What is your definition of a species?

[juvenissun]

gray areas always plague men's definitions of natural phenomena. look at planets, even something as supposedly basic as gender has grey areas.

Of course, this is the nature of science. I am not picking on that.

At least astronomers ARE working on the definition of planet. Where is the effort among evolutionists to work out a "better" definition of species? Besides, this definition is much much more critical to evolution than that of a planet to astronomy. In a sense, it is one of the fundamental concepts of evolution. It could not be left so vaguely and so inconsistent as such.

 

[juvenissun]

First, there is no single "family of bacteria." Bacteria constitute many families, each with its own definition. You seem to be confusing the definition of a taxon (whatever particular family you may have in mind) with the definition of a rank: family.

More over, if one critical term could mean a few things, then the process involved, which is evolution, could also have a few different meanings. Then I can only see a mess in this "well-established" model.

Well, you'd have to attempt to show this to be true before I would care to refute it. It just isn't worth my time to bother with more unsubstantiated claims.

I understand what you mean. I could not show you more than what I said.

However, just read again on your explanation of bacteria "family". I don't quite understand it, but the only thing I can see is the inconsistency on the use of the word "family". That is an example of the mess I referred to in the study of evolution.

 

[corvus_corax]

I am always happy.

Thats great to hear (seriously)
Ive recently reached that point myself

If you admitted that evolution is only a model, then I am more interested in debating you regards to the model.

But that's the point....the Scientific Theory of Evolution IS a model, and one that best explains the current diversity of species (the fact of evolution) on this planet.
Just like the Scientific Theories of Gravity are models that best explain the fact of what we call gravity.

In this forum, I seldom promote creation explicitly. My goal is to defeat evolution.

See? That's exactly why I appreciate you
YOU, unlike most creationists, are not (according to your own statement) attempting to create a false dichotomy.
You (and most creationists, they just won't admit it) are all about trying to "defeat" or "disprove" or "falsify" evolution.
You have been honest enough to admit the actual POINT of Creationism. Good for you
I don't think you'll succeed, but at least YOU are an honest Creationist (in this specific regard)

And that is why I've sigged your statement...to remind Creationists of what their ACTUAL goal is (despite their conflation otherwise).

 

[Washington]

However, just read again on your explanation of bacteria "family". I don't quite understand it, but the only thing I can see is the inconsistency on the use of the word "family". That is an example of the mess I referred to in the study of evolution.

To clarify:

The seven ranks of Domain, Kingdom/Division, Phylum, Class, Order, Family, and Genus, plus all the intermediate ranks that have been plugged in between at various times, have no specific definitions other than as hierarchical levels that function to incorporate the levels below them. Thus the rank of Class functions to include all organism that are grouped below it in Orders, Families, Genera, and Species. This system of classification is pretty much a mandatory one that demands that characteristics be established, as much as practicable, to define the taxons of each. HOWEVER, the ranks themselves are not defined in terms of biological constructs. The rank of family is not defined by any biological characteristics. It's only a level like the other six. E. O. Wilson said it well when he defined the family rank as "a group genera." (post #46 ) That's all the rank of family is. And that's all the Class rank is: a group of families; and so forth. Nothing more!

Now, the taxons that make up each rank is a different thing. Within a family, say, each taxon of that family has specific characteristics that govern the inclusion of its genera. This allows the family taxon Felidae to admit all genera of cat "type" animals and exclude the genera of dog "type" animals, which meet the characteristics that define the Canidae family.

So it doesn't matter what kind of disputes go on at the species level; trying to establish what defines a species, or why. By the time an organism is ready to be classified into a family it's a moot point. The only element of concern is what the characteristics of its genus are, which will determine the family it belongs to.

And, as my be apparent by now, the higher one goes up the hierarchical ladder the more "gross" the qualifying characteristics become. Those characteristics that define the phylum chordata (essentially animals with backbones) are very, very different from those that define the phylum echinodermata (animals with pentaradial symmetry--eg. starfish).
However, not all taxons have established defining characteristics, This happens when an organism is so unique that it is pointless to establish any. The ginko tree is a good example. It belongs to the class Gymnosperma, order Gingoales, family Ginkoaceae, genus Ginko, and species biloba. It is the only species in the entire order, which means there's no useful purpose in selecting specific family or genus characteristics. So, there are none, although the names of its family and genus have been created.

 

[Tomk80]

If so, why didn't evolutionist change or limit the use of the word species? It is obviously a BIG flaw in the structure of evolution theory.

No, it is expected of evolution theory is true. If evolution is true, we expect the species distinction to blur. Otherwise, new species would not be able to naturally evolve from old ones.

And the confusion HAS to extend to the terms used higher ranks. For example, how do you define the "family" of bacteria? Is there such definition exist? More over, if one critical term could mean a few things, then the process involved, which is evolution, could also have a few different meanings. Then I can only see a mess in this "well-established" model.

As I said before in another thread, these definitions are largely arbitrary. This is because these categories do not describe naturally existing phenomena but arbitrary names for a certain level of grouping.

In nature, species would be the only construct representing a reflection of something happening in nature. And given nature, there will be points where this distinction between groups will blur.

And that is exactly the problem with kinds. If "kinds" would really exist, instead of being an arbitrary construct, we should be able to give a distinct definition to it. We should be able to objectively determine whether something is of one "kind" or another. We can't, because the concept of "kinds" is not an accurate reflection of what happens in nature. It's a nonsense concept.

 

[CACTUSJACKmankin]

Of course, this is the nature of science. I am not picking on that.

At least astronomers ARE working on the definition of planet. Where is the effort among evolutionists to work out a "better" definition of species? Besides, this definition is much much more critical to evolution than that of a planet to astronomy. In a sense, it is one of the fundamental concepts of evolution. It could not be left so vaguely and so inconsistent as such.

just because you are unaware of the debate, doesnt mean it doesnt exists.
here is a list of several proposed definitions of species, each has its pros and cons:
http://en.wikipedia.org/wiki/Species#Definitions_of_species

 

[juvenissun]

To clarify:

The seven ranks of Domain, Kingdom/Division, Phylum, Class, Order, Family, and Genus, plus all the intermediate ranks that have been plugged in between at various times, have no specific definitions other than as hierarchical levels that function to incorporate the levels below them.

Thank you very much for taking time to educate. I don't have anything more to say about the classification at this time. I was exposed to this system at my middle school age and it frightened me ever since. I never touched them at later years. As you can imagine, my paleontology score on the GRE was extremely low. However, I was able to make it up by high scores on all other parts.

 

[Radagast]

Every once in a while one props up. IIRC there are 4 recorded cases of fertile female mules.

I stand corrected.

I'd be interested to hear how that works, genetically.

Look I am not looking up tons of hybrids.... try researching a little bit before trying to contribute (ie try wikipedia )

Well, you made the sweeping claim... maybe I could say the same to you.

Hybridisation is fairly common among plants (especially through tetraploidy), and most people can list examples (peppermint, triticale, loganberries). It is less common among animals, and I would think nowhere near as common as you suggest.

 

[Nooj]

Time is not a guarantee of speciation. Bacteria did not change much in the past 4 billion years.

I beg to differ, look outside your window. Every visible form of life that you see is descended from bacteria.

 

[Tomk80]

I stand corrected.

I'd be interested to hear how that works, genetically.

Wiki to the rescue:
Several female mules have produced offspring when mated with a purebred horse or donkey. Since 1527 there have been more than 60 documented cases of foals born to female mules around the world. There are no recorded cases of fertile mule stallions. Mules and Hinnies have 63 chromosomes that are a mixture of one from each parent. The different structure and number usually prevents the chromosomes from pairing up properly and creating successful embryos. In most fertile mule mares, the mare passes on a complete set of her maternal genes (i.e., from her horse/pony mother) to the foal; a female mule bred to a horse will therefore produce a 100% horse foal.