs, and manatees), semi-aquatic or littoral (hippopotamus, babirusas), and subterranean (naked mole rat)." http://en.wikipedia.org/wiki/Aquatic_ape_hypothesis

 

You don't agree with the argument. Fine. I'm not sure I buy either.

 

I only made the point as an illustration that AAH does have "evidence for". It points out what I have been saying repeatedly: there is evidence for almost any hypothesis -- if that is what you are looking for. Therefore, what really counts is evidence against.

 

Now, if we go back to the broad definition of AAH -- "The Aquatic Ape Hypothesis (AAH): The hypothesis that water has acted as an agent of selection in the evolution of humans more than it has in the evolution of our ape cousins. And that, as a result, many of the major physical differences between humans and the other apes may be explained, to a large extent, as adaptations to moving (wading, swimming and/or diving) better through various aquatic media and from greater feeding on resources that might be procured from such habitats." -- the hypothesis becomes very innocuous. It only says that some H. sapiens features are the result of adaptations to moving better thru water. It doesn't say humans lived exclusively in water.

 

It looks to me that what has happened is that some proponents and adversaries have taken the AAH to extremes. You (and I at one point) think that AAH was stating that, at some point, there was a hominid ancestor that was adapted to living exclusively or almost exclusively in water -- such as dolphins or seals. But AAH isn't saying that -- or at least this formulation of AAH isn't saying that.

 

This reminds me of the controversy over Punctuated Equilibrium. As originally stated by Eldredge and Gould, PE simply said that most speciation in the past was by allopatric speciation, and this accounts for the "sudden" appearance of most species in the fossil record -- we were unlikely to hit the exact place and time where the small population gradually transformed to a new species. This doesn't threaten neo-Darwinism at all.

 

But it wasn't long before Gould and others took PE to extremes and made it look like PE was threatening neo-Darwinism. So the objections were not to PE per se, but to the extreme vocalizations of PE and statements that PE refuted neo-Darwinism.

 

In the (mild) statement above about AAH, I don't find anything offensive or inherently false in it. There is a consensus that hominids lived in very small groups -- extended families. So, yes some of these groups of hominids (of successive species) would have lived along streams, lakes, or the ocean and attempted to exploit the food resources there. That would have meant considerable moving thru water and any variation that aided this would have been beneficial in that environment. Gene flow with groups not living next to water would have prevented total adaptation to water but spread some of the adaptations thru the whole species. It would be a classic case of disruptive selection with gene flow to keep the whole population as one species.

 

So, the "mild" form of AAH fits very well within both known evolutionary theory and what we can observe of the lifestyles of "primitive" humans today. As I said, the evidence for AAH is circumstantial and does not rule out all other hypotheses. Your post, Mokele, was an attempt to offer an alternative hypothesis.

 

One bit of falsifying evidence for AAH may be that the places where we have beds showing transition between H. habilis and H. erectus or H. erectus and H. sapiens are not (to my knowledge) adjacent to water or show extensive exploitation of resources in water.