So how many species of giraffe are there? 1? 6? 11? You’ve got to love how messy and complicated biology is.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
So how many species of giraffe are there? 1? 6? 11? You’ve got to love how messy and complicated biology is.
Who says Creationism isn’t a great simplifying theory?
All of these giraffe species represent one *kind*.
How many damn gaps does that make now?
Goddidit. And they’re all one kind. So there.
/snark
Although biology is indeed messy, it seems like the main messiness is not with the biology but that we insist on using words like “species”, and treating it as if it boolean, rather than completely fuzzy, concept.
Until the various populations are no longer interfertile, it is simply a matter of opinion, since there is always the possibility that they can merge back into one interbreeding population.
I think a key line is this:
“By providing giraffe subspecies with full species status, this will help conservation organizations make plans to save the most threatened populations.”
So it really has more to do with politics than science whether there are 1 or 6 species.
What I want to know is how come giraffes get to have cool names like Giraffa camelopardalis tippelskirchi while we’re stuck with boring old “know thyself”?
Species is more than just a politically useful word. As a biologist, I have know doubt that species exist. The trouble is that there isn’t an all-encompassing definition of species that covers all living things. Some species (particularly plants) cross the fertility barrier quite easily yet somehow remain viable species. And I have no clue what a species of bacteria is…. I leave that to the experts. :-)
I have to say, this is one of the things I love the most about biology. The definition of species just doesn’t work well, no matter how you define it, its completely useless. I don’t know why I love it, but I guess it really is great evidence of how evolution works.
Robbrown has a good point, and indeed the title of the post! It is somewhat ambiguous just what species boundaries are, and therefore the “number of species” is ambiguous. To some extent, our psychological tendency to group things imposes that order. Sure, it’s about breeding compatibility, but some species can mate with each other but still deserve to be called separate species (but can any avoid sterility?) like lion + tiger = liger.
(See http://en.wikipedia.org/wiki/Liger, they’re real.)
The definition of species just doesn’t work well
not perfectly, but well enough to accomplish quite a lot of things.
its completely useless.
I rather think you are overstating that a bit.
In fact, this very article demonstrates that concept is NOT completely useless, as it has lead to a very interesting bit of research into the relationships this group of animals share.
hard to study common descent without at least a semi-workable concept of a species-level dichotomy.
To some extent, our psychological tendency to group things imposes that order.
necessarily so.
try to imagine formulating the entire theory of evolution with no framework of phylogenetics to work under.
don’t confuse pragmatism with accuracy, especially given that we still don’t even have the ability to judge what “accurate” even means as of yet.
think: newtonian mechanics vs. quantum mechanics.
newtonian mechanics are not technically accurate, but they are pragmatic for most intents and purposes.
I do wonder if we will get to a level in biology where we can claim a more accurate style of representation, much like quantum mechanics does, but it will be a while yet, I think.
In the meantime, current systematics is pretty damn pragmatic for the most part.
Where is Wilkins when you need him?
Gregory Kusnick, #5:
Because both species are named after their discoverer. :-)
thadd, #7:
No, you’re way off. Obviously it’s not perfect and never can be, but that shouldn’t come as any surprise to anyone who understands post-Darwinian biology, and at any rate it’s far from useless. Without the concept of a “species,” we’d waste just as much time trying to establish the relationship between one individual giraffe and another as we do now when we compare you to a slug. Species is by far the least arbitrary of all taxonomic levels.
Ichthyic, #10:
What would that even mean? I don’t know. Do you? It’s already been said (even in the title of the original post) that biology is messy. There isn’t some hidden reality of “kinds” just waiting out there to be discovered when we refine our ability to watch giraffes reproduce.
Maybe quantum mechanics is an apt analogy after all, in spite of the way you wanted to use it. Just like a quantum physicist can only make predictions that she knows are inaccurate, but at least she has a pretty good idea of how inaccurate they are, biologists can somewhat inaccurately describe disordered populations in ordered terms and know approximately how wrong they are.
Species are such fuzzy things
Not all are; some are scaly, some have skin, and some are even slimy.
Looking at the title of this article, I misread it to say Spiders are such fuzzy things and was shocked to find giraffes instead of tarantulas.
No one understands why I found the signs for genetic testing to determine the breeds involved in mixed breed dogs to be absurd. I may have to forward this around.
What would that even mean? I don’t know. Do you?
a lot of bloody hard work, that’s what it means AFAICT.
current systematics still has a phenotypic bent; which has been quite pragmatic for hundreds of years, but isn’t entirely accurate (as has become clear over the last few decades).
I’m thinking along the lines of complete genome and epigenome maps for everything.
that would pretty much give us a picture that would allow for a much higher level of accuracy.
what that will end up meaning for systematics is an entirely different question, and one I’m not prepared to answer at this point.
in any case the rough analogy I was trying to draw was comparing newtonian/quantum mechanics to phenotypic/genotypic systematics.
I’m still unsure as to just how pragmatic systematics based on genomes will end up being, but it’s clear that it would certainly be more “accurate”.
but then, I’m just a behavioral ecologist anyway, my knowledge of systematics is only secondary, and than only as detailed as it relates to the particular phylogenetics of the critters I study.
I think of species as being sort of like cloud types. Important classifications that reflect a real difference, but yet imprecise. There’s a gray area between the different types, etc.
Ichthyic, #16:
I’d call that detail, not accuracy. Especially since even a genetic map (or an epigenetic map, whatever that will be by the time we have lots of them) is particular to an individual member of a species. We’ll still be making generalizations based on limited data – accepting a certain degree of inaccuracy as long as we can approximate what degree that is. In other words, I don’t think the “giraffe” genome will really tell us how many species there are.
We’ll still be making generalizations based on limited data
true.
but you have to admit that genomics has had a large impact on the arguments about reshaping systematics over the last few decades.
Hell, i was even get caught in the middle of that just trying to do some simple cladistics on Pomacentrids when I was a grad student at Berkeley. The old guard in the museum of Vert. Zool. vs. Alan Wilson’s lab, for example.
I think the word you’re looking for is baramin. (See, they can even make up terminology like real science!)
#8:
If I remember right, there’s a species of lizard in the Southwestern US than can mate with a closely related species to produce fertile offspring. The catch is the that the offspring are parthenogenetic females that reproduce asexually, without mating. Since there’s no gene flow between the two parent species (only from parents to hybrid daughters), the parents remain genetically distinct populations and can legitimately be considered separate species despite the fact that they can interbreed.
I dunno, have creationists tried to explain away the evolution of plants? They would have some big problems. If you haven’t seen it yet, you should see the Nova documentary on the evolution of flowering plants, “First Flower”. Apparently the first such plant appeared about 120 million years ago.
http://www.pbs.org/wgbh/nova/flower/about.html
http://cosmiclog.msnbc.msn.com/archive/2007/04/17/154931.aspx
You just know there are legions of creationists all over the US wondering if these new species came from chickens, dogs or bananas.
plants create all sorts of headaches for creobots, especially when they start blathering about “information theory” and how evolution doesn’t produce new information.
all you have to do is point them at one of the thousands of examples of genome duplication in plants, followed by mutation and inevitable speciation, and it tends to shut up the smarter ones.
nothing shuts up the complete morons, though.
Quasi related is the situation regarding Pan troglodytus. Currently there are three sub-species. A fourth is being considered, though not yet approved. But then one of the three official sub-species—P. t. schweinfurthi—is being considered for species status. P. t. schweinfurthi also incorporates the Bili Ape population. The so-called lion-killer chimps. Schweinfurth’s Chimpanzee does get listed as a species it is likely the Bili Ape will be promoted to a sub-species of Pan schweinfurthi. Possibly P. s. leomortis. But, considering the number of phenotypical and behavioral differences between the two populations; plus the fact there is little, if any, crossbreeding between the two, we could soon see the Bili Ape gaining species status itself. Pan leomortis has a ring to it, don’t you think?
For real fun consider the matter of the chimpanzee, Oliver. Fellow belonged to an officially recognized sub-species of common chimp. But, that sub-species has a number of morphological and phenotypic differences with the standard chimp. And all through Oliver’s life it was noted that common chimpanzees would not tolerate his presence, and he rather preferred the company of humans over them. Rather restrictive of breeding opportunities one would think. So we are looking to chimpanzees as a genus expanding from two to as many as five different species.
On the practical side, zoos and safari parks need to check whether they have more than one species of giraffe and are inadvertently attempting to cross-breed them.
Scientific names of animals are regulated by the International Code of Zoological Nomenclature, with the admirable goal of promoting professionalism, clarity and accuracy in zoological discourse. For example, you cannot name a taxon after yourself (can name it after your spouse or offspring with the same last name, however.)
Subspecies are widely used in all vertebrate groups except fishes. One can have a whole career as an ichthyologist and never encounter a fish subspecies. Subspecies are basically geographic variants of a species. They are more difficult to recognize and describe than are species because of the defined geographic component. Many biologists do not recognize subspecies classification on the argument that by defining subspecies on the distribution of one or a few variables (such as the spots in giraffes) you may be ignoring patterns of distribution of other variables.
The biological species concept, which I regard fondly, is of least use when populations are not in physical contact. If I have population A over here and population B over there and wonder how many species I have, I would first compare A and B and ask if they are more or less different from each other that the related C and D, which do occur together, and successfuly maintain their separate species status. I can attempt to hybridize A and B. If I am not successful, and it is not my fault, that is good evidence I have two species. If they do hybridize, I have to speculate on whether they would do so, and to what extent, if they were to come together in nature. I would prefer that they did not hybridize.
DNA is very useful in informing us how different populations are at the genetic level. We now know much more about giraffe relationships than we did before.
This is true as far as you go, but a BAD analogy because there is a fundamental difference in what kind of entities are compared. Species (like individuals) inherit their features from ancestors, whereas clouds have no genetics and there is generally no causal connection from any one cloud to the form of a younger one of the same ‘type’, or from a cloud type (e.g. cumulonimbus) today to the same type next year; like the raindrops or ice crystals they comprise, they resemble each other because of the shared underlying physics, topography etc. This sort of distinction is explained well in several of Dawkins’ books, and has also been flogged to death in hundreds of barely readable papers on the philosophy of biology.
Sorry Alan, but you lost me when you said “troglodytus” instead of P. troglodytes. Besides, everyone I know working on chimps agrees there are at least three species within Pan if not five.
I have an idea for an ID experiment.
If there are several species of giraffes, then each species would by definition be an example of macroevolution, which ought not to be able to occur without the Designer’s help. Whereas if there’s just one species, then microevolution would be adequate to explain the subspecies. Thus, differences between giraffe varieties should show evidence of design insofar as those varieties are truly distinct species.
So if ID is a valid scientific theory, it should be possible to determine, via evidence or lack of evidence of design, how many species of giraffe there are.
OK, so let’s all look forward to the DI funding a research program on this, shall we?
So… troglodytes, paniscus, and… ?
(narrans?)
Pygmy Loris,
If you must insist upon perfection, then science is not the field for you.
Fuzzy sets were first distinguished (under another name) because of the usual lack of sharp boundaries between ancestor and descendant species.
I don’t insist upon perfection. Species are so difficult to pin down, but we need something to work with.
Anyway, I’m not sure which sub-species of common chimp are being argued for species status. I can never remember all of their names. I think Groves has said all four sub-species of P. troglodytes should be species. Then again, Groves splits everything :)
that was really sad – the limited numbers of giraffes – I don’t want to live in a world without big cats, giraffes, and other beautiful animals- we really suck
everyone here is an expert- well I don’t claim to be – I just think the giraffe is beautiful- I still have a wax giraffe i got from the zoo like 10 yrs ago…
This is a nice illustration of how science operates. We had a certain amount of information about giraffes, and this lead us to think of them as subspecies. We get some more information, and now we think of them as species. This is the unreliability of science that people who want absolute truth decry. They do not understand that it is the strength of science. Our knowledge of the natural world is, and always will be, incomplete. But science gives us the best understanding we have based on what we know at the moment.
I’ve been through something like the giraffe situation. We did a revision of a fish genus in 1978 and went from five species down to two, with recognition of a number of local populations of one of the species. The local populations did not meet subspecies criteria, so we did not name them. Latest revision, with DNA information, gives us seven species; all but one of the local populations raised to species status.
As another biologist, I certainly have such doubts. In cases where we can’t even pretend to do population biology, such as with most fossils, it’s probably best not to recognize species at all.
In bacteria it’s much easier to just recognize clades. Arbitrarily labeling some of them “species” only adds confusion, as far as I can tell.
“Species” is a very useful word, as long as you make it very clear which of the 25-upwards species concepts you happen to be using at the time.
Don’t confuse the recognition of species, let alone any particular species concept, with the possibility to do phylogenetics!
By default. There are 25 or more species concepts — but there is no family concept at all…
This depends on the species concept.
Frankly, no, but that’s because you botched up the Latin :-}
They are very rare in vertebrate paleontology, too (and IMHO shouldn’t be used there at all).
Worse yet, it isn’t one species concept, it’s two: one is “they can interbreed (under lab conditions)”, the other is “they do interbreed (under normal conditions in the wild)”. When people talk about “the Biological Species Concept”, you can almost never tell which one they mean.
It would be such a nice illustration if people had used the same species concept both times. This is almost certainly not the case — and it’s probably also impossible to find out, because people almost never mention which species concept they are using.
As another biologist, I certainly have such doubts. In cases where we can’t even pretend to do population biology, such as with most fossils, it’s probably best not to recognize species at all.
In bacteria it’s much easier to just recognize clades. Arbitrarily labeling some of them “species” only adds confusion, as far as I can tell.
“Species” is a very useful word, as long as you make it very clear which of the 25-upwards species concepts you happen to be using at the time.
Don’t confuse the recognition of species, let alone any particular species concept, with the possibility to do phylogenetics!
By default. There are 25 or more species concepts — but there is no family concept at all…
This depends on the species concept.
Frankly, no, but that’s because you botched up the Latin :-}
They are very rare in vertebrate paleontology, too (and IMHO shouldn’t be used there at all).
Worse yet, it isn’t one species concept, it’s two: one is “they can interbreed (under lab conditions)”, the other is “they do interbreed (under normal conditions in the wild)”. When people talk about “the Biological Species Concept”, you can almost never tell which one they mean.
It would be such a nice illustration if people had used the same species concept both times. This is almost certainly not the case — and it’s probably also impossible to find out, because people almost never mention which species concept they are using.
Don’t confuse the recognition of species, let alone any particular species concept, with the possibility to do phylogenetics!
don’t confuse what I said as a response to anything other than what i responded to, which was the tendency for humans to group things.
I’m hardly confused about the issue.