Human/primate ancestry and the so-called "missing link"

[desertyeti]

And another picky detail...since none of the fossil specimens can be shown to be directly ancestral to each other or modern taxa, it is technically incorrect to refer to them as "ancestors" or "ancestral."

Since out of any species, only a small population actually evolves into another species, the odds against preserving a specimen of that population are astronomically high. Paleontologists and cladists are unanimous in agreeing that no fossil species can be shown to be an ancestor of any other in the true, biological sense. It's best to buffer such statements with temrs like: "a close relative of Sivapithecus was ancestral to Gigantopithecus." or "a Sivapithecus-like ancestor gave rise to Gigantopithecus."

Sorry...the anal-compulsive techno-geek is coming out in me...

And p.s.
I know it's hard to believe that Gigantopithecus might NOT have been a giant, but take a look at the skull of Paranthropus (left) vs. a modern human (right). The teeth and jaw of Paranthropus are physically larger, as are the jaws. Scaling Paranthropus to a modern human using the same calculations that make Gigantopithecus blacki into a 9' tall ape would make Paranthropus approximately 8-9' as well. Yet the stature was still around that of a chimp. Just sayin'...

 

[William Parcher]

Sorry...the anal-compulsive techno-geek is coming out in me...

Me too.

Since out of any species, only a small population actually evolves into another species, the odds of preserving a specimen of that population are astronomically high.

You meant the odds are astronomically low?

 

[desertyeti]

curses...foiled by my own shoddy merchandise!!!!!

 

[Vortigern99]

3. The current trend of saying that human beings are "apes", because we are in the same Superfamily (Hominoidea) as apes, is confusing and unnecessarily broad, since distinctions are made at every level of the taxonomic "tree". More on this in a future post.

I'm looking forward to this, as I know of no taxonomically credible way to retain the term "ape" and not apply it to humans as well. The "let us give names to paraphyletic groups and consider them equivalent to names of monophyletic groups" crowd is thankfully growing smaller every year.

Okay, here's my case. Paraphyly and monophyly do not enter into the discussion, since I'm not proposing a change in any taxonomic classification, at any level. I'm proposing a semantic change, a linguistic return back to the usage that has been employed for decades, if not centuries, in common parlance and in public discussion of anthropological facts.

The term "lesser ape" is already used to distinguish Family Hylobatidae (gibbons and siamangs) from the "great ape" genera (orangs, gorillas and chimps) and humans, all of which are classified under Family Hominidae. If the word "ape" can be used to describe so widely varying animals of different Families, surely the meaning can be narrowed down to distinguish the "great apes" from humans.

In fact, it was once exactly this way -- until very recently, within the last few years, when the meaning of the words was abruptly changed, and suddenly "apes" meant "gibbons & siamangs, orangutans, gorillas, chimps, and humans."

Language is about conveying meaning. If we use the term "ape" to include humans, we've lost the meaning of both words. "Apes" are quadrupedal, furry animals with brain capacities less than 400cc and no precision grip, some of whom employ crude tools but have no art or religion. "Humans" are bipedal, thinly-haired animals with brain capacities (in modern times) of 1600cc and precision grips, all of whom manufacture complex tools and have a multiplicity of arts, sciences and religions. There's quite a gulf, in terms of physiology and behavior, between these two clearly defined groups of so-called "apes"!

In the chart below, we can see several examples of the same distinction being made in common usage of words, which seem to contradict or challenge taxonomic classification. The subOrder Strepsirrhini, for example -- wet-nosed primates -- is generally used to mean "prosimians", but of course tarsiers are prosimians, too... and they're classified under Haplorrhini -- dry-nosed primates, along with monkeys, apes and humans! So in common language, Strepsirrhini means "prosimians which are not tarsiers". Using the same logic, why could not Family Hominidae mean "great apes (which are not humans) AND humans", subFamily Homininae mean "gorillas and chimps (which are apes) AND humans", and Tribe Hominini mean "chimps (which are apes) and humans"?

Again, this is not a challenge to the taxonomic system, the current arrangement of which I agree makes sense. It's about the common, public usage of terms that already have meaning, and have had for a long time.

KINGDOM: Animalia
PHYLUM: Chordata
CLASS: Mammalia
ORDER: Primata
SubORDER: Strepsirrhini (wet-nosed primates - non-tarsier prosimians)
SubORDER: Haplorrhini (dry-nosed primates – tarsiers, monkeys, apes and humans)

InfraORDER: Tarsiiformes(tarsiers)
InfraORDER: Simiiformes (all monkeys, all apes and humans)​

ParvORDER: Platyrrhini (New World monkeys)​

FAMILY: Callitrichidae (marmosets and tamarins)
FAMILY: Cebidae (capuchins and squirrel monkeys)
FAMILY: Aotidae (night or owl monkeys)
FAMILY: Pitheciidae (titis, sakis and uarakis)
FAMILY: Atelidae (spider, howler and wooly monkeys)​

ParvORDER: Catarrhini (Old World monkeys, all apes and humans)​

SuperFAMILY: Cercopithecoidea (Old World monkeys)​

FAMILY: Cercopithecidae (Old World Monkeys)​

SuperFAMILY: Hominoidea (all apes and humans)​

FAMILY: Hylobatidae (lesser apes)​

GENUS: Hylobates (siamangs and gibbons)​

FAMILY: Hominidae (great apes and humans)​

SubFAMILY: Ponginae (orangutans)​

GENUS: Pongo (orangs)​

SubFAMILY: Homininae (gorillas, chimpanzees and humans)​

TRIBE: Gorillini (gorillas)​

GENUS: Gorilla (gorilla)​

TRIBE: Hominini (chimps and humans)​

GENUS: Pan (chimps)
GENUS: Homo (humans)​

 

[makaya325]

Monkeys and the great apes dont share the same common ancestor, correct?

 

[Vortigern99]

Sure they do. If you go back far enough, say about 4 billion years, every species on earth shares a common ancestor!

But I know you're trying to be more specific. Since prosimians (wet-nosed primates or Strepsirrhini) split from monkeys and apes (dry-nosed primates or Haplorrhini) some 40 mya, it stands to reason that monkeys' and apes' common ancestor lived about that time. If it wasn't Darwinius massilae, it was probably a species similar to it.

 

[Vortigern99]

And another picky detail...since none of the fossil specimens can be shown to be directly ancestral to each other or modern taxa, it is technically incorrect to refer to them as "ancestors" or "ancestral."

Since out of any species, only a small population actually evolves into another species, the odds against preserving a specimen of that population are astronomically high. Paleontologists and cladists are unanimous in agreeing that no fossil species can be shown to be an ancestor of any other in the true, biological sense. It's best to buffer such statements with temrs like: "a close relative of Sivapithecus was ancestral to Gigantopithecus." or "a Sivapithecus-like ancestor gave rise to Gigantopithecus."

Sorry...the anal-compulsive techno-geek is coming out in me...

Thank you very much, that is extremely useful information. When I was in the undergrad anthro department at Texas State 20 years ago, the professors and the literature were not that careful about the use of the terms "ancestor" and "ancestral". The words were bandied about as though it were a proven fact: Australopithecus afarensis was the ancestor of homo habilis, h. habilis was ancestral to H. erectus, and H. erectus was the ancestor of H. sapiens with a bit of H. neanderthalensis thrown in to spice things up. I'm simplifying, of course, for the sake of brevity, but in essence that was the approach that my teachers and textbooks taught. It's good to know that the thinking is now more skeptical and more cautious. That's good science all the way around.

And p.s.
I know it's hard to believe that Gigantopithecus might NOT have been a giant, but take a look at the skull of Paranthropus (left) vs. a modern human (right). The teeth and jaw of Paranthropus are physically larger, as are the jaws. Scaling Paranthropus to a modern human using the same calculations that make Gigantopithecus blacki into a 9' tall ape would make Paranthropus approximately 8-9' as well. Yet the stature was still around that of a chimp. Just sayin'...

Fair enough. But have you seen the comparison pic of the G. and H. jaws? The difference is like comparing an orangutan to a lemur. It far outstrips the P. and H. comparison above. I understand what your getting at, and I realize that with no post-cranial remains it's impossible to tell one way or the other, but the animal you're proposing would be man-sized with an unbelievably HUGE jaw and teeth. It just seems a bit of a stretch.

 

[makaya325]

Sure they do. If you go back far enough, say about 4 billion years, every species on earth shares a common ancestor!

But I know you're trying to be more specific. Since prosimians (wet-nosed primates or Strepsirrhini) split from monkeys and apes (dry-nosed primates or Haplorrhini) some 40 mya, it stands to reason that monkeys' and apes' common ancestor lived about that time. If it wasn't Darwinius massilae, it was probably a species similar to it.

assuming Monkeys and Great apes evolved from a recent common ancestor (I mean recent in terms of life on earth), Why is it that monkeys evolved tails while Great apes did not? Could weight be considered a primary reason for the lack of tail in the Great apes?

Next to the great apes, Monkeys are the closest related species to humans, correct?

 

[makaya325]

Fair enough. But have you seen the comparison pic of the G. and H. jaws? The difference is like comparing an orangutan to a lemur. It far outstrips the P. and H. comparison above. I understand what your getting at, and I realize that with no post-cranial remains it's impossible to tell one way or the other, but the animal you're proposing would be man-sized with an unbelievably HUGE jaw and teeth. It just seems a bit of a stretch.[/QUOTE]

Not to mention Giganto's Jaw thickness and length. I also do not think that science has ever viewed Paranthropus as a giant.

 

[MG1962]

Long*. Sorry about that! Im just looking forward to discussing primates without having the big guy involved.

Who? King Kong

 

[Vortigern99]

assuming Monkeys and Great apes evolved from a recent common ancestor (I mean recent in terms of life on earth), Why is it that monkeys evolved tails while Great apes did not? Could weight be considered a primary reason for the lack of tail in the Great apes?

Without examining the question in a published paper, my guess would be that it has to do with the amount of arboreal locomotion a given group of animals is adapted for. In general, apes are less arboreal than monkeys, and so do not require the moving balancing pole offered by a tail.

Next to the great apes, Monkeys are the closest related species to humans, correct?

If you will look at the taxonomic chart I offered, you will see that monkeys are not a species at all, but are divided into two Parvorders, Catarhhini (Old World monkeys, apes and humans) and Platyrrhini (New World monkeys). Go ahead and do some research on your own, please, before you seek a discussion on the topic. Then come back here and I'll be happy to exchange ideas.

 

[Subduction Zone]

This is all very interesting but don't you realize for every "missing link" that you find you introduce another "gap" in the fossil record? Therefore even if you found every link between modern way back to our lemur type ancestors you are just giving almost infinite fuel to the Cretinists (funny my spell checker does not like that word though I am sure it is spelled correctly).

Sometimes I think the only reasonable response to creationshits (spell checker still doesn't like this) is to do the equivalence to the Monty Python fish dance to them. There is such an almost infinite amount of proof supporting evolution that any new finding in it should be looked on in the same way when a biologist announces a new specie of beetle, or an astronomer announces a new, but interesting star. Yes it is interesting, but it does not prove anything we did not know before. But for some reason the religious inspired ignorance of certain groups (this includes a brother of mine, not my brother who does work that influences the International Space Station, I come from a complex family) makes it necessary to continue to defend a theory that is already one of the most well proven theories in the history of science. Oh well, at least it keeps internet arguments interesting.

 

[Vortigern99]

This is all very interesting but don't you realize for every "missing link" that you find you introduce another "gap" in the fossil record? Therefore even if you found every link between modern way back to our lemur type ancestors you are just giving almost infinite fuel to the Cretinists (funny my spell checker does not like that word though I am sure it is spelled correctly).

I'm not sure I follow you. Can you clarify the bolded portion? I don't see what you mean here at all.

Sometimes I think the only reasonable response to creationshits (spell checker still doesn't like this) is to do the equivalence to the Monty Python fish dance to them. There is such an almost infinite amount of proof supporting evolution that any new finding in it should be looked on in the same way when a biologist announces a new specie of beetle, or an astronomer announces a new, but interesting star. Yes it is interesting, but it does not prove anything we did not know before. But for some reason the religious inspired ignorance of certain groups (this includes a brother of mine, not my brother who does work that influences the International Space Station, I come from a complex family) makes it necessary to continue to defend a theory that is already one of the most well proven theories in the history of science. Oh well, at least it keeps internet arguments interesting.

My purpose in authoring this thread was not to take potshots at Creationists (for the record that's the correct spelling ), but if the Spirit moves you, be my guest.

 

[Subduction Zone]

Vortigern I was being a bit facetious. I get tired of creationists, every time you find a "missing link" for them they demand a link in between. In fact I don't like the term "missing link" myself since that name really applies to every fossil ever found. Since evolution is a very slow continuous process it is impossible to say where one specie becomes another.

 

[Dr Adequate]

In fact I don't like the term "missing link" myself since that name really applies to every fossil ever found.

It applies to no fossils that have ever been found, since such fossils are not missing.

 

[Vortigern99]

I'm with you there! The term "missing link" is a media invention, or at the very least a sensationalistic term that the media seizes on to grab headlines every time a new discovery is made in the hominoid fossil record. "Ida"/Darwinius massilae is the latest example of this overreaching generalization. Fine, excellent, we have a 47 myo fossil primate with what could be called prosimian, monkey and human features. Great! Let's discuss it, study it, see what makes it special and unique and wonderful. Let's not piegon-hole it as a "missing link" between species x and species y, as if the only purpose of this ancient animal was to connect monkeys to humans or whatever baloney the media ran with.

 

[makaya325]

Vortigern I was being a bit facetious. I get tired of creationists, every time you find a "missing link" for them they demand a link in between. In fact I don't like the term "missing link" myself since that name really applies to every fossil ever found. Since evolution is a very slow continuous process it is impossible to say where one specie becomes another.

What creationists fail to understand is that "Missing Links" are needed to prove Evolution, which is a scientific fact. What these Bible thumpers fail to realize is that most of the fossil record is either unknown or destroyed.

 

[makaya325]

I Will do that Vort.

 

[Kotatsu]

Okay, here's my case. Paraphyly and monophyly do not enter into the discussion, since I'm not proposing a change in any taxonomic classification, at any level. I'm proposing a semantic change, a linguistic return back to the usage that has been employed for decades, if not centuries, in common parlance and in public discussion of anthropological facts.

Well, you are proposing a taxonomic change of vernacular names, which, admittedly, are not governed by the Code.

The term "lesser ape" is already used to distinguish Family Hylobatidae (gibbons and siamangs) from the "great ape" genera (orangs, gorillas and chimps) and humans, all of which are classified under Family Hominidae. If the word "ape" can be used to describe so widely varying animals of different Families, surely the meaning can be narrowed down to distinguish the "great apes" from humans.

In short: no.

For a longer answer, the ideal would be to have vernacular names corresponding exactly to scientific names. This is what at least the taxonomic community is always striving for. The current Swedish Taxonomic Initiative (which fund me), for instance, has as a name-giving rule for Swedish vernacular names that they shall refer only to groups that have been shown or are believed to be monophyletic.

Doing so produces the highest usefulness of a taxonomic system, regardless of the kind. Under such a scheme, it truly doesn't matter which name you use: they would refer to the same set of organisms anyway, and the layman and the expert would automatically be talking about the same thing, which would remove at least one level of potential misunderstanding.

You are narrowing a vernacular name down to a set of organisms that does not form a monophyletic group, and thus there can be no exact correspondence between the vernacular names and the scientific ones, and in the process, you make the vernacular name pointless. It then describes all the organisms that display the characters of Hominidae except some, and then you waltz into paraphyly whether you like it or not. This might potentially, if carried to extremes, introduce further misunderstandings between laymen and experts.

There is also the point that "lesser apes" is a perfectly reasonable name for -- what I assume is -- a monophyletic group, but one which has no bearing on the validity or usefulness of the paraphyletic term "apes". The existence of the word "lesser" essentially makes the whole term independent of "apes" as in Homonidae, in the same way that "seahorse" is taxonomically independent of "horse" and "treeshrew" is independent of "shrew".

In fact, it was once exactly this way -- until very recently, within the last few years, when the meaning of the words was abruptly changed, and suddenly "apes" meant "gibbons & siamangs, orangutans, gorillas, chimps, and humans."

Which I see as a good thing, as that means that the vernacular and the scientific taxonomies are being aligned, which will, in the long run, likely lessen misunderstandings.

Language is about conveying meaning. If we use the term "ape" to include humans, we've lost the meaning of both words. "Apes" are quadrupedal, furry animals with brain capacities less than 400cc and no precision grip, some of whom employ crude tools but have no art or religion. "Humans" are bipedal, thinly-haired animals with brain capacities (in modern times) of 1600cc and precision grips, all of whom manufacture complex tools and have a multiplicity of arts, sciences and religions. There's quite a gulf, in terms of physiology and behavior, between these two clearly defined groups of so-called "apes"!

But humans, compared to non-Hominids, are basically a collection of somewhat aberrant apes.

In the chart below, we can see several examples of the same distinction being made in common usage of words, which seem to contradict or challenge taxonomic classification. The subOrder Strepsirrhini, for example -- wet-nosed primates -- is generally used to mean "prosimians", but of course tarsiers are prosimians, too... and they're classified under Haplorrhini -- dry-nosed primates, along with monkeys, apes and humans! So in common language, Strepsirrhini means "prosimians which are not tarsiers". Using the same logic, why could not Family Hominidae mean "great apes (which are not humans) AND humans", subFamily Homininae mean "gorillas and chimps (which are apes) AND humans", and Tribe Hominini mean "chimps (which are apes) and humans"?

A more useful distinction would be to remove the tarsiers or the Strepsirrhini from the term "prosimian", and have that word denote a monophyletic group. I find the use of "prosimian" you describe to be as wrong as your use of "ape", as both apparently denote paraphyletic groups, and they are an evil that should be destroyed, not a template to emulate.

Again, this is not a challenge to the taxonomic system, the current arrangement of which I agree makes sense. It's about the common, public usage of terms that already have meaning, and have had for a long time.

And that usage is, I assume, based on an incorrect understanding of how things are related. I don't feel that perpetuating a wrong that we are familiar with, for the sake of familiarity, in any way outweighs the gains of having scientific and vernacular names denoting the same set of individuals so that there will be less misunderstandings.

 

[sphenisc]

Well, you are proposing a taxonomic change of vernacular names, which, admittedly, are not governed by the Code.



In short: no.

For a longer answer, the ideal would be to have vernacular names corresponding exactly to scientific names. This is what at least the taxonomic community is always striving for. The current Swedish Taxonomic Initiative (which fund me), for instance, has as a name-giving rule for Swedish vernacular names that they shall refer only to groups that have been shown or are believed to be monophyletic.

Doing so produces the highest usefulness of a taxonomic system, regardless of the kind. Under such a scheme, it truly doesn't matter which name you use: they would refer to the same set of organisms anyway, and the layman and the expert would automatically be talking about the same thing, which would remove at least one level of potential misunderstanding.

You are narrowing a vernacular name down to a set of organisms that does not form a monophyletic group, and thus there can be no exact correspondence between the vernacular names and the scientific ones, and in the process, you make the vernacular name pointless. It then describes all the organisms that display the characters of Hominidae except some, and then you waltz into paraphyly whether you like it or not. This might potentially, if carried to extremes, introduce further misunderstandings between laymen and experts.

There is also the point that "lesser apes" is a perfectly reasonable name for -- what I assume is -- a monophyletic group, but one which has no bearing on the validity or usefulness of the paraphyletic term "apes". The existence of the word "lesser" essentially makes the whole term independent of "apes" as in Homonidae, in the same way that "seahorse" is taxonomically independent of "horse" and "treeshrew" is independent of "shrew".



Which I see as a good thing, as that means that the vernacular and the scientific taxonomies are being aligned, which will, in the long run, likely lessen misunderstandings.



But humans, compared to non-Hominids, are basically a collection of somewhat aberrant apes.



A more useful distinction would be to remove the tarsiers or the Strepsirrhini from the term "prosimian", and have that word denote a monophyletic group. I find the use of "prosimian" you describe to be as wrong as your use of "ape", as both apparently denote paraphyletic groups, and they are an evil that should be destroyed, not a template to emulate.



And that usage is, I assume, based on an incorrect understanding of how things are related. I don't feel that perpetuating a wrong that we are familiar with, for the sake of familiarity, in any way outweighs the gains of having scientific and vernacular names denoting the same set of individuals so that there will be less misunderstandings.

But laypeople have other priorities than taxonomy, they like having the term "apes" available for non-human hominoids. If Edgar Rice Burroughs had written "Tarzan of the non-human apes", I don't think it would have done so well.

Likewise "Cargoes" just wouldn't scan.

QUINQUIREME of Nineveh from distant Ophir,
Rowing home to haven in sunny Palestine,
With a cargo of ivory, and non-human apes and peacocks,
Sandalwood, cedarwood, and sweet white wine.

The Swedish Taxonomic Initiative isn't paying the public to follow their rules. More the other way around. We've already agreed to stop calling bats "birds", (though we still refer to "flying vertebrates" when you aren't listening), and many have even managed to introduce "Barbary Macaque" and "Crested Macaque" to their vocabulary, if somewhat grudgingly.

But here's where they draw the line, humans ain't apes. The public use a whole variety of non-taxonomic terms, words like "seafood", "pets", "herbs" and "vermin". They have uses for language other than taxonomy, and insisting on calling humans "apes" is a step too far. So if you want to communicate clearly with them then you're just going to have to make the effort and substitute "hominoids" with "apes and humans". I know it's asking a lot, but not doing it would just be shellfish.