The
term “species” is surprisingly difficult to define. When asked,
most people offer a reproductive test; that is, creatures that can
reproduce naturally together and have fertile offspring are the same
species. Of course, this definition is not without a myriad of
exceptions. Wolves and dogs, for example, can mate and have fertile
offspring yet they are considered different species. So can bison
and cows, polar and grizzly bears, and dozens of other mammals.
Hybridization is ridiculously common in plants. All of these are
examples of different species mating so the ability to reproduce is
not a rigorous definition of a species. Neither can a reproductive
test be used to identify species of asexual organisms like bacteria.
Species
is an invented term, I understand that. And, in spite of the many
problems of defining it, I usually don't have a problem with the
word. However, in some cases, an exact meaning of the term is
necessary. I came across just such an instance the other day. On
FaceBook, someone posted an article
titled, Scientists
watch as a new species evolves before their eyes. From the
article:
Speciation,
the formation of new species through evolution, is not usually an
event you can directly observe. Organisms typically take many
generations to accumulate enough changes to diverge into new species;
it's a slow process. In fact, the difficulty of directly observing
speciation is a reason cited by skeptics of evolution for why they
have doubts.
¶But
biologists working at the University of California, San Diego, and at
Michigan State University, may have just put a rest to all of those
naysayers. They report to having witnessed the evolution of a new
species happen right before their eyes, in a simple laboratory flask
You
can see from this paragraph, the author of the article is suggesting
that the emergence of a new species (in the article, it's a new
species of a virus) is somehow evidence of evolution. If the rise of a new species is to be
used as an example of evolution, then yes, I'm going to ask what criteria are the scientists using to define a species? In this case, a reproductive test is not sufficient
since viruses are also asexual and cannot “mate” with the parent
population in any manner.
Did
you notice, too, how the author seems characterize critics of
evolution as people who deny speciation happens? He was very careful
not to use the word, “creationists,” but we all know that's who
he means. It's typical of evolutionists to make this straw man
argument. The reality is that most creationists don't deny
speciation. In fact, it's a critical part of young earth
creationism. God created animals according to “kinds.” Noah
took terrestrial animals on the ark in pairs of “kinds.” All
modern species are descended from these narrow groups. The 30+
species of modern cats are all descended from the 2 felines on the
ark, for example.
When
told that creationists accept speciation, evolutionists respond in
one of two ways. One way is to ridicule the creation model as a
type of “hyper-evolution” because the amount of diversification
that has occurred during the time since the Flood is much faster than
the slow, gradual process theorized by evolutionists. In a previous
post, I've discussed the claim that creationism
is a belief in hyper-evolution. It's also somewhat hypocritical
of them to criticize creationists for believing in rapid speciation
when they post articles like the one above talking about speciation
happening before their eyes – but never mind that now.
The
other way they respond is to throw out a red herring and ask the
creationist to define the term, “kind.” It's a red herring
because, whether or not a creationist can define the word, “kind,”
it doesn't excuse the evolution from having to define a species when
it's being used in the example above.
When
I was discussing the article above on FaceBook, one critic actually
said he couldn't respond to any of my points until I gave a precise
definition of “kind.” Really? I doubt that. I mean, there may
not be an iron clad definition of the word species but I understand
the term well enough to discuss it. I use the term frequently myself
and only ask for a rigorous definition when evolutionists try to
leverage “speciation” as evidence for their theory. Am I
supposed to believe that evolutionists can't understand the concept
of “kind” well enough to discuss it unless we give them an iron
clad definition first? Like I said, it's a red herring.
I've
discussed species
and kinds on my blog before. I might not be able to give a
rigorous definition of either but here are some practical
definitions. A species is a population of organisms that have enough
traits in common that they can be identified as belonging to the same
group. I admit, my definition may have a few difficulties but at
least it's rid of the need of a reproductive boundary. A kind is a
group of organisms originally created by God that would reproduce
organisms similar to themselves and includes all the varied species
descended from the original group. Maybe I could come up with a
better definition but, I daresay, this one is more precise than
nearly any definition of species that I've heard from evolutionists.
Think
about examples of species and kinds. Dogs, wolves, and coyotes can
breed together and have fertile offspring yet they are considered
different species. Because of their very different anatomies, Great
Danes can no longer reproduce with chihuahuas yet they are still
considered the same species. Evolutionists and creationists both
agree that all canine have descended from a common ancestor yet if
creationists call the members of the canine group a “kind,”
evolutionists act like they can't understand the term at all.
//RKBentley
scratches his head//
Evolutionists
play word games. They constantly conflate natural selection and
evolution. I talked in my
last post about how they casually use the word theory but harp on
creationists for calling evolution a theory. They claim
macroevolution is evolution above the species level but they can't
even define what a species is. When pressed for a definition of
species, they attempt to derail the conversation by asking
creationists to define a kind instead. I agree you can't have a
conversation with someone if there isn't a clear understand of the
terms being discussed. In the evolution/creation debate,
evolutionists aren't interested in discussion. I know they're not
stupid – they're just playing dumb. Conflate, equivocate,
obfuscate. That's the tactic of evolutionists.
4 comments:
Here is the most striking difference between "kinds" and "species." If humans share common ancestors with baboons and bass, species are temporary (even if we ignore extinction) and fuzzy categories: there must be intermediate forms in time, and often will be in space (e.g. "ring species" and cases where experts cannot agree whether two populations are separate species or merely separate subspecies). If special creation is true, then "kinds" must be fixed and immutable and (barring extinction) permanent. Evolution implies that there is a certain arbitrariness in all biological classifications (like naming the colors of a rainbow or setting legal ages to do various things, you're drawing lines on a continuum); creationism implies that one particular biological classification is an absolute fact -- changes in gene frequencies within a population cannot, no matter how much time or mutation or selection pressure is available, change the population into a different "kind."
This seems to imply that "kinds" ought to be recognizable, marked by distinct features that limit change and delineate them from other "kinds." One would think that if this were true, taxonomists would notice these features and use them, with the result that "kind" boundaries would in fact correlate to some particular Linnean rank (e.g. not just "roughly the equivalent of Linnean families," when they're not roughly the equivalent of Linnean genera or Linnean suborders or whatever). "Kinds" ought to be easier to define and recognize than species, if they actually exist.
I do find myself sharing your bafflement at viral speciation; indeed, it's been pointed out that "species" is a difficult category to apply even to indisputably living bacteria -- they don't mate, but they do share genetic material ("bacterial sex," although it's more like individual bacterial genes opting for free agency) across what are commonly treated like generic, family, order, or even class or kingdom lines.
On the other hand, surely you can see that it makes a difference whether something can undergo hundreds of generations in a day or one or two a year -- or one or two a decade. To get house cats and lions (very often treated as a single "kind" by YECs) within a few hundred years, tops, of the Flood (since they are depicted as quite separate species in ancient Egyptian art) is a very formidable task, and not the biggest degree of "change within kinds" that creationists have proposed; at least two young-earth creationists (Todd Woods and Kurt Wise) have proposed that the entire suborder Caniformia is a single "kind" derived from a single pair of ur-caniformes aboard the Ark. The Caniformia includes not merely dogs and foxes, but all bears and all seals, among other groups.
You raise the point that young-earth creationists don't dispute that speciation can occur. I note that, first, old-earth creationists do in fact often dispute that very point, and second, that some young-earth creationists have said they dispute it (the problem arises because of non-standard use, by creationists, of standard biological terms; I recall one creationist who claimed that woolly mammoths and African elephants were the same "species" -- surely he meant "kind"). Creationists' wilful failure to use terminology correctly engenders confusion in evolutionists who try to understand the creationist positions.
A species is a population of organisms that have enough traits in common that they can be identified as belonging to the same group.
Well, so it is. But that definition works equally well for "genus," "family," "order," "class," and "phylum" (a few centuries ago, people could tell that trilobite fossils belonged to the same general group as lobsters and insects -- though obviously they recognized that they weren't lobsters or locusts). For a single, general definition of "species" (biological sciences have thirty-odd different definitions, advanced by various scientists to deal with various problems, such as organisms that don't reproduce sexually and fossils that don't reproduce at all), I'm not sure that we've moved beyond John Ray's 17th century definition that species produce offspring of the same species (in which case, we can actually make sense of the claim that the evolved viruses were two new species -- neither was the sort of virus that the original ancestral virus would have caused E. coli to make new ones of).
I talked in my last post about how they casually use the word theory but harp on creationists for calling evolution a theory.
Well, yes, but the point is that creationists treat "theory" as some inferior rung on an epistemic ladder, and insist that common descent and adaption by natural selection need not be taken seriously until it reaches the rung of "fact" or "law." No matter how well-substantiated and comprehensively confirmed a theory is, it remains a theory -- calling something a "theory" is not a confession that it rests on guesswork or conjecture.
Steven J,
I agree that kinds are immutable. I don't agree that we should be able to easily recognize the members of a kind. If I remember correctly, bison and cows were not even considered the same genus before it was discovered they could hybridize. Technically, that would make them the same species. Certainly they're the same kind but their anatomical differences obscured that fact. I've also read about a psuedo killer whale and a dolphin that reproduced in captivity. I wouldn't be surprised if killer whales and dolphins were the same kind.
I believe defining a kind is fairly easy. Identifying all the members of a kind, not so much. The ability to reproduce across species is conclusive but not practical since we can't easily attempt to cross breed every single species. It's also impossible in the case of extinct creatures and asexual creatures. The inability to reproduce isn't necessarily a disqualifier either since sometimes anatomical differences have become so great that mating is no longer possible (as in very large and small dogs).
To your point on feline variation, I'm a little less incredulous than you. I believe house cats can reach sexual maturity in less than a year. They also have a few kittens in each litter. You'll recall I talked about the Russian experiment with the foxes. In that case, marked differences in appearance and behavior were achieved in only 8 generations. I believe remarkable changes in cats could occur in just one century.
Finally, if I had to assign an equivalent, secular term to kind, it would be close to family. Of course, it's not exactly the same as family. In the case of cats, I understand that some creationists put only members of the genus Panthera in the same kind. I don't necessarily agree but, hey, what's the big deal? It would be nice to have a tidy chart correctly categorizing every known organism but I'm not sure how it's absolutely necessary.
You didn't comment, though, on my point that many evolutionists seek a definition for kind only as an attempt to derail the conversation. Do you agree that evolutionists should at least understand the term well enough to have a discussion without demanding that we not only define the term but also that we be able to correctly categorize every creature of a kind?
Thank you for your comments. God bless!!
RKBentley
Okay, I agree with your point that asking you to define "kind" is a red herring in the particular instance noted. I'm not sure whether anyone has actually asked a creationist to do that in this particular instance, though. In a more general sense, though, saying that speciation and descent with modification is possible "within kinds" but not "between kinds" does indeed create an obligation to define "kinds," since otherwise this assertion has no discernible meaning.
With silver foxes, Belyaev started with a lot of foxes, and produced an animal that is roughly as different from the wild type of silver fox as, say, a collie is from a wolf. Starting with one breeding pair and producing dozens of different species within even a few hundred years is a rather more formidable problem (in that you have both much less genetic variety and far fewer opportunities to [a] generate new variety through mutation and [b] combine that new variety in various ways). I'm not saying that nothing can be done; apparently all pet hamsters on the planet are the descendants of a single pregnant female captured back in 1930, and quite a few obvious mutations (in coat color, etc.) have occurred and been spread among her descendants in less than a century. But, as I'd expect a creationist to note, they're all still Mesocricetus auratus.
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