We don't know which species should be classed as 'human'

"We don't know if Neanderthals count as humans, or if chimps do, because we can't agree on the defining features of a human"

I don't think any scientist disagrees that chimps aren't humans. The issue in question here is how far back in our lineage do humans go, vs. some other species.

Given that evolution happens continuously, and not in a discreet way, it is completely impossible to objectively determine precisely when we "became" humans, something which is exacerbated by the fact that we're only looking at fossils.

Perhaps, like porn, we should not try to define it further, but there's no question that, when looking at today's existing species, you know a human when you see "it".

This is very similar to a problem in linguistics (and in some ways "is" a linguistics problem).

You can define what an acorn is, and you can define a tree, but when does an acorn become a tree? Same with baldness. Everyone can identify a bald person and likewise someone who isn't bald, but when do you go from not bald to bald? This incidentally is part of the fundamental debate about abortion (when does a fetus become a child?).

And it is the same here -- we can define a human and "not human" but we're having trouble defining exactly when it goes from one to the next.

I think our difficulty comes from the fact that we are unable to admit how exceptional we are. There is a fad at the moment, and it's been ongoing for a century or more, to assign a degree of banality to the biological classification of the human race.

The obvious problem we all have with this is that we are the ones doing the assigning. I'm reading articles like this on a machine designed and built by humans with, if nothing else, the ability to process mathematical equations at a speed far beyond any normal human ability. We do things that are so obviously exceptional and unique that to classify us alongside chimpanzees due to DNA similarities strikes us all as absurd (because it is).

When the article points out that you wouldn't assign a separate genus to an animal just because it uses tools, they're missing the fact that the difference between a bird using a stick to fetch a seed and one that doesn't is absurdly simplistic relative to LANDING ON THE F--KING MOON. At some point, perhaps something that doesn't factor in for other animals should be factored in for us due to the extreme amounts of difference between my DVR recorder and the special rock a chimp uses break open a nut.

To me, this comes across as biological tunnel vision. Since the differences between other animals fall into simpler categories like appearance and genetics, biologists don't want to introduce something like "behavior" into the mix for fear of it complicating the process. The problem is that in the case of homo sapiens, behavior is an unbelievably big deal.

This debate does not even scratch surface. And I find it bit unsettling.

Most Europeans could claim Neanderthal ancestry, because they shared genes. Question if Neanderthals were human is not even theoretical.

Last Neanderthals walked 35K BC. There are tribes which were isolated for 50K or more years. In theory they have a huge genetic difference, also their morphological difference is big, Does that mean they are separate species? Species are often recognized by their shape rather than genes, for example grizzly and polar bear have practically identical genes.

And great apes? I find it insensible to make them humans, when 50% world population does not have even basic human rights. In Western Countries dogs have more rights than many people.

Bet lets assume that great apes are humans. Does it mean they have legal obligations? Could chimpanzee go to prison for torturing animals (bush babies). What if gang of chimpanzee kills other human?

The book Sapiens: A Brief History of Humankind[1] is relevant here (which I've been reading and thoroughly enjoying recently) if anyone wanted to seek out some longer-form information on this and the topics around human evolution and development. The semantics here are really interesting to me because the book immediately points out that not too long ago there were at least 6 species of human on earth at the same time (going by homo=humans, sapiens is what distinguishes us). That concept had never been so explicitly stated to me before, and I find it really fascinating to unpeel.

[1] http://smile.amazon.com/gp/product/0062316095/ref=s9_simh_gw...

I was always under the impression that species are separated over whether they can breed together successfully or not.

I honestly didn't think it needed to be such a big debate and thought this was long settled. "Can they interbreed?" and if the answer is no, it's a different species.

I'm more interested in who we classify as people. Remember, the word person comes from persona, meaning an actor's mask.

In 2014 it was discovered that a species of Long-finned pilot whales (a type of dolphin) has more neocortical neurons than humans by a factor of two! The neocortex is an area of the brain associated with language and conscious thought.

Do these dolphins count as people? Should we afford them "human" rights? What about other species?

The pig you eat has the same amount of neurons in her cerebral cortex as your cat and dog put together. The cow, more than all three put together. Are they people?

Needs more politics. Not even kidding. Enormous arguments over nothing can be very superficially covered by journalists, but the real, dramatic story is someone might get kicked out of some human studies department or funding grant or chair because fossil XYZ is, or is not, a human fossil. Or someone is agitating for, or against, a department schism creating a new "almost but not really human" department of studies with the right or wrong person as highly paid chair of course in competition with the legacy department. Or someone's tenure depends on rabble rousing enough to get publicity to be seen as relevant. Or someone's hiring or tenure has to be denied for various acceptable or unacceptable demographic membership reasons or maybe just trivialities (this is academics after all) and they need a highly dramatic cover story. Maybe some public museum only gets financial funding for "human fossils" and there's a condo developer eyeing that block of land for redevelopment, and it sure would be convenient if the money dried up.

There's probably a real dramatic story underneath the argument, but the journalist somehow managed to miss it.

"But this conventional definition is not necessarily correct."

Definitions (by definition!) cannot be "correct" or "incorrect". They can only be more useful or less useful.

So what? I'll take Semantics for a half-penny, Alex.

> Either way, [Linnæus's choice of words implied that humans are fundamentally different from everything else … It is an understandable mistake …

Ummm, I'm pretty sure that it wasn't a mistake. Human beings are fundamentally different from anything else on this planet. If you seek a proof, look around.

I know! In the past, whites are called "human". Now, rich people are called "human". I am also colored and I am not a racist. Every century has its own definition on the word, "human", no matter in biology or sociology.

This has been solved.

Featherless biped with broad flat nails.

lol

EDIT: For the record, this was said to be Plato's definition of a human after Diogenes (probably my favorite philosopher/practical joker) brought in a plucked chicken and called it a "man" in response to Plato's original definition of humans as "Featherless bipeds"

Just because we crafted the shoe, doesn't mean we'll make a foot fit in it. "Humanity" is more of an abstract concept that science is usually comfortable with. I think we should look for things to define, and create a word rather than create a word, and then figure out how to define it.

if the living being can naturally procreate with me without technological or medical assistance, and generate an offspring that can also naturally procreate upon reaching maturity, then for sure that living being is human.

I'm with the lumpers because I like the idea of having chimps in my genus. But if the splitters prevail I won't cry a tear over it.

It's useful in this context, after reading the BBC story kindly submitted here, to go to a webpage by a biology professor, Jerry Coyne, who literally wrote the book on speciation and definitions of species.[1] He wrote, in his webpage follow-up to a professional lecture for other biologists,[2]

"But I want to discuss briefly a shorter second piece by Gibbons in the same issue of Science, 'The species problem.' Here she brings up the controversy about whether modern humans, Neandertals, and Denisovans were members of different species or the same species. This question is far more important in dealing with humans than, say, with fruit flies, simply because there were far fewer types of hominins, and anthropologists’ careers depend on whether or not they name a new species. That’s why there are so many species names in the hominin family tree—names that turn on characters as tiny as a few millimeters in the measurement of a tooth. It’s likely that, several million years ago, three or four species of hominin did exist at the same time—and maybe at the same place—giving rise to fanciful scenarios about war and (especially) inter-group mating. . . .

"But that was more than a million years ago. What about the more modern groups of Homo, like Neandertals? According to Ernst Mayr’s biological species concept, which Gibbons describes, individuals are members of the same species if they can mate with each other when they encounter each other in nature, and, critically, produce fertile, viable hybrids. If they can’t, then there must exist genetic barriers to mixing of genes, the so-called 'reproductive isolating barriers' that maintain the integrity of species."

With that issue clarified, we see that anthropologists who find bones in the ground will always have incentive to be "splitters," identifying more rather than fewer species, and the only way to resolve how many species there were is to figure out which ancient hominids could mate and produce viable offspring who in turn could mate again and again produce viable offspring for more generations.

Studies of ancient DNA used to be impossible. It was a big breakthrough the first time an Egyptian mummy (plainly a modern human) had its DNA sequenced. The DNA sequencing of a Neanderthal[3] was a further breakthrough. It's plain now that Neanderthals and "modern humans" were part of the same biological species. The usual reckoning is that any modern human with traceable ancestry to Europe or to Asia probably has genes and gene combinations characteristic of Neanderthals, which have since spread further all over the world.

We are all closely related, and we are related to a great variety of ancient human fossil samples. Where human artifacts and cultural ideas travel, human genes travel, and we are all much more "mixed" and interrelated than people imagined even a decade ago.[4]

[1] Speciation by Jerry A. Coyne and H. Allen Orr

http://www.sinauer.com/speciation.html

[2] "How many species of humans were there?"

https://whyevolutionistrue.wordpress.com/2011/01/28/how-many...

[3] http://humanorigins.si.edu/evidence/genetics/ancient-dna-and...

[4] "Towards a new history and geography of human genes informed by ancient DNA"

http://biorxiv.org/content/biorxiv/early/2014/03/21/003517.f...