Regards the answer by SDSTAFF David, 11 Oct. 1999, on the question of whether humans evolved from apes----Is it correct to say that humans ARE apes? I don’t think so because humans and apes are thought to have evolved in seperate linneages from a common ancestor. Therefore it seems that apes are apes and not humans and humans are humans and not apes.
But many scientists and science students I know [not necessarily evolutionary biologists] claim that the statement “humans are apes” is correct.
The definitive answer is usually something of a moving target in science, but humans descending from nonhumans is pretty much the established understanding of modern biological and paleological sciences.
Specifically, the claim that humans ARE apes has been asserted (or reasserted) by the relatively new discipline called cladistics.
The link does a pretty good job of explaining cladistics; basically, it’s a reorganization of how we categorize living things – one that considers the history of a given living thing’s evolutionary path to become what it is, instead of just its shape. Cladistics therefore does not necessarily categorize animals the same way the older, familiar Linnaean system does; a cladistic chart will contain some surprises.
Take a look at the second diagram on this page – not the one picturing the woman in the business suit, but the one below it that looks a little like Gandalf’s rune, or a very complicated letter Y.
That’s a cladistic arrangement. See how humans branched off the line after gorillas, orangutans, and gibbons? That means that, cladistically speaking at least, we must be in any group that lumps together both gorillas and chimpanzees. Since humans have (in Western scientific tradition anyway) classified both gorillas and chimps as ‘apes’, that means we’re apes as well.
I’m not claiming that I understand everything about cladistics, nor that it is better than other understandings of how to organize our understanding of living things. Cladistics has its controversies; like any new scientific thinking, it’s vital and subject to change. I’m just showing why the claim is made that we are indeed apes.
I think the problem here is that the terms “ape” and “gorilla” are often used interchangeably. Humans are assuredly not gorillas, and we probably did not evolve from gorillas. More properly, however, “ape” is used for a broader category than “gorilla”. “Ape” can refer to a gorilla, or a chimpanzee, or an ourangoutang, or a few other large, non-tailed primates. But any sensible group which includes gorillas and chimpanzees must also include humans, and probably the common ancestor of gorillas, chimps, and humans, as well. So humans and gorillas are both examples of apes, but humans are not gorillas.
Thanks to everyone. Those were great answers and I found them helpful. Thanks, Sailboat, I’ve bookmarked those pages and look forward to studying them. This is an interesting subject and not all that easy to fully comprehend [at least for me].
One of the most common clade definitions within cladistics is that of the “crown group”[sup]1[/sup]. A crown group is basically defined as “the most recent common ancestor of Group A and Group B, plus all its descendants”.
In this case, apes are defined as the most recent common ancestor of humans and gibbons, and all its descendants. The obvious (and most relevant) consequence of this definition is that that most recent common ancestor is itself a member of the gorup being defined. Thus, the most recent common ancestor of all extant apes is, by cladistic definition, itself an ape. Also thus, humans, again by definition, evolved from an ape ancestor.
[sup]1[/sup] A stem-based definition genrally goes along the lines of “all X more closely related to Y than to Z”. The two primary dinosaur clades, Saurischia and Ornithischia, are often defined using a stem-based definition (e.g., Saurischia includes all dinosaurs more closely related to sparrows than to Triceratops).