No, that's OK! If each one is a new species, where are the transitionals?
"I see a group of nice still pictures there. Tell me, however, which one shows the alleged transition?"
Posted on 08/24/2006 6:54:24 AM PDT by PatrickHenry
Scientists at Texas Tech University argue that defining mammalian species based on genetics will result in the recognition of many more species than previously thought present. This has profound implications for our knowledge of biodiversity and issues based on it, such as conservation, ecology, and understanding evolution. Their study is published in the latest Journal of Mammalogy.
The classical definition of species was proposed by Ernst Mayr in 1942, defining it as reproductively isolated groups of organisms. According to this study, the problem with applying this concept is that it is hard to observe mating and to know whether there is interbreeding between populations and thus creation of hybrid species. Traditionally, species have been recognized based on physical characteristics, although it has been assumed that species differences are inherited and thereby reflect genetic differences.
Study researchers Robert Baker and Robert Bradley define “species” based on genetic data. The new definition distinguishes species that are genetically isolated from one another. Baker and Bradley’s genetic species concept also differs from the phylogenetic species concept proposed by Joel Cracraft in 1989 by emphasizing genetic isolation and protection of the integrity of the gene pool.
New molecular techniques for sequencing genes provide far greater resolution than was previously available. They also allow researchers to quantify problems in understanding the process of speciation. Using genetic data, it is now possible to distinguish species that are morphologically similar — those known as cryptic species. It is also possible to identify species that hybridize but have gene pools that are protected from one another.
The result of using genetic data is that species can be identified that cannot be distinguished using other methods. Baker and Bradley point out that this means there are doubtless many more species than previously thought. They hypothesize that there are 2,000 more mammalian species than are currently recognized.
According to the authors, this means that we will need to rethink the nature of speciation in mammals, barriers that evolve to produce genetic isolation between species, and how diverse mammals are, as well as other species-based issues such as those relating to conservation and zoonoses, communicable diseases from animals to humans.
To read the entire study, click here. SPECIATION IN MAMMALS AND THE GENETIC SPECIES CONCEPT (PDF file, 20 pages long)
|
As I read the the original definition stands and the hew material makes it easier to identify reproductive isolates.
It's still a matter of them as can't interbreed are different species, just a better way to determine "can't interbreed"
In zoolological classification, there are "lumpers" and "Splitters". Lumpers tend to disregard minor differences between animals and lump them into the same classification. Splitters try to classify every minor variation as a new species. These guys are the ultimate splitters, potentially claiming any genetic variation as a different organism.
I prefer the functional approach to speciation. It they can mate and produce fertile offspring, they are the same species.
Let's see. Twenty pages of fairly dense science writing. I expect the first troll to denounce it within three minutes.
Now back to reading...
In re; "Everything is blasphemy to somebody."
Offense, like beauty, lies in the eye of the beholder.
For instance, I am offended by the association of conservatism with religion and with fundamentalism and with anti-evolution.
Personally, I am offended by folks who add fruity concoctions to gin and call it a Martini.
We define a genetic species as a group of genetically compatible interbreeding natural populations that is genetically isolated from other such groups. This focus on genetic isolation rather than reproductive isolation distinguishes the Genetic Species Concept from the Biological Species Concept. Recognition of species that are genetically isolated (but not reproductively isolated) results in an enhanced understanding of biodiversity and the nature of speciation as well as speciation-based issues and evolution of mammals.I haven't digested the article yet, but this seems to be a whole new concept.
Greater resolution equals reductio ad absurdium.
Nice idea, but not useful for day-to-day biological research.
I haven't digested it either, not that fast!
Still, all I'm seeing that's new-ish is an elaboration of crypto-species and I'm not sure they've actually defined a genetic boundary there. I expect we'll get there eventually though.
According to this proposed definition, my distant cousins in Australia may now be a different species from me. Well, it's true that we're so isolated we may never interbreed, but what's the point of defining us as different species?
Either that or they could scrap the whole mess, which would be fine by me!
They are defining transitionals as new species.
Evil, evil, bad, bad... Everyone knows there are no transitionals, therefore according to the authors there are no species.
Yes, we are one with the microbe. We are one with the monkey.
We are all Brothers in Darwin.
(Gimme a banana).
Ah, the light dawns. I certainly hope that these transitionals will be exterminated as quickly as they can be identified. We must maintain the purity of creation, and not allow it to be polluted by anything that might otherwise evolve.
You are part of the continuum. You are a transitional. You will be assimilated into the Great Breast of Darwin.
Beware the knock on your door at 2 AM.
Beware the CreoPolizei.
I weep for you, my Brother in Darwin - Huggy, huggy (ptui!).
All animals are equal, but some are more equal than others.
We are dead.
Prepare for your demise.......
The only escape from being a transitional is to be a dead end. Extinction is our only hope. Preserve the essence of your genetic purity. Cease breeding!
this is my kinda Species:
http://www.imdb.com/name/nm0000449/
I prefer the "if it looks different enough, it is a species" method. That's what they (have to) use on fossils.
No, that's OK! If each one is a new species, where are the transitionals?
"I see a group of nice still pictures there. Tell me, however, which one shows the alleged transition?"
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.