Oolon Colluphid

Ref the swimming koalas, they would have had food on the way. The flood, which was anything up to five miles (and surely not less than one mile) deep as I indicated to David H in <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=58&t=000197&p=4" target="_blank">this thread</a>, would have undoubtedly wiped out just about all land plants. So if they survived the flood, Noah must have had them on board too. So the koalas simply took the eucalyptus with them. In little backpacks, presumably.

I’m also impressed by the tenacity of the hummingbirds who flew the Atlantic after the flood to get to South America.

Back to kinds... Randman, do you think that northern and southern leopard frogs (Rana pipiens complex) are the same kind? They are identical but for the fact that they cannot hybridise, apparently because their embryology is adapted to different temperatures. Yet they are linked via other members of the complex. If they are, then hybridisation is not a reliable guide to whether something is the same ‘kind’. So we have to use other criteria, such as morphology.

Where does that leave creatures that bridge groupings?

(To reuse something I’ve already written )...

For instance, take one example, snakes. New World garter snakes and water snakes (family Natricinae) are placed in separate genera, Thamnophis and Nerodia. But there is a spectrum of semiaquatic species, differing slightly in almost every possible respect, connecting them, such as the crayfish snakes (four species of Regina) and the Black Swampsnake Seminatrix pygaea. Cobras are put in a family of their own (Elapidae), but the fangs and poison glands that distinguish them are developed to varying degrees in a range of other snakes. Snakes as a group are distinguished from lizards by their lack of legs and certain features of their teeth and jawbones, yet among lizards there are many species with diminutive legs or none at all, and others with snake-like jaws (eg the 143 species of Amphisbaenians, skinks Scincidae, whiptails Teiidae, and flap-footed lizards Pygopodidae). Many ‘primitive’ snakes have remnants of a pelvic girdle and hind limbs, eg pythons and boas. One group of snakes, the blind snakes (Scolecophidia), are classed on the basis of some features as lizards by some taxonomists. Bridging between blind snakes and the Alethinophidia (literally ‘true snakes’ ) are two species of Indian dwarf pipesnakes (Anomochilus). Modern reptiles are easily distinguished from amphibians by their skeletons, but Permian fossils such as Seymouria cannot be classified unambiguously as either reptilian or amphibian.

There’s plenty more examples, but I’d like to hear what you think before offering more.

Oolon

Quetzal

Oh, Oh! Oolon: ask him why Struthio camelus(ostrich) has a wishbone but can't fly or how Ambystoma mexicana (axolotl) magically turns into Ambystoma tigrinum (tiger salamander)if environmental conditions are right.

Oolon Colluphid

I think you just did.

I'm curious about the axolotl / salamander though. I thought axolotls were simply neotenic salamanders anyway, just add iodine. [Edited to add: we had one in a big tank at college, a weird albino-looking thing with yellowy gills. I was sooo tempted to pour in a few drops of iodine... ] How come they get called different species?

Oolon

[ March 21, 2002: Message edited by: Oolon Colluphid ]</p>

MrDarwin

Are you saying you have evidence that these hybrids are fertile?

What does it mean when 2 species can interbreed but the offspring are sterile (e.g., mules)?

MrDarwin

I raised this same point in another discussion recently. It's a major problem that creationists can't answer, and I'm unaware that they have even attempted to address it. Numerous molecular genetic studies have indicated that closely related groups (i.e., those that creationists would consider "kinds" and thus accept as coming from a common ancestor) have histories extending much further back than 4,000 years. Ironically, this also means that creationists are proposing that evolution proceeds much faster than evolutionary biologists believe, if this diversification "within kinds" has happened since the alleged flood, i.e., in 4,000 years or less!

Quetzal

Actually, I probably made that assertion a little more strongly than it warranted. Figures you'd call me out on it. Ambystomatidae are of course all salamanders. The reality is that naturally metamorphosizing specimens of A. mexicanum are morphologically identical to A. tigrinum vasci. They can even interbreed. There's a big argument among herpetologists as to whether they are or aren't justified in calling them the same species. And of course the larval form of tigrinum is practically indistinguishable from our axolotl.

There are over 30 species of Ambystoma, about a dozen of which are neotenic. A. mexicanum is normally neotenic, but can be induced to metamorphosize. BTW: You'd have probably killed the poor thing if you'd added the iodine - to induce metamorphosis, you have to actually inject them with thyroxine, apparently. It does happen occasionally in nature with the "wild type", however.

More than you wanted to know, I'm sure.

Oolon Colluphid

Thanks Morpho!

There's no such thing!

(My wife says I already think I know everything... )

hezekiah jones

So "originally created kind" does mean "common ancestor"? Could it be that creationists are really evolutionists in disguise, just evolutionists that draw completely arbitrary boundaries within their own little "theory" of common descent?

Furthermore the creationists are absolutely unwilling (that is, unable) to indicate where these arbitrary boundaries lie. But they must be somewhere, because they claim the bible says so. They just have no idea where those arbitrary boundaries are, or else are simply unwilling to expose themselves to even more ridicule by committing to any declarative statement about them.

And you call this science? And then you have the gall to mock us? Why is it that creationists pick and choose from legitimate scientific concepts that suit them, and utterly repudiate those that don't? Now they are appropriating depictions of evolutionary trees, and drawing chronological lines through them labelled, "Flood." No wonder so few people take them, or you for that matter, seriously.

You know even less about science than I do. How is examining fossils "theorizing" about the past? "Fossil" is not a theoretical term; "fossil" is an observable term. In other words, it has empirical content. "Star" and "galaxy" are not theoretical terms either, and when we observe stars and galaxies we are examining the past. Yet the expressions "star" and "galaxy" also have empirical content, since the physical objects those words pick out are directly observable.

On the other hand, "electron," "chemical bond," and "photon" are theoretical terms, yet when we talk about electrons we are talking about the present. "Gravity" is a theoretical term as well: gravity is not observable. It has no empirical content. But its effects are holding your feet to the floor, right now.

You have been reading this answersingenesis garbage for so long you have bought into its (actually Henry Morris') ridiculous definition of science, a definition that would permit scientists nothing more than to point at objects and name them, because to do anything more would force them to "theorize" about the "past," and to do so would no longer be scientific. AiG is no place to learn about the philosophy of science.

Here is a question for you to consider:

Do we test theories by observation, or do we test observations by theory?

Think about it.

Peez

What a laugh! Batten knows little about biology (or is deliberately misleading readers), and prattles on in his vague diatribe without saying much of substance. Right from the start, he gets it wrong by giving a ~220 year old definition of species. Of course, he ignores the fact that "species" is a term of convenience used by biologists to refer to certain groups of animals, and according to evolutionary theory are expected to be sometimes rather distinct (in the case of more distantly-related species) and sometimes not distinct at all (in the case of closely-related species, which may be no more different than different populations within a species). He also ignores the fact that his definition (which is what biologists now call "the biological species concept," one of several ways to define a species) only applies to sexually reproducing species, and even then is not necessarily precise.

For example, in any population there will be some proportion of matings that are not successful. Say, for the sake of argument, 0.1%. So, using the biological species concept, we should be more precise and say that a species is a group of organisms that can interbreed with each other at least 99.9% of the time. What do we do, then, with two groups of organisms that can interbreed with each other 99.8% of the time? 99% of the time? 95% of the time? 90% of the time? 80% of the time? 60% of the time? 30% of the time? 5% of the time? 1% of the time? 0.1% of the time? How about if they can interbreed 99.9% of the time but the offspring are sterile? What if they can interbreed 99.8% but the offspring are sterile? What if they can interbreed 99.9% of the time but their offspring are sterile 10% of the time? What if they can interbreed 99.9% of the time but their offspring are sterile 50% of the time? What if they can interbreed 99.8% of the time but their offspring are sterile 90% of the time? And then we get to the next generation: the offspring are fertile but might produce sterile offspring in their turn.

Then there are "ring species" and complexes like the leopard frog that Oolon pointed out: A and B can interbreed, B and C can interbreed, but A and C cannot. Which is the species?

Biologists recognize these problems with defining a species, indeed it is biologists who discovered them (and expected them, because this is exactly what would be expected with evolution). "Kinds," on the other hand, should not suffer from this problem. After all, "kinds" are not formed through evolution, right? We should have no problem identifying a "kind," nor should there be any grey areas between "kinds." In fact, I have seen people being accused of being stupid for not knowing what "kinds" are, they are so obvious. Yet, Batten fails to give a clear definition. Why is that?

Peez

Baloo

I think what really kills randman's arguments are his lack of quotes. Oh, sure, he can spout off biology facts, shortcomings in evidence for evolution, and links to articles from aig. And, yes, this makes a very strong case for his creationist views. But, unless he can quote real scientists, like Gould, saying something 15 to 25 years ago which, read out of context, indicate that the scientists themselves disagree with evolution, I'm just not buying his whole point. And one quote simply would not suffice, either. He'd need at least four, if not FIVE quotes to convince me once and for all.

So, randman, how about it? You've got your arguments, your evidence, and your articles... but can you come through in a clutch? Can you produce 5 quotes?