Dr Rick

scigirl said:
Douglas replied:
and then later explained...

Just so we're clear, then: a struggle for limited resources does not implicitly assume that God does not exist. In other words, one can believe in god(s) and still accept scigirl's original assertion.

The debate is over evolution, not the existence of a god. Acceptance of evolution does not exclude god-belief.

Rick

[ December 09, 2001: Message edited by: rbochnermd ]</p>

NeilUnreal

Since you are substituting the debate for working on your thesis, I'll play thesis committee. The logician in me is compelled to point out that the first sentence, as phrased, is an example of begging the question. The second sentence is a confirming instance, not a proof. (i.e. The fact that species are difficult to define is consistent with the TOE, an example of inference, not deduction. Used deductively, it is affirming the consequent.).

Just kidding! I remember how easy it was to find excuses…

-Neil

p.s. I think both parties are doing a pretty good job of keeping the debate civil and on-topic. I worry that a lot of axioms and assumptions remain undefined which will cause the debate to drift and lose focus.

[ December 09, 2001: Message edited by: NeilUnreal ]</p>

Douglas J. Bender

RufusAtticus,


You said:
All those show is how similar in "design" certain species are - they do not show "relatedness" through "descent" necessarily. (Just thought I'd point that out.)

Sure there is - my definition. Is it conclusively known that apes and humans could, genetically speaking, produce "offspring" (embryos, even)? And, there is the little issue of, according to others' broader definition of "species", "reproductive isolation", which is particularly true of apes and humans (they are "reproductively isolated", according to a number of "measures").


I had said:
"Relatedness" as in "similarity", not as in "genealogy". A Ford Bronco is "closely related" to a Chevy Blazer, but they are not "related" by "descent" (two different manufacturers).

Now, the Bible says that God's creatures and plants reproduced "after their own kind" - it doesn't say what would happen if two creatures of "closely related" kinds were to mate. That is, if a lion and a tiger are two "kinds", the Bible "merely" says that all lions, in mating with other lions, will produce only lions; and all tigers, in mating with other tigers, will produce only tigers - it doesn't say what will happen if a lion and a tiger mate. So, a question to those who deny the existence of a Biblical "kind" might be, for example: Has it ever been observed that two lions gave birth to something which would not be considered to be a lion?

I would say, however, that the apparent similarities between a lion and a tiger are greater than the apparent similarities between, say, a Great Dane and a border collie; and the apparent dissimilarities between a lion and a tiger are less than the apparent dissimilarities between a Great Dane and a border collie (from all I know). The Great Dane and the border collie are of the same "kind", however.

In Christ,

Douglas

NeilUnreal

As rbochnermd points out, this is a non-sequitur. However, I can see cases where the larger point Douglas is making could legitimately affect the debate. If Douglas has reasons to believe some view of nature is axiomatic, it will affect the probability he assigns to various explanations of the evidence. You've got to either: 1) accept Douglas's axioms (for the purposes of debate), 2) get Douglas to accept other axioms (for the purposes of debate), or 3) debate the choice of axioms.

I realize I'm being nit-picky here, but I think it's things like this that distinguish a formal debate from an informal discussion.

-Neil

Douglas J. Bender

theyeti,


You said:

That's roughly my idea, at least at this point. Now, I think the "cat 'family'" is a fairly clearly distinct group (distinct from, say, the "dog family" and the "primate family"). Can lion sperm fertilize a housecat egg? Or vice versa? If not, then it is definite that they are not of the same "kind", according to my definition. If they can, then this would suggest that the "cat-kind" would be broader than appearances would suggest - however, it is my opinion that, in either case, the Bible should be understood as implying or suggesting that, for the purposes of bringing animals onto the ark, "small cats" (house cats, etcetera) are of a different "kind" than, say, lions and tigers. I don't think the same could be said for all types of dogs (for example, I believe that there were a male and a female of only one "type" of dog was taken onto the ark, and a male and female of only one "type" of "small cat" was taken onto the ark).


No, that's only true for one particular "biological definition" of "species" (although it might be the currently most popular definition). But, with that "definition", one could claim that, prior to ocean travel, American Indians and Africans were two "different species" of humans, which is clearly untrue.

With such a broad definition, one could also argue that the industrial revolution has produced several "species" of humans - those who work "day shift", and those who work "night shift", and also those who live in the country, and those who live in the cities. Each of these is, in a strong sense, "reproductively isolated", it seems.


Then, as I sugggested, the American Indians and Africans were (and are?) two different "species" (or "kinds") of humans. Is that what the implication would be?


Absolutely it does. Can a lion and a bear, or a tiger and a kangaroo, or a lion and a hyena, be "bred with each other in a zoo"? If not, then a lion and a tiger being bred with each other in a zoo says quite a bit, actually.


No, not really. That's assuming "behavior" is equated with "genetics", and it's not.


Well, yuppies don't often "interbreed" with rednecks, but I wouldn't use that as evidence that yuppies and rednecks are two different "species". I'm not being sarcastic, but trying to be slightly humorous in making a point.

Here is what Douglas said about cats and "kinds" on this thread:


You said:
I don't agree that, even if lions and tigers are two different "kinds", that the number of "kinds" would pose a problem for the size of the Ark. I have heard from some that the number of different "species" (which they equated with "kinds") would have been around 2 to 4 million (or thereabouts). When I researched this claim a little further, I found that more than half of those were different types of bacteria, which obviously would not affect space requirements. I found that the great majority of the remaining "species"/"kinds" were of the size of small insects, like ants of various types. Again, not a great demand on space resources. The remaining "kinds" were of the "rodent" variety, again a type which would make rather "meager" space demands. All-in-all, there does not appear to be all that many different "large" animals which would have needed to be taken on the Ark, relatively speaking. And if very young males and females of the "large" animals were taken on the Ark, this would further greatly reduce the space requirements.

Regarding the "juvenile versus adult" issue of the animals on the Ark - the Bible says that the "male and his female" of each "kind" was taken on the Ark. This does not mean that the two had reached sexual maturity, but only that, in the course of time, they would be "male and female" - a "couple". It would be like, in a particular culture where the parents choose the spouses for their children when the children are young, the future wife of a young boy might be called "the fiance/spouse of so-and-so". Future-looking, so to speak.


You said:
Which ones would those be?

In Christ,

Douglas

MrKrinkles

I have read that Chihuahuas and Irish Wolfhounds can not mate directly, but are considered part of the same *ring* species because they mate with intermediate-sized dogs and thus there is gene flow between the two breeds. I don't know if the
barrier to mating is only because of the difference in size or if it is also because their sperm and eggs cannot join to produce viable offspring. Anyone else know about this?

Brooks

[ December 09, 2001: Message edited by: MrKrinkles ]</p>

scigirl

Oops, sorry about that! So can dingoes breed with US dogs?

scigirl

scigirl

You should be a Lawyer, not a scientist!

If you see a picture (or moving icon) that you want to post, do this (I hope you don't have a mac because these instructions won't work )

Right-click on the picture and click on "properties." Note the address (url) that comes up. Highlight the entire address and copy it. Then return to the "post a reply" screen, click on the Image button under "instant UBB code," paste your picture, and you're done! The URL works in a similar manner, except you have to not only enter the web address, but also a name for it (like "Here's an abstract").

Mwa ha ha! You are funny, Douglas!

scigirl

theyeti

Douglas:
No, when we speak of the "biological" species definition, we are talking about a formal definition -- one that is different than, say, the "morphological" species definition. I know it can get confusing, because the word "biological" is typically used in a very broad way. But in this case there is one single formal, functional definition.

Your statement about Native American and African populations misses one very important distinction. It is not enough, under the biological species definition, to be geographically isolated, as Africans and Americans once were. This is what I was getting at when I said this:

It's if they do it in the wild that matters. And even if they weren't geographically isolated, I don't think that they would interbreed seeing as how their behaviors are so different (lions are social animals, tigers are loners), but I don't know for sure.

I think it's my fault for not making it more clear. In order to be considered a separate species, it is necessary that African and American populations either could not or would not interbreed, even if they weren't geographically isolated. This is clearly not the case, because after Africans first arrived in America, interbreeding was very common. In fact, much of the population of modern Brazil is descended from both African and American hybrids. Thus, according to the biological species definition, they are the same species.

Now in theory, had they remained geographically isolated for enough time, that they might have evloved into separate species. It would be very difficult, due to the large populations and the potential for gene flow, but it could happen, and presumably would happen, given enough time. But things didn't turn out that way.

The obvious differences that we see between the two groups have evolved because of their geographic isolation since they divergered from a common ancestor. Speciation (again, the bilogical definiton) would simply be the accumulation of more differences to a point at which they would no longer interbreed.

I don't see you argument. None of these groups is reproductively isolated from the others. In some cases, a country dweller may never meet up with a city dweller, but the gene pools of the two groups are not isolated. (Well, in some cases they are. If you ever travel up into the Appalachian mountains, you'll see people who sure look like a separate species.) As long as there is gene flow between, say, the city and the country, then speciation can not occur. And there is, of course, ample gene flow. Theoretically, any of these groups could start down the road to speciation, but the necessary factor is that their gene pools are isolated. Sorry to bold that, but it's an important point to drive home.

Keep in mind also that it's not necessary for two groups to interbreed directly. As long as they both interbreed with an intermediate, then their gene pools are connected. For example, if city dellers and country dwellers never mated with each other, then they would still be considered the same species if each one mated with suburbanites. This is exactly what we're getting at with the domestic dog example. St. Banards and Chihuauas can't interbreed. But each one can breed with intermediate sized dogs and so therefore their gene pools are not completely isolated. If those intermediate sized dogs were wiped out, then the St. Banard / Chihuahua gene pools would be isolated, and thus they would be considered a separate species.

I think I've dealt with this adequately above.

All it means is that tigers and a lions are closely related to each other, which we already knew from morphology. Now for your definition of "kinds", it might make a big deal. But for the biological species definition (which you are free to differ from) what matters is whether or not they interbreed in the wild (again, irrespective of geographic isolation). If they don't, then their gene pools are isolated, and they are thus separate species. According to evolutionary theory (and indeed, the whole of population genetics), once the gene pools are isolated, then they will become more and more different from each other as time goes on. Eventually, they wouldn't be able to interbreed at all, even in a zoo. This is why tigers can't interbreed with hyenas -- their common ancestor is too far back and they've accumulated too many genetic differences.

No, that's assuming that behavior has a genetic root, which it most certainly does. This is especially true of other animals whose brains are not as influenced by the environment as ours are.

Yes, but as long as each one can interbreed with a hippie, then the gene pools aren't isolated.
Besides, there's probably not much genetic difference between yuppies and rednecks; the differences are mostly cultural.

As for the rest of your post, please go back and read my reply to you on the <a href="http://ii-f.ws/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=001471&p=2" target="_blank">Evolution is Proved!</a> thread, to which you never responded (it's okay that you didn't, you just need to realize that your questions have been answered).

John Woodmorappe has to cut all sorts of corners in order to cram critters onto the Ark, and he still fails. The way in which you are using "kinds" would multiply the mass of the animals by probably at least two or three fold. In particular, see a review of <a href="http://www.talkorigins.org/faqs/woodmorappe-review.html" target="_blank">Noah's Ark: A Feasibility Study</a> and <a href="http://www.talkorigins.org/faqs/faq-noahs-ark.html#gathering" target="_blank">Problems with a Global Flood</a>.

As for the dog/bear fossils, I have them listed for you on that same post. In particular is Cynodictis, which is an undifferentiated "dog-bear"; it's a perfect intermediate, and a likely common ancestor.

theyeti

wonderbread

What is your source may I ask? It is rather different from what I have. The following is a chart I found in one of my text books called Biodiversity: An Introduction by Kevin Gaston and John Spicer.

_____________________Number of Estimated species
Type_____Described spp__High__Low__Working figure
Viruses____4____________1000__50____400
Bacteria___4____________3000__50____1000
Fungi______72___________2700__200___1500
Protozoa___40___________200___60____200
Algae______40___________1000__150___400
Plants_____270__________500___300___320
Nematodes__25___________1000__100___400
Arthropods:
Crustacea__40___________200___75____150
Arachnids__75___________1000__300___750
Insects____950________100000__2000__8000
Molluscs___70___________200___100___200
Chordates__45___________55____50____50
Others_____115__________800___200___250

Total:_____1750______111655___3635__13620

[note: All numbers are measured in the thousands, so where it says total 1750, the actual number is 1,750,000.]

So you see, the actual number of estimated species ranges from 3,635,000 to 111,655,000 with most scientists agreeing that the actual number lies somewhere around 13.6 million. Now keep in mind that these are only species that are alive today. There are thosands of organisms in the fossil record of species that are no longer with us. According to the bible and many leading YECs, they had to be on the ark as well. I highly suggest you watch "Walking with Beasts" on the discovery channel tonight to get an idea of some of the humongous animals that exisited in the past, but no longer do today.