Since we’re on “evolution basics” here. Isn’t the chimp closer to us in DNA(markers?) than the Australopithicine? After spending years hearing why evolution couldn’t be possible, I’m trying to weed out the old tales. IWLN
Sure, there are puzzles. Just as there are in any field of science. That such puzzles exist is why people continue to do research in those fields.
As for the “transitional stages” bit, there are a couple of things you need to consider. One is that immediate ancestors (the standard creationist version of a “transitional form”) are very diffcult to pin down precisely because of the bias in the fossil record. As tomndebb mentioned, fossilization is a rare process indeed, particularly for land-dwelling vertebrates (aquatic organisms, especially invertebrates, tend to live in environments in which fossilization is more likely; thus the plethora of shelly fossils compared to, say, bird fossils). The second is that “transitional form”, as used by paleontologists, generally means just that: the form is transitional, even if that particular species is not ancestral. What this means is that the organization and form of a particular fossil species is representative of the changes from one taxonomic category to another. Pakicetus is a transitional form in the evolution of whales, even if modern whales did not evolve directly from Pakicetus. This is a rather subtle point that is lost on many a creationist (and, indeed, some evolutionists!). Another exmaple is Archaeopteryx. Archie itself was essentially an evolutionary dead-end – modern birds did not evovle with Archaeopteryx as a direct ancestor. However, Archaeopteryx is representative of the change in form between theropod dinosaurs and modern birds. Whatever lineage that did eventually lead to modern birds very likely went through stages very much like what we see in Archaeopteryx. Thus, it is not ancestral, but remains an example of a transitional form.
Not at all. Lack of evidence within the fossil record does nothing to evolutionary theory. What matters is that what is present is very much consistent with evolutionary theory. What would matter is if we found something in the fossil record which directly contradicted our notions of common descent (finding, for example, human fossils in Triassic rocks).
It is not questionable that it happens (unless one wishes to posit that God is constantly and continuously creating, which opens up several cans of theological worms). It is questionable which mechanisms operate under which conditions, and which mechanisms migth operate at all. It is also questionable whether we have the tree of life figured correctly; systematists are constantly revising relationships between species based on new evidence. We have the big branches pretty well figured out, but the smaller twigs can prove troublesome.
That there are questions is indicative that the science remains healthy. Once there are no more questions, dogma replaces science, and the field stagnates. Such is not likely to happen any time soon. New discoveries raise new questions, which spur new research.
As others have mentioned numerous times, however, “creation science” is an oxymoron. There is nothing “scientific” about creationism, as it depends wholly on an unverifiable premise. Evolution can occur with or without a deity. Creation requires one.
I just went to borders and picked up darwins black box, hopefully its good… mabye ill have some scientific quores or something to use other than my opinion. Geeze Darwin’s Finch, you sound like a very intelligent mistake.
I guess it’s purely a semantic thing but I would argue that aall species are “transitional” in the sense that no species is ever static or “finished.” They are all just snapshots of a fluid process. You are correct in that there is no goal or intent for the evolutionary process and that no species is a “step” on the way to some pre-conceived end-species but every species is always in transition.
Maybe it’s more reasonable just to say that there is no difference between a species and a “transitional” species. Any perceived distinction in popular perception is biologically meaningless.
Fair warning: Behe will get knocked out of the park around here.
I read a discussion about the book in on of the links I was given in the last page of replys, from what I got from it was that most of you were trying to change the discussion to who behe is rather than his idea of irreducible complexity.
Read more carefully. IC has been debunked many times on this forum.
DtC:
I guess you could say that all species are transitional or that none are. Either might be considered correct. As long as you don’t say that some are transitional and some are not.
There has been no Australopithicine DNA recovered to date, but if there were it would be expected that Homo spaiens would be closer to Aust than to Chimp.
Think about it. Australopithicines appeared in the humnan line after the human/chimp split. So, humans should be closer genetically to Aust than to chimps. But it might be possible that Aust would be coser gentically to chimps than they are to humans.
I do believe that chimps and humans are closer than chimps and gorillas though. Am I mistaken?
Yes, modern genetics apparently bears that out. Chimps are close enough that some propose that they are really just another species of Homo (or we another species of Pan). The genus dividing line is not well drawn genetically and morphologically, as far as I’m aware, and it has less relevance in modern cladistics (again I am no phylogenist, so I may be wrong). Just for example, the genus that I work on has animals as genetically separated as mice and humans all within Drosophila. Perhaps Darwin’s Finch could enlighten me.
I don’t think most of us need to find out who Behe is, or what he is. We already knew.
Just to let you know that his “irreducible complexity” idea has been shard to little bits.
Yes, by the standard measure of “genetic distance”, the chimp is more closely related to humans than it is to gorillas. Which implies that humans and chimps shared a common evolutionary path for some time after the gorilla line split off.
Gorilla is of the genus Gorilla and chimp is of the genus Pan, so neither of the three species is considered to be in the same genus. If you put chimps in with humans (presumably into Homo since that genus was described first), you’d have to also relable every non-Homo hominid ancestor as well. This is unlikely to happen short of data showing that humans and chimps can successfully hybridize. There is a strong argument to be made that, regardless of the genetics, humans and chimps have evolved such different survival strategies that that alone would justify putting them in different genera. And if there is no hybridization in nature, then even contrived hybridization would not necessitate combining the two species (or genera) into one.
Make that …shredd…
:smack:
IANA biologist but IMHO you don’t have to look at fossils for examples of transitional species. There are living examples where you can see every “step” of the entire gradual process of change from one species to another. What I’m talking about are “ring species”. There’s a good succint explanation of the concept here: Ring Species
A longer discussion can be found here: Ring Species: Unusual Demonstrations of Speciation
You can find a lot more info just by Googling “ring species”. It seems to me that these are real living undeniable concrete demonstrations of how micro-evolution can indeed lead to macro-evolution and speciation.
I think the difference is that “if a puzzle is filled with god did it”, then there is no reason to ask any further questions. Perhaps you are content with that, but I am not. But “if a puzzle is filled with i dont know”, the interesting possibilites are practically endless.
Also, just because you don’t know the answer does not mean that god did it. Would god really appreciate you believing in him just because you didn’t have anything better to do? It is important that you make a fully an informed decision as you can.
When I hear creationist/ID’ers say that “evolution is just a theory” I usually think (but I’m too polite to say) “I don’t know which word you understand less: ‘evolution’, or ‘theory’”. I try to be understanding because I know that if you are getting all your biology lessons from the pulpit, you are bound to be misinformed. The church is not well known for disseminating current information. If I’m not incorrect, it took the church about 453 years to admit that the earth revolves around the sun as opposed to the sun revolving around the earth. At least they quit torturing and killing scientists. This kind of stuff makes me suspicious of the churches motives.
If I may make a polite suggestion, and of course if you are really interested, why don’t you get a biology textbook from the used book store. I think you will find it easier to follow than talk.org because you can review the chapters that lead up to the chapters on evolution, etc. It is very helpful to brush up on the basics and most people I know have forgotten alot of the science they learned way back when.
Besides, biology is fun to read about and there have been some changes made since I was in school. The duck billed platypus is a cool aminal to know about and remember the three kingdoms (aminal, plant and mineral)? Well, there are 5 of them now!
Welcome to the boards.
Actually, humans are a transitional species: our skeleton is not fully adapted for walking about upright, and retains several features (toes, curved spine, etc.) from our quadrupedal past.
btw, Darwin’s Finch, I’m jealous! I want to sound like an intelligent mistake too!
Trinopus
You might want to read a book on evolution first so you can discuss it a bit more intelligently. Your question on transitional species makes me think that you have either not read or not understood the links you were given.
BTW, what is your definition of transitional species? Some creationists give absurd, strawman definitions. In fact, many, many, transitional species have been found.
If you insist on reading Behe, please look for the following information:
Who is the intelligent designer?
When did they do the design?
How did they do the design?
Is the intelligent designer busy working today? Things are still evolving after all.
Uh…wha…? Mistake…? (I do hope you are not making a reference to the idea that evolutionists believe that all of life is an “accident”…such is not the case, I assure you.)
Genera, like any higher Linnaean categories, are fairly subjective groupings of species. In general, one would expect a genus to represent a natural clade (otherwise, why group them together?), but there isn’t any obligation for a clade containing members of one genus to only include members of that genus. If species are moved from one genus to another, however, problems can occur:
One could very well re-examine both Pan and Homo and decide that one is synonymous with the other (Homo would have priority in this case, so chimps would have to be moved into that genus, should such transpire). Since Pan really isn’t the sister clade of Homo, though, I doubt that’s likely to happen. Such would require Homininae (Ardipithecus + Australopithecus + Paranthropus + Homo) to be redefined, since Pan currently falls outside of that group.
While renaming chimpanzees wouldn’t necessarily alter the actual cladogram, it would cause a fair amount of confusion since you would then have some species of Homo within Homininae, and some outside of it. That would in turn make Homininae paraphyletic, and Homo would become polyphyletic – which would cause all sorts of other problems. Unless you just redefine Homo to be the current Pan + Homininae, which seems kind of pointless.
You are incorrect. Your claim of torture and killing of scientists is also a fantasy that never occurred. (Bruno was burned for his theological positions on the Divinity of Jesus, not for any scientific speculation in which he may have engaged.) The church has definitely had periods of opposition to as well as periods of support for science and a case can be argued that there has been more opposition than support, but your specific statements are in error.
Do a search in GD for “galileo” to see several discussions of the topic.
Well then please enlighten me as to why the evolutionary theory says these mutations happen if not randomly or by accident. I would prefer that i dont go blabbing along about the evolutionary theory if I am wrong about it.