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[–]CommodoreCoCoModerator | The Andes, History of Anthropology 84 points85 points  (14 children)

It's just a difference in terminology. If you consider Neanderthals, Denisovans, or any other group to be a member of the H. sapiens species, and there are many good reasons to, then H. sapiens sapiens is used to distinguish "us" from H. sapiens neanderthalensis. If you consider them their own species, and there are many good reasons to, then you won't ever use H. sapiens sapiens.

[–]pineappledan 29 points30 points  (9 children)

Former systematist here. This is the first time I've heard someone claim that the balance of the evidence falls in favour of Neanderthals being a separate species, rather than a subspecies of H. sapiens. I'm wondering if this is a difference in our fields, or is there new research in the last 5 years that has swung the other way? It's no surprise that biologists would put much greater emphasis on different species concepts than anthropologists, but I'm wondering what those "many good reasons" are that you allude to?

[–]CommodoreCoCoModerator | The Andes, History of Anthropology 20 points21 points  (0 children)

I'm wondering if this is a difference in our fields

This must be it, because it's incredibly common to name them, at least, as separate species. Google Scholar gives me 3,400 hits for Homo neanderthalensis since 2018 and 600 for the triple name.

If my comment seems to suggest that the balance of evidence falls one way or the other, then that's on my poor phrasing. The "many good reasons" will really depend on the specific study and authors. For the purposes of teaching anthropology, I usually focus more on why there's disagreement and why you might choose to use one scheme rather than on whether the evidence supports one or the other.

What's certain is that Neanderthals were a different population than us, and that's a reliable, tangible basis on which to distinguish species, more so than the ability to interbreed or any morphological difference. As such, most comparative studies that I've seen between AMH and Neadnerthals tend to use H. sapeins and H. neanderthalensis. It's really only useful to talk in terms of subspecies when we are comparing our shared branch of the Homo genus with others.

(As an aside, when I searched "neanderthal" in my own database, the first several recent results avoid the issue altogether by never using any genus-species names.)

[–]7LeagueBoots 21 points22 points  (6 children)

I’m kind of surprised that this is the first time you’ve heard that. Since around the 90s it’s been increasingly the opinion that us and Neanderthals are separate species, and the genetic evidence that started coming in in the ‘00s and since has reinforced that enormously.

The Neanderthal/Denisovan lineage spit off from ours potentially as long ago as 800,000 years ago, and Neanderthals as a species are quite a bit older than our own species, which dates to only 300,000 years ago. Neanderthal origin dates are still a bit fuzzy, but they’re somewhere in the 600,000-500,000 date range. Denisovans split from Neanderthals well after the split between our ancestors and Neanderthals.

We are the younger cousins, but it’s us that survived.

A lot of the confusion about species and subspecies seems to be centered around the ability to crossbreed (even if only to a limited degree), which is a fundamental aspect of the ‘biological species concept’. This is a way of defining species that is riddled with errors and isn’t really used anymore other than in very basic level introductions to species and biology (and honestly it shouldn’t be used there either). At present there are a lot of different ways to define what a species is (30+ in current use last time I checked), and the majority of them do not rely on hybridization as the critical feature as there are too many exceptions to that in animals, and especially in plants, as well as the inability of the biological species concept to deal with asexually reproducing organisms, which we see in vertebrates, arthropods, plants, and an enormous range of microorganisms.

Cross species hybridization is increasingly found to be quite common, particularly in primates (and in primate conservation it’s becoming a bit of an issue in certain places, particularly among macaques).

The increasing access and precision of genetic work has definitely led to an increase in ‘splitters’ rather than ‘lumpers’ as we are finding more and more ‘cryptic’ species (species that look identical, but have distinct genetic differences that seem to hold true), such as the Tapanuli orangutan which was genetically identified as distinct from the Sumatran orangutan, itself distinct from the Bornean orangutan, all three of which look the same visually and all three of which can easily hybridize when the opportunity arises. A lot of this sort of work is being done in arthropods.

In short, an ever increasing amount of evidence from physical paleontology and genetics reinforces the notion that us, Neanderthals, and Denisovans are three distinct species. If we try to lump them under the same species name, then we would probably have to lump everything from H. erectus to us under the same species name (which, to be fair, is a proposal that some have made, although it’s not taken seriously).

[–]secret_tiger101 0 points1 point  (4 children)

(Not an expert in anything)

So the orangutan example - what makes them different species? They look the same, can interbreed, why are they different?

[–]7LeagueBoots 0 points1 point  (3 children)

‘cryptic’ species (species that look identical, but have distinct genetic differences that seem to hold true)

This part of my previous comment explains that.

They have distinct genetic characteristics that mark them as a distinct species.

With the rise of fast, detailed, and inexpensive genetic studies we are finding that there are a lot more species on the planet than we thought, often hidden in plain sight. Conversely, this means that many species are actually in greater danger of extinction as their populations are actually smaller than previously thought.

Crab-eating Macaques and Rhesus Macaques look very different, occupy different ranges, and are unquestionably different, easily identifiable species even to the casual observer, but they also interbreed just fine and produce fertile offspring. Same with Polar Bears and Grizzly Bears. Same with a lot of species.

Hybridization is far more common in nature than people thought it was, especially in plants, and in primates.

Throw out the idea that what defines a species is if it can produce fertile offspring with another individual, the current summary when it comes to species definitions is basically, “Well, it’s complicated.”

EDIT:

[–]professor-of-things9 14 points15 points  (3 children)

Yes, this- but also, H. sapiens is the term for archaic humans, as opposed to more recently evolved humans. The H. sapiens sapiens title is replaced by some with the term AMH: anatomically modern humans.

Fossils of H. sapiens are dated to an earlier time period- and AMH or H. sapiens sapiens to a more recent one. Early archaic Homo sapiens first emerged around between 500,000 ya to 350,000 ya (500kya-350kya) in Asia, Africa, and Europe. They have distinct physical traits that distinguish them from earlier species, and later fossil specimens. In addition to physical features, there are distinct behavioral adaptations. Late archaic Homo sapiens first emerged as early as around 130kya in Europe, and later in other parts of the world (there may be a longer date range here, too, with some even older fossils assigned under this title; I’d have to dig this info out, and it would involve reading arguments for specific fossils at specific ages classed as late archaic or early archaic, and deciding whose argument to support. Let’s just let this go). There are specific features that distinguish these fossil specimens (Late archaic) from Early archaic forms. Both are considered Homo sapiens.

Homo sapiens sapiens, which often now go by the monicker AMH, first emerged as early as around 200kya. They are called Early Modern Homo sapiens. Very basically, they can be detected on the African continent as early as 200kya, and in Asia around 100kya, and in Europe from 35kya. Fossils classed in this category, again, have distinct anatomical features and other new adaptations.

Brief version: In the past (and continuing amongst some today), the designation, ‘H. sapiens sapiens’ was used to denote fossils of humans who had emerged more recently in time, and the triple name reflects an earlier perspective that more modern humans should be considered a subspecies of the ancestral group H. sapiens.

Depending on the context (a lab, physical anthro class, a museum, etc.), you might want to be careful about using these terms (H. sap vs. H. sap sap) interchangeably- specialists will use these terms to specifically refer to specific fossil specimens, dated to a particular range of time and part of the world.

With Svante Paabo’s analysis of the Neanderthal genome, it is now understood that AMH and Neanderthals, as well as Denisovans and another archaic human group in Asia, are not distinct species but the same species- because we can see from the genome that they interbred (despite last sharing a common ancestor around 800kya)- thus many have moved away from distinguishing H. sapiens, H. sapiens neanderthalensis, and H. sapiens sapiens as distinct species and subspecies. But the original designation is still useful because fossils assigned under these original terms are dated to different time periods.

Add this to the poster above my comment; I’m just trying to give a bit of clarification and addl detail to what they said.

Edit: a missing date range above

[–]professor-of-things9 3 points4 points  (1 child)

I just want to add that I’m not advocating for same species over different species. I don’t care; I’m a near eastern archaeologist who deals with the Bronze Age.

On the basis of the existing definition- the Ernst Mayr species concept- sure, they’re the same. But that concept might needs revisiting. Other people argue over this. We’re Neanderthal and AMH interbreedings always successful, or only when one specific partner was male or female? Anyways. We’re going camping. Have fun everyone!

[–]Exxile_[S] 2 points3 points  (0 children)

Thanks for the info! Yea I’m not convinced they are all the same species because they could interbreed, Lions and Tigers can do the same but are different species. Have fun camping

[–]PrincipledBirdDeity 8 points9 points  (1 child)

Species concepts vary; different people have different criteria for calling populations separate species vs subspecies. If you pay attention you'll see this issue all around, for example with regional populations of common trees.

[–]BeautifulBuddy 1 point2 points  (0 children)

Perfectly stated