I have read a lot of contradictory things on the web. But are humans classified as great apes biologically
Yes and no. The traditional biological nomenclature was that great apes are in the Pongidae family, while human are in the Hominidae family. However, as the Wikipedia article says, the great apes and humans are now often put together in the Hominidae family, because the most recent common ancestor of the other great apes was also an ancestor of humans. (The technical term is that the larger Hominidae family is monophyletic, while the old Pongidae family was not.)
Giles’ answer is better
Nah, we’re not even very good apes.
Man, where’s the grapist when you need him?
According to modern classification standards, based on a principle called cladistics, humans and the great apes belong to the same group. This group is usually referred to the family Hominidae.
Humans and chimpanzees are more closely related to each other than either is to the other two great apes, the gorilla and orangutan. Therefore, according to cladistics, it is not valid to put humans in one group, and separate chimps, gorillas, and orangs in another. You either have to put all of them in one family, or else give each of them their own individual family. The usual practice today is the former.
A number of points:
A lot of sources will still give the traditional classification that humans (and their australopithicene ancestors) are in family Hominidae, while the four or five species of great apes are in Pongidae. For reasons explained elsewhere in this thread, this is not biologically accurate – but it is still common practice in many “reliable” sources.
Cladistics depends on one’s sequencing and selection from among several criteria. Colibri’s answer is accurate using a compendium of possible cladograms, and trying to sort out which are most accurate. Using one set of genetic indices, though, humans are aberrant chimps – the bonobo (pygmy chimp) and man are more closely related than either is to the “true” chimp. Another set of references aligns humans and chimps vs. gorilla, a third the human-chimp-gorilla complex vs. orangutans. And at least one outlier cladogram based on one variable protein fraction suggests humans+gorillas vs. chimps.
Fossil forms are sufficiently scarce and fragmentary that there is a real sense in which interpretation counts for more than evidence in working from them. However, there does seem to be a fairly clear sequence from Ardipithecus through Australopithecus and primitive Homo forms to modern man – with a number of side branches such as the Paranthropines. Rather less work has been done with fossil apes, but there does seem to be a parallel lineage. The man-ape split seems to have been in the early Pliocene, 5 million years back give or take a half million. Do note that interpretation of the fossil sequence to date apparently contradicts the conclusions from the gene- and protein-based cladograms. This will need resolution.
Different environments result in fossils at quite different rates. Anoxic underwater ‘pits,’ for example, are far more important than their rarity would suggest because of the superb opportunity for preservation of soft tissues and of animals without hard parts. What is significant here is that plains and lakeside areas tend to be significantly better than forested and jungle areas at preserving fossils. That fact taken into account, though, the best evidence to date [the late 1990s data I’m familiar with – I stand ready to be corrected] suggests that the common ancestor appears to have been a plains-living generalist – and hence more like its ‘hominid’ descendants than like its ‘pongid’ ones. If this is in fact correct, and not the product of selective preservation, then it would be true that apes are divergent specialists from early man, rather than the other way around.
I’ve never heard this. Do you have a cite?
This is the most common method of dividing the groups by far.
As they say, a picture is worth a thousand words. This picture is probably worth a lot more than that (it’s also in .pdf format). Look for the “You are here” pointer, and zoom in; you’ll see who our evolutionary brethren are, based on assorted criteria (this is what’s called a “supertree”, which is a cladistic tree derived from both morphological and molecular data). It’s also for all of Mammalia, thus it’s tremendous…tremendousness.
Note that it doesn’t provide names for the various clades, but it does show the following: Humans + Pan form a clade (usually called Hominini). Gorilla is our next closest relative (forming, with us and Pan, the clade Homininae), then Pongo (Hominidae), then, farther back, Hylobates (Hominoidea). Hominidae, is, as noted above, more generally known as “The Great Apes”.
Also, according to that supertree, both species of Pan are more closely related to one another than either is to us.
On the bonobo thing, it was an online refrence, but from a professional, technical source, not one of the usual “New Discovery Revises Everything We Thought we Knew” school of journalism. I’ll see if I can recover it. (I downloaded it – on a hard disk that is now defunct.)
At least as far as I know, neither of these is mainline thinking. The general consensus is, as DF has it (and you had in your post as well), that the two chimps are each other’s closest relatives; humans are the next closest relatives of both chimps; gorillas are the next branch out; and then the orang.
Again, I don’t believe I have seen fossil data indicating that the great apes share an ancestor they don’t share with us, which is what it would take for them to constitute a “parallel lineage.”
This post has been Aped by the Apeist!
That link is incredibly cool, though they misspelled Euarchontoglires.
Hottentot Potentate, as a new poster you may not be aware of this, but political commentary, even if intended as a joke, is not permitted in General Questions. It has too much potential to derail threads.
Also, I would point out that the first part of your username is considered a highly offensive racial slur in South Africa. Since we have some posters from there, I would recommend that you change it. Please contact TubaDiva to arrange this; her e-mail is available in About this Message Board.
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Ah, you found it! I saw that “tree” in one of the science journals last month and had been looking for an on-line source. But the link never fully loads for me-- I get the tree, but none of the labels. Other times I just get a blank page. Is there an error in your link, or is it something else?
This widipedia link shows the consesus thinking on the genetic (and evolutionary) relationship of the various extant apes (great and lesser). Time line for the great ape splits are generally thought to be (working backwards in time):
Chimp split from Bonobo: ~2M years ago (not shown in the link, but this is “Pan”)
Human split form Chimp/Bonobo line: 5-6M years ago
Gorilla split from Human/Chimp/Bonobo line: ~7-8M years ago
Orang split form Gorilla/Human/Chimp/Bonobo line: ~ 13M years ago
Recent, more detailed, genetic analysis indicates that the Human and Chimp/Bonobo lines may have split much earlier (on the order of 10M years) only to have merged again a few millions years later before the final split about 5 or 6 M years ago. This latest data is somewhat controversial, though, so I would not say it is the consensus thinking (yet).
Ape fossils not in the human lineage our extremely rare. I believe that the oldest chimp fossils are only about .5M years old.
Is that because of their forest habitat being poor for fossil formation?
You may have to zoom around a bit. I haven’t had any trouble getting it load on a couple PCs, so it may be Acrobat, or your PC or something. I sometimes don’t get the labels when it first loads, but do on subsequent loads, so you might just have to play with it a bit.
That’s generally what is thought.
If I’m reading that PDF correctly, the primates are most closely related to things called scandentia and dermoptera (whatever those are), and the primate-scan-derm clade is most closely related to the rabbits-and-rodents clade, right?
And the reason it’s probably not loading right is that it’s huge: It’s a 1.6 MB PDF file, which means that it’ll unfold into an even huger image when it’s zoomed in enough to actually read anything on it.
Correct. Scandentia = tree shrews, and Dermoptera = “flying lemurs” (which neither fly, nor are they lemurs). As can also be seen from the tree, Rodentia is a monstrous clade within Mammalia. Chiroptera (bats) is up there, too.
Also, Rabbits + Rodents are knows as “Glires”. Scandentia + Dermoptera + Primates = Euarchonta (thus the red “Euarchontoglires”).
One interesting note about this cladogram is that, traditionally, Primates + Scandentia + Dermoptera + Chiroptera are grouped in a clade knows as Archonta. However, in this supertree, Chiroptera are shown to be more closely related to Pholidota (pangolins) + Carnivora + Perissodactyla + Cetartiodactyla (= Pegasoferae). This is a recent change based on molecular analysis (see link). “Archonta” has thus fallen by the wayside.
Note also that this particular arrangement remains controversial.