On taxonomy: should there be multiple human species/ subspecies

faaip_de_oiad · May 2006

Ok, this is not a racist thread, first and foremost. I'm raising the question from a genetics and taxonomic point of view.

Is it scientifically sound for us to give different scientific names for animals with minimal differences and yet not give different names for people. The variation among the Homo sapiens sapiens is simply so great that it's hard to fathom why it only falls under one taxonomic umbrella.

Take the Asian and African elephants for example. They only have minimal differences in size and trunk features, but they have different scientific names. I'm wondering, if the Asian and African elephant were to mate, will they be able to conceive?

hotchillipepper · May 2006

double post again... server is too busy.. we need to upgrade some roads here..

hotchillipepper · May 2006

sure, why not? crossbreading is possible, BUT, only animals that are close related can crossbread, its not possible if they are far relatives....

lion and tigers had been crossbread, called ligers.. and so many other animals, such as dolphin and whales, etc... even domestic cats and wild big cat had been successfully crossbread, its the same as with the plants ... new kind of plants and animals were appearing in the face of the earth.. with the helped of science and technology, i guess, why biogenesis has been proven, we are now creating a new kinds of species..

we have 98.5% of DNA sequences shared with chimp, among human, all human almost has the same DNA, small fraction that makes our DNA different from others is 99.9%, human and mice is 60%.

its interesting to see their photos...

will get some photos...

woofers · May 2006

Ligers and other crossbreeds are sterile, thus they do not qualify as a species.

loc0 · May 2006

Looking to classify yourself apart from the "dimmer" members of humanity?

Jaywalker · May 2006

try to google "brain size intelligence race" and you'll find some very disturbing results.

hotchillipepper · May 2006

woofers wrote:

Ligers and other crossbreeds are sterile, thus they do not qualify as a species.

huh?

where did you get that? if a man is sterile, he is not species? and nowadays, with the help of stem cell research- IVF, thousands of couple are having their own kids even they are sterile.

do you know why male animals produce millions of ***** cell? to give them the best possible chance of success.

before civilizations, when it fertilized an egg, do you know the success rate to become a fetus? and do you know the success rate of giving birth?

why do animals produce hundreds of eggs, and only few big animals give birth to single offspring at one time.

and Do you know that survival of the fittest starts just before the fertilization.

next law of biogenesis....

micketymoc · May 2006

f.d.o., let's rephrase your first premise - that there "should" be multiple human species. I think this was true until the neanderthals died out - humans and h. neanderthalensis did coexist until our ancestors () outcompeted them. Since this happened relatively recently, we (the surviving species) haven't had the chance to branch out into new species. And given current circumstances, probably never will: you need with no chance of reproducing with each other to create a new species over time.

Anyway, I found the best response to your question from . Let me quote the relevant passage.

"...When geneticists had invented more precise ways to compare DNA, they would find that the variability had found among his fruit flies was the rule, not an exception. Among humans, for example, many biologists once thought that races carried dramatically different sets of genes. Some even went so far to claim that they were separate species. But research on human genetics shows that these old ideas were wrong. 'The biological notion that we used to have of races is not compatible with the reality of the genetics that we're finding today,' says Marcus Feldman, a geneticist at Stanford University.

"Out of 30,000 or so genes in the human genome, an estimated 6,000 genes exist as different versions (known as alleles). The distinctions that we conventionally use to divide the species into races - skin color, hair, and the shape of faces - are controlled by only a few genes. The vast majority of variable genes do not respect so-called racial boundaries. There is far more variability within any given population of humans than between populations. {interestingly, there is over this figure.}If all the humans on earth were wiped out except a single tribe in a remote New Guinea valley, the survivors would still preserve 85% of the genetic variability of our entire species."

la_flash · May 2006

hotchillipepper wrote:

where did you get that? if a man is sterile, he is not species? and nowadays, with the help of stem cell research- IVF, thousands of couple are having their own kids even they are sterile.

I think what he/she meant was for any specie to survive, it must be
capable of reproduction (sexual or assexual). Since Ligers and other
crossbreeds are sterile, they won't survive (without any intervention),
therefore can not be classified as a specie.

Just curious:
a. Why crossbreeds become sterile? What in the genetic make-up of
the product contribute to this?
b. Is this also true in Kingdom Plantaea?

Sorry... OFF TOPIC.

hotchillipepper · May 2006

complex species or/all animals started the same during fertilization..

-the process of fertilization of one ***** cell( out of millions) and ovum-one female egg are the same in all animals, whether they are fish, reptiles, birds and big or small mammals.

all animal embryos are microscopic size like a size of a pin head / or like bacteria.

look carefully ....

I -1st stage.. they all quite the same...

II- they start changing their shapes and sizes.

IIi fully developed into unique species

Lucca Yamazaki · May 2006

Give it some time, after the Atomic Wars. We'll have humans, mutants, ghouls, and people who run around the wasteland in blue jumpsuits with yellow prints.

hotchillipepper · May 2006

la_flash wrote:

Just curious:
a. Why crossbreeds become sterile? What in the genetic make-up of
the product contribute to this?

Sorry... OFF TOPIC.

check out for the study of genetically engineered obese mouse, they produced a new generation of fat mice too...

DNA is one of the best discovery that happened in 20th, in the future, next generations will be free of any disease that they can possibly inherited from their parents and plenty more...

faaip_de_oiad · May 2006

micketymoc: Yeah, the Neanderthals were a subspecies, but what makes them different from the Homo sapiens sapiens?

Im sure the differences between neanderthalensis and Homo sapiens sapiens are a lot more neglible than the variety that we could see in humans today.

I heard about scientists crossbreeding a zebra and another equine to produce a quagga like animal (an extinct species). I heard it was sterile.

Oneiros · May 2006

la_flash wrote:

I think what he/she meant was for any specie to survive, it must be capable of reproduction (sexual or assexual). Since Ligers and other
crossbreeds are sterile, they won't survive (without any intervention),
therefore can not be classified as a specie.

Just curious:
a. Why crossbreeds become sterile? What in the genetic make-up of
the product contribute to this?
b. Is this also true in Kingdom Plantaea?

Yup, as has been pointed out there is an increasing trend to de-emphasize morphological uniformity as a criteria for delineating species with a shift towards genetically based criterion based on the viability (i.e. ability to reproduce) of offspring. One of the more recognizable proponent of the latter criteria is Ernst Mayr who gave the definition of species as:

groups of interbreeding natural populations that are reproductively isolated from other such groups

.

And he elaborates further on his usage of the term "reproductive isolation" by stating that in his usage they only include:

biological properties of individuals which prevent the interbreeding [fusion] of populations

As for question A:

A horse has 64 chromosomes and a donkey has 62, so a mule is left with 63, an uneven number which cannot divide into chromosome pairs. This should make a mule unable to reproduce.

So presumably the same happens in the Liger's case (i.e. uneven/odd number of chromosomes). Pero ang nakakapagtaka nga dun sa link na binigay ko e nagkaanak nga daw yung mule... I'd guess a possible explanation e nagkaroon ng chromosomal aberration noong gamete formation/meiosis yung nanay na mule...

Malay ko sa B pero parang may namention nga dati yung prof ko sa bio na hybridization is more prevalent in plants (malay ko kung bakit, tulog yata ako nung binigay nya explanation e). :(

micketymoc · May 2006

hotchillipepper wrote:

complex species or/all animals started the same during fertilization..

-the process of fertilization of one ***** cell( out of millions) and ovum-one female egg are the same in all animals, whether they are fish, reptiles, birds and big or small mammals.

all animal embryos are microscopic size like a size of a pin head / or like bacteria.

look carefully ....

I -1st stage.. they all quite the same...

II- they start changing their shapes and sizes.

IIi fully developed into unique species

Don't mean to be a KJ, but here's an old biology saying: "Ontogeny does not recapitulate phylogeny". (Click on article for definitions of "ontogeny" and "phylogeny".)

Ernst Haeckel, who first saw the similarities between embryos of different species and to explain it, actually over-generalized. Human embryos don't recapitulate mature fish forms, or mature amphibian forms. The much bandied-about "gill slits" in human embryos are actually just invaginations that never assume the function of real gills in any form.

faaip_de_oiad · May 2006

Kingdom Plantaea?!

what a poseur.

specie?!

wow. ang talino mo naman.

faaip_de_oiad · May 2006

micketymoc wrote:

Don't mean to be a KJ, but here's an old biology saying: "Ontogeny does not recapitulate phylogeny". (Click on article for definitions of "ontogeny" and "phylogeny".)

Ernst Haeckel, who first saw the similarities between embryos of different species and formulated a theory to explain it, actually over-generalized. Human embryos don't recapitulate mature fish forms, or mature amphibian forms. The much bandied-about "gill slits" in human embryos are actually just invaginations that never assume the function of real gills in any form.

I heard that adage almost every single lecture day a few sems back.

The gill slits (I think) are compared to the presumptive gill slits of other animals - I've never heard anyone claim that they had the genetic propensity to turn into functional respiratory gills. I dunno, it was taught that way to us.

Oneiros · May 2006

Lucca Yamazaki wrote:

Give it some time, after the Atomic Wars. We'll have humans, mutants, ghouls, and people who run around the wasteland in blue jumpsuits with yellow prints.

Don't forget the two-headed brahmins, oversized rats and the sentient man-sized lizards.

Coincidentally, this reminds me that I should be going back to stealing everything not bolted down in Vault City... Tsk, I sure wish there was a mission to assassinate that genocidal ***** who calls herself First Citizen.

Ischaramoochie · May 2006

aye, just don't forget yer water chips

micketymoc · May 2006

faaip_de_oiad wrote:

I heard that adage almost every single lecture day a few sems back.

The gill slits (I think) are compared to the presumptive gill slits of other animals - I've never heard anyone claim that they had the genetic propensity to turn into functional respiratory gills. I dunno, it was taught that way to us.

You tell me. Ever since RoT ignited my for books on evolution (thanks xtian fundies - you're good for something after all!), that phrase keeps popping up every few pages.

I think it's 'cause Haeckel's illustrations seem so compelling, that biologists need to keep stressing how misleading "ontogeny recapitulates phylogeny" can be.