Homo neanderthalensis or Homo sapiens neanderthalensis?

dlofnep

The main concept of the biological species concept, to my understanding - is that a species is grouped by the ability to breed and have fertile offspring. I was reading the Origin of Species section of 'Why Evolution is True' by Jerry Coyne, and I started considering if this classification is indeed infallible.

We know through DNA analysis that Homo Sapiens mated with Neanderthal, which contributes up to 4% of our gene pool. Therefore - if Homo Sapiens and Neanderthal were able to mate - then under the BSC, wouldn't they be classified as the same species, rather than two separate species of the Homo genus?

Does the BSC include 'subspecies' as part of a species classification? If so - then surely, Homo sapiens neanderthalensis must be the correct classification for Neanderthal, rather than Homo neanderthalensis. If that is not the case - then does it not bring the infallibility of the Biological species concept into question?

I dropped Jerry Coyne an e-mail for some clarification, but if anyone can offer some insight in the meantime - I would appreciate it.

Capt'n Midnight

If the offspring are fertile then it's the same species.

A male donkey and a female horse can produce offspring, but they are different species because mules are sterile.

Infallibility of species ? Have a look at the common or garden Seagull as an example of how a new species could be formed gradually.
http://en.wikipedia.org/wiki/Ring_species

dlofnep

I'm familiar with the ring species concept. I was just making a point with regards to the classification of Neanderthal, and that it surely must be Homo sapiens neanderthalensis according to the BSC as Neanderthal and Homo Sapiens must have produced fertile offspring if it is resident in our DNA today.

The reason why it stood out for me is because for all the similarities they share - there are also so many differences. So for any other classification, Neanderthal would surely be a different species of the Homo genus. But under BSC, it is the same species.

dlofnep

dlofnep wrote: »

I started considering if this classification is indeed infallible.

It is fallible. It's much like the definition of life, in that there are generally accepted concepts which are widely used, but no one perfect, universally applicable definition.

There are exceptions to every rule, plus the BSC has one major flaw: it requires sexual reproduction. This isn't only a problem for species that undergo asexual reproduction, but for example (and I know this sounds crazy) we know that a swallow and a horse are two different species, but you're hardly going to be able to test it under the conditions of the BSC, as they will never mate. Similarly (and I can't back this up with references as I don't have the time or energy) the polar bear is being reconsidered as a species as it has been found to be extremely genetically similar to the brown bear, to the point that it may be a subspecies of brown bear, just that it's colour and size are the most noticeable differences so they were assumed to be genetically far apart. But with polar bears moving further south their paths sometimes cross with a brown bear and offspring are produced (if I have time tomorrow I'll look this up to see if the offspring were ever found to be fertile or unfertile). Before recently it was never considered because there was no way to see if they would mate as they're geographically separated.

I'm not sure if I've made sense, but I'm basically saying that as far as I know the BSC is fallible but it's usually the most sensible method to use when two similar species in the same area are being examined, and since that's such a common occurance the concept has gained a lot of weight.

Capt'n Midnight

all domestic dogs are the same species but you are unlikely to get a cross between a chihuahua and an Irish wolfhound

And when you get to bacteria where you can genetic transfer between species thanks to things like plasmids the line can get blurred too