Define 'species'

[mark kennedy]

I have been told a number of times by evolutionists that Darwin was wrong about some things but made groundbreaking progress in natural history. Just kind of curious how the modern evolutionist feels about Darwin refusing to define his central term. I asked this in the formal debate forum and I am still awaiting a response so I thought I would bring it up here to see what kind of a response I'd get.

" This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species. " (Darwin's conclusion from Origin of Species)

So was ole flycatcher right or wrong about the essense of the species being undiscoverable? Just curious what your thougts are.

 

[Mekkala]

I have been told a number of times by evolutionists that Darwin was wrong about some things but made groundbreaking progress in natural history. Just kind of curious how the modern evolutionist feels about Darwin refusing to define his central term. I asked this in the formal debate forum and I am still awaiting a response so I thought I would bring it up here to see what kind of a response I'd get.

" This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species. " (Darwin's conclusion from Origin of Species)

So was ole flycatcher right or wrong about the essense of the species being undiscoverable? Just curious what your thougts are.

Well, we use the word "species" to refer to useful distinctions between communities of organisms. These distinctions are useful in the sense that they aid classification -- but as far as the lack of any "essence" of a species, Darwin was correct. All organisms are just that -- biological lifeforms with various sets of chromosomes. It so happens that any given lifeform tends to share large portions of DNA with many other lifeforms, and for our convenience, we group those with the most similar DNA code under the label of "species". Ultimately, it's an artificial division that exists as a well-defined classification only in the minds of human scientists.

 

[Physics_guy]

Define species in what sense? For sexually reproducing animals? For asexually reproducing organisms? Do we allow hybridization?

See, the point Darwin made and is still very true today, is that there is no fundamental all applicable dividing line between groups of organisms. We use the term species because it helps for classification, that is all. Strangely enough, evolution predicts this.

BTW - are chimps and humans different species Mark? I would bet that you and most others would say that they were. Now, what would happen to your religious beliefs if someone showed that chimps and humans could hybridize? I am not saying that they could, but it certainly is a possibility.

 

[Phred]

Perhaps while we're at this you could define "kind"?

 

[Mekkala]

Define species in what sense? For sexually reproducing animals? For asexually reproducing organisms? Do we allow hybridization?

See, the point Darwin made and is still very true today, is that there is no fundamental all applicable dividing line between groups of organisms. We use the term species because it helps for classification, that is all. Strangely enough, evolution predicts this.

BTW - are chimps and humans different species Mark? I would bet that you and most others would say that they were. Now, what would happen to your religious beliefs if someone showed that chimps and humans could hybridize? I am not saying that they could, but it certainly is a possibility.

I would consider it a very distinct possibility -- but I would also consider it a great cruelty to bring such a hybrid child into the world. The child would be neither chimp nor human, yet most likely intelligent enough to be aware of this and feel not without a community, or without a social life, or without a nation, but without even a species to call his own. For less intelligent creatures who don't really understand this, it's not so bad. But for a half-chimp, half-human child, I think it could very well be horribly damaging.

 

[mark kennedy]

Well, we use the word "species" to refer to useful distinctions between communities of organisms. These distinctions are useful in the sense that they aid classification -- but as far as the lack of any "essence" of a species, Darwin was correct. All organisms are just that -- biological lifeforms with various sets of chromosomes. It so happens that any given lifeform tends to share large portions of DNA with many other lifeforms, and for our convenience, we group those with the most similar DNA code under the label of "species". Ultimately, it's an artificial division that exists as a well-defined classification only in the minds of human scientists.

I understand what you are saying about taxonomy but it seems odd that someone would argue that we will eventually discover the line of descent for our species without ever actually defining the term. Ernst Mayr said once that the term generally refers to organisms the can reproduce amonst theirselves. I think the term has been modified somewhat due to things like ring species where due to geologic distance creatures over generation over time can't reproduce together.

What has me puzzled the most is that microevolution is changes below the level of species, and macroevolution is changes above the level of specices. This seems like some pretty fuzzy logic to me and not what I would expect from scientists that pride themselves on having precise and meticulas systems of thought.

 

[Mekkala]

I understand what you are saying about taxonomy but it seems odd that someone would argue that we will eventually discover the line of descent for our species without ever actually defining the term. Ernst Mayr said once that the term generally refers to organisms the can reproduce amonst theirselves. I think the term has been modified somewhat due to things like ring species where due to geologic distance creatures over generation over time can't reproduce together.

What has me puzzled the most is that microevolution is changes below the level of species, and macroevolution is changes above the level of specices. This seems like some pretty fuzzy logic to me and not what I would expect from scientists that pride themselves on having precise and meticulas systems of thought.

There is no "essence" of a species, but the term still has a definition, mark. So far as I know, Darwin never said the word couldn't be defined, but just that it has no discoverable "essence". The general community of organisms that we have defined as "human" do have a line of ancestry that we could discover.

 

[notto]

I understand what you are saying about taxonomy but it seems odd that someone would argue that we will eventually discover the line of descent for our species without ever actually defining the term. Ernst Mayr said once that the term generally refers to organisms the can reproduce amonst theirselves. I think the term has been modified somewhat due to things like ring species where due to geologic distance creatures over generation over time can't reproduce together.

What has me puzzled the most is that microevolution is changes below the level of species, and macroevolution is changes above the level of specices. This seems like some pretty fuzzy logic to me and not what I would expect from scientists that pride themselves on having precise and meticulas systems of thought.

Then you must agree that the term 'kind' is as fuzzy as well, right?

 

[mark kennedy]

There is no "essence" of a species, but the term still has a definition, mark. So far as I know, Darwin never said the word couldn't be defined, but just that it has no discoverable "essence". The general community of organisms that we have defined as "human" do have a line of ancestry that we could discover.

Well if you look closely at the line of descent it is puzzling how at one point the lineage splits from Astralopithecus gari into two discernably different species and the merges later to form Homo rudolfensis and Homo habilis. Then Homorergaster emerges only to split down two lines of descent. Now classication of species are central to the cladistics (charting family trees) so how do we know when there is macroevolution when we don't have a benchmark for species?

By the way the word 'kind' is a general term that probably refers to something more like family and genus. Even in evolution these levels of classification are immutable in the sense the no amont of evolution breaches these barriors. This in keeping with the Genesis account and actually makes the universal common ancestory model questionable.

 

[mark kennedy]

There is no "essence" of a species, but the term still has a definition, mark. So far as I know, Darwin never said the word couldn't be defined, but just that it has no discoverable "essence". The general community of organisms that we have defined as "human" do have a line of ancestry that we could discover.

Well and good, what is the definition for species? I know the textbook definition is the group of organisms that breed only among themselves. It seems that the essense of a term like speciation would have to be comprehensive to determine if an alltogether new kind of species has indeed emerged.

 

[Phred]

I understand what you are saying about taxonomy but it seems odd that someone would argue that we will eventually discover the line of descent for our species without ever actually defining the term. Ernst Mayr said once that the term generally refers to organisms the can reproduce amonst theirselves. I think the term has been modified somewhat due to things like ring species where due to geologic distance creatures over generation over time can't reproduce together.

What has me puzzled the most is that microevolution is changes below the level of species, and macroevolution is changes above the level of specices. This seems like some pretty fuzzy logic to me and not what I would expect from scientists that pride themselves on having precise and meticulas systems of thought.

It's all evolution Mark. Small changes add up to large ones. Eventually, one population of creatures can no longer interbreed with another population even though they share a common ancestor. Macro and micro evolution aren't really scientific processes, they're just descriptors of a single process.

I've read articles that suggest creationists coined those terms since they had to allow for some sort of evolution taking place. Dunno if I accept that one or not...

 

[Mekkala]

By the way the word 'kind' is a general term that probably refers to something more like family and genus. Even in evolution these levels of classification are immutable in the sense the no amont of evolution breaches these barriors. This in keeping with the Genesis account and actually makes the universal common ancestory model questionable.

That's a pretty serious misconception, mark. Granted, no species will evolve from one family into another existing one -- but that's only because families (and other biological classifications) are based on the grouping of descent. It's not possible for a biological line to obtain ancestors it didn't previously have. That's obvious simply from the very nature of reproduction. However, it is not a "barrier" as such. This does not limit the possible changes in alleles within a population. New genuses and families and species can be created. It's just not possible for a species to move from one existing group into another existing group by evolution -- instead, they may evolve into a new family, genus, order, etc., that did not previously exist.

 

[mark kennedy]

It's all evolution Mark. Small changes add up to large ones. Eventually, one population of creatures can no longer interbreed with another population even though they share a common ancestor. Macro and micro evolution aren't really scientific processes, they're just descriptors of a single process.

I've read articles that suggest creationists coined those terms since they had to allow for some sort of evolution taking place. Dunno if I accept that one or not...

But how do they add up? We have dominant and recessive genes in 3:1 ratios and there are times when no evolution actually occures and we have a mathmatical formula for that. So what happens to the ration of dominant and recessive genes since somehow the dominant genes don't keep the inheritance of traits at the normal ratio?

 

[mark kennedy]

That's a pretty serious misconception, mark. Granted, no species will evolve from one family into another existing one -- but that's only because families (and other biological classifications) are based on the grouping of descent. It's not possible for a biological line to obtain ancestors it didn't previously have. That's obvious simply from the very nature of reproduction. However, it is not a "barrier" as such. This does not limit the possible changes in alleles within a population. New genuses and families and species can be created. It's just not possible for a species to move from one existing group into another existing group by evolution -- instead, they may evolve into a new family, genus, order, etc., that did not previously exist.

Evolution does not reverse itself according to popular convention. So the descent is traced back to an all together ancestor and one of the things that is supposed to have caused this is the environment the organism finds itself in. Let me ask you this, if it was demonstrated that the earths conditions have not changed dramaticlly since, say, the time of homo hablis how would you account for the evolution from early transitionals to modern human?

 

[Mekkala]

Evolution does not reverse itself according to popular convention. So the descent is traced back to an all together ancestor and one of the things that is supposed to have caused this is the environment the organism finds itself in. Let me ask you this, if it was demonstrated that the earths conditions have not changed dramaticlly since, say, the time of homo hablis how would you account for the evolution from early transitionals to modern human?

Um... I wouldn't have any trouble accounting for it at all. Why would I?

I'll tell you why -- I would have trouble if the strawman you're presenting had anything to do with evolution. Fortunately, it doesn't. In fact, there's no need for major or catastrophic environmental changes for evolution to occur. All it takes is a infinitesimal gain in survival ability for a mutation to spread throughout a population. An increased survival capacity of a fraction of a hundredth of a percent is enough for evolution to occur. You can verify this simply by writing a very simple simulation of reproductive activity -- you don't even need to look at the fossil record.

 

[mark kennedy]

Um... I wouldn't have any trouble accounting for it at all. Why would I?

I'll tell you why -- I would have trouble if the strawman you're presenting had anything to do with evolution. Fortunately, it doesn't. In fact, there's no need for major or catastrophic environmental changes for evolution to occur. All it takes is a infinitesimal gain in survival ability for a mutation to spread throughout a population. An increased survival capacity of a fraction of a hundredth of a percent is enough for evolution to occur. You can verify this simply by writing a very simple simulation of reproductive activity -- you don't even need to look at the fossil record.

I didn't say catastrophic what I was saying was directly related to evolutionary theory, specificlly, design pressure. Most of the reasons that species change is do to changes in the environment...I don't have the slightest clue why you think this is a strawman argument.

An increase in the survival capacity of a fraction of a hundredth of a percent is not macroevolution, thats microevolution, maybe. Whats more you never told me how the changes are accumulated, we have a formula for equilibrium, wheres the one for evolution?

 

[Mekkala]

I didn't say catastrophic what I was saying was directly related to evolutionary theory, specificlly, design pressure. Most of the reasons that species change is do to changes in the environment...I don't have the slightest clue why you think this is a strawman argument.

You asked what it would do to my knowledge of evolution if it were known that the environment had not changed dramatically. My point is that no dramatic change or pressure is necessary. In fact, even when there is no change at all, there is environmental pressure. Any species that is not utterly invulnerable experiences enviromental pressure -- and if even one hundred-thousandth of a population die before childbearing age, that population is under environmental pressures that will bring about evolution.

Of course you have no clue why I think it's a strawman argument -- you have no clue because you learned these arguments from creationists who build strawmen for a living. It's not your strawman, but someone else's; and then when you present it, you get attacked for it -- perhaps unfairly, since you honestly believed it to be a good argument, but you can hardly expect to present deceitful information, whatever the source, and not get attacked.

Mark, I think you might be astounded at what you would find if you went to the trouble of reading peer-reviewed scientific papers on the subjects that the creationist arguments you've learned address. Do you know how and why I left the creationist camp for the evolution camp (this was long before I left Christianity, by the way)?

Because I'd noticed that the arguments I used from A Beka and Kent Hovind and Bob Jones weren't getting many results. They generally got debunked pretty easily. I decided to check out all the scientific data in support of these arguments (data that I had no doubt was out there) so that I would truly understand what the arguments were saying and be able to answer objections to those arguments better. To my undying wonder, I discovered in my search that all the data -- even the data used by creationists -- supports evolution and none of it supports creationism. This was by doing my own research into scientific discoveries of the past century, not by reading creationism websites or evolution websites, or by listening to arguments for or against evolution.

So again, may I suggest that you take the same path that I did? You may not come to the same conclusion that I did (although honestly, I can't for the life of me fathom how you wouldn't, if you looked at all the data that I've seen), but at least you can say that you truly know what you're talking about. At least you can avoid saying things like what I just chewed you out for -- and you can earn or lose respect on your own merits, instead of seeing your credibility cut out from under you through no fault of your own, because you used something you learned from a self-proclaimed "creation scientist" who is out to win souls at all costs -- even if it means lying through their teeth.

An increase in the survival capacity of a fraction of a hundredth of a percent is not macroevolution, thats microevolution, maybe. Whats more you never told me how the changes are accumulated, we have a formula for equilibrium, wheres the one for evolution?

Again, you misunderstand.

Say we have Mutation A that appears in a single individual in a population. If A gives that individual a survival advantage of a fraction of a hundredth of a percent over the other individuals in that population, then it is only a matter of time before virtually every individual in the population has the mutation. Do you see what I'm saying? Thus, no catastrophic or major environmental change is necessary for evolution to happen. As long as survival is a needed ability (that is, as long as organisms die before childbearing age), the necessary pressures exist to make evolution happen. This is so even when the environment is completely static and unchanging.

 

[Ishmael Borg]

" This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species. " (Darwin's conclusion from Origin of Species)

So was ole flycatcher right or wrong about the essense of the species being undiscoverable? Just curious what your thougts are.

Hi Mark.

I think Darwin meant that since the concept of species no longer involved groups of immutable organisms, pinning down a list of criteria for the term made little sense. The definitions we use today are serviceable. "Essence" is a funny word here (I know it was Darwin's choice of words). I agree with him that this essence is undiscoverable.

-Ish

 

[mark kennedy]

Strangely the first substantive post and I have to go, but I did want to straighten something out. I did not learn my arguments from creationists. I learned them from evolutionists and some of the things I learned about how we judge the historicity of an event. I will be back to address the above post, you can count on that.

 

[lucaspa]

I have been told a number of times by evolutionists that Darwin was wrong about some things but made groundbreaking progress in natural history. Just kind of curious how the modern evolutionist feels about Darwin refusing to define his central term. I asked this in the formal debate forum and I am still awaiting a response so I thought I would bring it up here to see what kind of a response I'd get.

" This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species. " (Darwin's conclusion from Origin of Species)

So was ole flycatcher right or wrong about the essense of the species being undiscoverable? Just curious what your thougts are.

Darwin was referring to creationism when he talked about "essence of the term species". After all, if species are separate creations, as was believed in Darwin's day, then it should have been possible to find the precies definition of species. Today the same trouble plagues creationism in trying to define "kinds" (since both ICR and AiG have conceded evolution by admitting to speciation). In the 1982 Arkansas trial, one poor creationist witness had to confess that, after 25 years of studying turtles, he could not decide if they were one kind or, if they were more than one kind, how many kinds of turtles they were and which turtles belonged to each kind! What a waste of a life.

So... as Darwin meant the quote you took out of context, he was correct.

However, the whole quote is:

"Hereafter we shall be compelled to acknowledge that the only distinction between species and well-marked varieties is, that the latter are known, or believed, to be connected at the present day by intermediate gradations whereas species were formerly thus connected. Hence, without rejecting the consideration of the present existence of intermediate gradations between any two forms, we shall be led to weigh more carefully and to value higher the actual amount of difference between them. It is quite possible that forms now generally acknowledged to be merely varieties may hereafter be thought worthy of specific names; and in this case scientific and common language will come into accordance. In short, we shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations made for convenience. This may not be a cheering prospect; but we shall at least be freed from the vain search for the undiscovered and undiscoverable essence of the term species."

Species among multicellular life have biological reality; they are not merely artificial combinations. However, at unicellular life, that is how species are treated. So Darwin was right and wrong.

Notice, that if evolution is true, and species do transform to other species, then a precise definition of species is impossible. No matter what definition you come up with, you will always find a population in the process of transformation that is going to fall in the cracks of the definition such that you are not going to be able to decide whether there is one species or two.

So, the lack of a precise definition of species is actually very powerful support for the truth of evolution.