Transitional fossils not proof of evolution?

I am currently engaged in a debate with a Creationist who holds that transitional fossils are not proof of evolution after I posted this http://www.talkorigins.org/...mdesc/images/hominids2_big.jpg
. His example goes thusly:"If I pulled a fossil of a chimp from 5000 years ago and a compared it to the
skull of a man I can make the conclusion that one came from the other because of
similarities, but I would have no proof of that only an assumption based on a
preconceived idea."My response was this:"As fossilisation is an extremely rare process, it's not really suprising that smooth
transitions are also rare. But they still exist, like the hominid skulls I showed. You know
as well as I do that 5000 years is too short a scale, and in this case it's being
manipulated because for some reason, the bloke pulling up the chimp fossil cannot see
chimps today and thusly have his hypothesis falsified, and cannot see the humans from
5000 years ago.What's your explanation for the hominid skulls if not evolution? Did the different species
of hominids just happen to leave fossils that, when taken in a chronological order, show
(what appears to be) an evolutionary sequence?"Am I responding to him correctly? Thoughts?

Thread moved here from the Proposed New Topics forum.

One thing I would be careful of- in science we prefer to avoid using the words "proven" or "proof." Theories can never be "proven" in science to the point where they are completely beyond being reassessed according to new evidence. They can, however, be supported by the evidence - and that's the case with the hominid transistionals; they are evidence consistent with and supporting evolutionary theory.This message has been edited by Belfry, 03-02-2006 06:26 PM

The point that your friend forgot is the sequencing of the fossil evidence.We don't have one "similar" fossil from 5,000 years ago. We have a rather disimilar fossil from 5 million years ago**. We have slightly less dissimlar fossils from 3 or so million years ago. We have somewhat similar fossils from 2 million years ago. We have pretty similar fossils from 1 million years ago.We have very, very similar fossils from 180,000 years ago.This is, of course, all piled on top of a much longer sequence of fossils that have an "arrow" in them too.More later if needed.

Alasdair,Oooh, my favourite! No, because that would ignore the fact that any analysis would place the skull in the chimp lineage. In fact, I doubt whether 5000 years would be enough to even place the skull as being an "archaic" chimpanzee.Were we to imagine a scenario in which evolution didn't occur, then the null hypothesis that your opponent postulates would be that fossils would appear "in-sequence" on occasion, but the rule is that generally you can't make lineages out of the older to younger fossils. In fact, the correlation between cladistics (ordering & ranking of organisms into groups based on (in this case) morphological characters) & where they are found in the fossil record (stratigraphy) correlates to a statistically meaningful degree. In other words, the null hypothesis is falsified & the evolutionary hypothesis is supported. Assessing Congruence Between Cladistic and Stratigraphic DataStratigraphic Consistency Index"The SCI metric may also be summarized either as a mean value for each taxonomic group or as a proportion of cladograms that score SCI values of 0.500 or more, an indication that half, or more, of the branches are consistent with stratigraphic evidence. By both measures, fishes and echinoderms score better than tetrapods. Mean SCI values are: echinoderms (0.773), fishes (0.757), and tetrapods (0.701). Proportions of cladograms with SCI values $0.500 are tetrapods (100%), echinoderms (94%), and fishes (93%). For both measures, values for all three groups are indistinguishable according to binomial error bars (Fig. 3).Within the sample of echinoderm cladograms, nonechinoids show somewhat better results than echinoids but not significantly so (Fig. 3). The mean SCI value for echinoids is 0.724, and for nonechinoids 0.849; moreover, 90%of echinoid cladograms have SCI values $ 0.500,compared with 100% for nonechinoids.SCI values for fish groups are variable but not significantly different (Fig. 3). For mean SCI values, the order is as follows: sarcopterygians (0.904), teleosts (0.744), placoderms(0.741), agnathans (0.733), and actinopterygians (0.722). In all cases, all sampled cladograms show SCI values > 0.500. The rankings of tetrapod groups by both aspects of the SCI metric are comparable. Mean SCI values give this sequence: mammals (0.837), “mammallike reptiles” (0.729), lepidosauromorphs (0.714), dinosaurs (0.698), archosauromorphs (0.660), and turtles (0.586). The low value for turtles is significantly lower than the high values for synapsids, mammals, and “mammallike reptiles”. Proportions of cladograms with SCI values $ 0.500 give this sequence: mammals (100%), “mammallike reptiles” (100%), lepidosauromorphs (100%), turtles (100%), dinosaurs (86%), and archosauromorphs (78%)."In conclusion, Benton's study shows that there is a clear correlation between the evolutionary trees & the stratigraphic location that the fossils are found in. In other words, cladistics shows a sequence of fossil morphologies as per evolutionary expectations that mere chance cannot explain. In even easier language, you can make lineages out of older to younger fossils, & this is in overall terms the order of the day.Mark

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There are 10 kinds of people in this world; those that understand binary, & those that don't

Hello, Alasdair, and welcome to EvC.Good question, and in fact it is one of my favorites. I have already written about this, but I don't remember when or where so I will have to repeat it, I'm afraid. And since randman won't be back for another week, maybe we can have a decent discussion on this topic before it gets chewed up beyond recognition!The reason that transitional fossils are evidence for evolution is that they are exactly what we would see if evolution were true. (By the way, Douglas Theobald has written my favorite web page on the whole internet (and where your picture came from); he also discusses why fossils are good evidence.Basically, if evolution were true, then the Linnaean classification system should indicate the proper family tree relationships between species. Therefore, humans and non-human apes should share a common ancestor. In fact, we can make a scientific prediction: at one time there was a common ancestor for humans and living non-human apes. Therefore, if we are lucky, we might find the fossil remains of creatures that show characteristics intermediate between humans and apes. And we have! These fossils don't have to exist, but they do.This is the main idea. Basing our predictions on the theory of evolution, we have an idea of what types of fossil creatures are possible, and which are not possible.Whales are clearly mammals, and most mammals are terrestrial, and clearly related to other terrestrial animals like reptiles. Therefore, the ancestor of whales must have been terrestrial. A scientific prediction: there once existed, long ago, creatures that showed intermediate characteristics between modern whales and ancient land mammals. And the remains of such creatures have been found! Again, the point is that these fossils did not have to exist, but they do.In embryology, it is known that all vertebrate embryos share certain features in common; one such feature are the pharygeal pouches. In fish, these form the gills (and other structure). In jawed vertebrates, part of these form the jaws. A part of the pharyngeal pouches that forms part of the jaws in reptiles and fish form part of the inner ear in mammals. So a scientific prediction was made: part of the mammalian ear evolved from part of the reptile jaws; therefore there existed creatures with bones that are intermediate between being completely jaw bones and being completely ear bones. And what do you know, they have found fossils with these characteristics are known to exist!Now the point is that these creatures did not have to exist, but they did. The creationist looks at the diversity of life, and it is a random puzzle to her. But an evolutionist sees a definite pattern, and so can make predictions based on this.Bats are mammals. They are actually related (distantly) to primates. It is possible that we will find fossils that show characteristics intermediate between modern bats and ancient arboreal mammals (if we are lucky). Prediction: we will not find fossils intermediate between bats and, say, birds. We will not find fossils intermediate between whales and fish. We will not find fossils intermediate between humans and slugs.So that is why transitional fossils are good evidence for evolution: because the fit the required pattern and are not just a bunch of random animals with no obvious relationships.(By the way, as good as the fossil evidence is, my favorite evidence for evolution is nested hierarchical classification of the species.)

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"Intellectually, scientifically, even artistically, fundamentalism -- biblical literalism -- is a road to nowhere, because it insists on fidelity to revealed truths that are not true." -- Katha Pollitt

You have a wing and I have a prayer however I am a realist when all facts are present. Anyone who can more so except and believe in a theory rather than true evidence is a surrealist and has a lack in logical thought. I say this because much of science is theory and conjecture as well as religion. The basis for all locical thought is what is evident as to the subject matter and what from this can be logically derived. All that exists in it's basic form is atomic matter and all atomic matter has never not existed as non atomic matter. This is basic thought and with proper logic one can see that all matter that exists in the existence of all things has always existed in one form or another with change only comming by way of atomic infusion and by way of for all things organic through growth. Logic then dictates that if organic atomic growth can appear and change from one form to another then creation is the only true continuance of all that exists. Logic also then dictates that if then that all non organic atomic matter can only exist and change to some degree from itself to a differant form of existent matter then creational existent matter is the top of the line form of all existent atomic matter. Reply sharpshooter and prove me wrong. This message has been edited by AdminPD, 05-01-2006 07:56 AM

something to be aware of: evolution is not a straight line. it's a tree. even a chimp 5,000 years ago (or TODAY) tells us alot about human evolution.no fossil we find is ever a node on the tree -- we'd have to find the exact ancestor individual, and that's very, very unlikely. rather, we find specimens on various branches, some closer to the branch that we're looking for than others. with enough data, we can draw the important parts of the tree.most of the hominids in that graphic are not actually in the line of human descent, so the transition that presents is really kind of deceptive. but they ARE indicitive of the changes that were going on.the "chimp" branch just forks off lower on the family tree than the neanderthal branch, and a chimp specimen of any age would tell us that. older ones would just be closer to the trunk.

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Well, the evolutionary interpretations of the fossil record is mostly based on speculative interpretations. This is because the fossil record does not realy support evolution. Since the fossil record never shows a clear step by step evolution, why would any body assume that there was evolution in the first place. Similarities among species is not enough to be evidence for evolution. IN fact, this tree is what evolutionists assume to be true. This is what Darwin hoped. However, the fossil record does not reveal that all species emerged from a single ancestor. IN fact, it shows that the vast majority of organisms phyla (whether in sea, on land or in the air) emerged all of a sudden and fully formed without ancestral species to show a clear gradual evolution. This is still based on the speculation that life is a tree. YOu cannot collect several "branches" together and assume that they evolved. Since the line of hominids is deceptive and does not clearly indicate a gradual evolution, any assuptoin of human evolution would be based on just speculations and bias and not on solid scientific evidence.

You cannot draw that conclusion at all. The fossil record is spotty. Fossilization is rare, and some organisms are more easily preserved than others. The Cambrian "explosion" coincides with the appearance of hard body parts (teeth, shells, etc), i.e. structures that are much more amenable to preservation.However, there are some rare pre-Cambrian fossils (and more being found) that show that many of the basic body plans were evolving well before the so-called "explosion." For some pics of examples and links to more info, see here.Many of your posts (both here and off-topic elsewhere) seem to be arguing against the assumption of phyletic gradualism, which has been essentially abandoned for quite a while now. Also, the fossil record is only one line of evidence, and perhaps not even the most important one. The important thing to understand is that all of the lines of evidence converge and are consistent both with each other and with evolutionary theory.

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Well, the evolutionary interpretations of the fossil record is mostly based on speculative interpretations.

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Actually, the interpretations are reasonable inferences from the data.-

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IN fact, this tree is what evolutionists assume to be true.

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Actually, this tree is real. It was originally discovered by Linnaeus before Darwin. The tree is not ambiguous, not depending on which characteristics are chosen for the classification. More modern methods replicate the tree, and the tree is statistically robust.Of course, evolution is not the only explanation for such a tree to exist; however, in light of other evidence it is a good explanation, and other data tend to confirm evolution.Here is some more information on the tree, just because the hierarchical classification is my favorite piece of evidence for evolution (even though it is, at best, only indirectly relevant to this thread).-

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Since the line of hominids is deceptive and does not clearly indicate a gradual evolution, any assuptoin of human evolution would be based on just speculations and bias and not on solid scientific evidence.

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Actually, the fossil record of the evolutionary history of humans is one of the best, probably because it is so recent.

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"We must respect the other fellow's religion, but only in the same sense and to the extent that we respect his theory that his wife is beautiful and his children smart."
-- H. L. Mencken (quoted on Panda's Thumb)

So you're saying that the fossil record is not complete and fossils are rare. This is the same old and desperate argument that Darwin used before. Now the fossil record is almost complete and provides a huge wealth of information about living species emerging all of a sudden with no evolutionary past. Many evolutionists admit this fact.It is not impossible for soft tissues to survive up to today. The Burgess Shale fossil bed in Canada contains thousands of organisms with fossilized soft tissues because they were mostly covered with mud and had no contact with oxygen. Again, this fossil bed shows no evolutionary past. The Camberian explosion has established more than 60 different phyla. This means tens of thousands of species that exploded into life fully formed. Just finding few fossils that are so-called precamberian does not invalidate the Camberian explosion. We dont know the validity of these fossils or if they realy belong to pre camberian eras. But there are no clear lines in the fossil record because it shows that many phyla emerged suddenly. A famous British paleontologist Derek V. Agar approves this fact: “The point emerges that if we examine the fossil record in detail, whether at the level of orders or of species, we find-over and over again-not gradual evolution, but the sudden explosion of one group at the expense of another”.AS Darwin said, if his evolution theory is true, there should be numberless transitional forms and that they should still exist today. However, the fossil record invalidates evolution. This is because all species that exist today and in the fossil record, are clearly independent of each other and are classified seperately. The so called transitional forms are very limited and most (if not all) of them are mistakelnly thought to be transitional but they are not.If you say the Camberian explosion is invalid, how can 60 phyla emerge in a very short time period (geologically speaking) and fully formed and independent of each other with no evolutionary ancestral species? If there is a gradual evolution, it should take billions of years of evolution to form 60 phyla that include thousands of species.

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A famous British paleontologist Derek V. Agar approves this fact: “The point emerges that if we examine the fossil record in detail, whether at the level of orders or of species, we find-over and over again-not gradual evolution, but the sudden explosion of one group at the expense of another”.

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Where is this from? Who is Agar? I find no reference to him anywhere but islam sites. In what context is he making that statement? He's a proponet of PE isn't he?

Talk about desperate. Denial is like that.What part of the theory of evolution depends on the fossil record for validity?None.Evolution is the change is species through time. This is an observed fact. Several times over, in all locations on the earth.Thus the theory of evolution is validated by observation.Species do change over time. There is no species that does not change over time. There is no species that does not evolve.The theory of evolution predicted that there would be genetic common ancestors before Mendel was known to Darwin, and well before the genetic basis (of mutation and diversification of genes - alleles - within populations) was discovered.When genetics was discovered (with DNA) the evidence of common ancestry was found in the genes of siblings, within species, between closely related species, and between more and more distantly relatied groups of organisms, all showing a tree of development based on genetics.Genetic relationship do not form arbitrary relationships, but very clear ones, due to a number of genetic markers that can only be passed on from a parent species to an offspring species, markers that cannot be transfered horizontally between species. Markers where the exact arrangement and location argues strongly against any other arrangement of the relationship tree.Genetics did not need to conform to the predictions of evolution, but it did, and the conformity continues to become more complete and more thoroughly documented as time passes.There is nothing in the genetic tree of relations that contradicts the theory of evolution of species through time. This validates the theory, as it passes a milestone prediction without being contradicted by the new evidence.The theory of evolution predicts that there would and will continue to be "missing link" fossils of common ancestors.Whenever "missing link" fossils were and are found, they were and are also found to fit with all the pre-existing information forming a tree of relationships, both in time (sedimentary layers) and in space (geographical locations).These "missing link" fossils do not need to conform to the predictions of evolution, but they do, complete and more thoroughly documented as time passes.There is nothing in the fossil tree of relations that contradicts the theory of evolution of species through time. This validates the theory, as it passes a milestone prediction without being contradicted by the new evidence.There is nothing in either the genetic tree of relations OR the fossil tree of relations that says these two different sources of information need to match, but they do. Consistently, and this match between disparate information sets becomes more complete and more thoroughly documented as time passes.The problem for you, is not whether either record is complete, but why there are NO contradictions to the predictions of evolution.The problem for you is why there is NO evidence for any special creation or design.The problem for you is to look at the real world without denying the evidence around you. Denial does not make it go away, or lose meaning. The only thing it hinders is your understanding of the actual creation - by whatever source.Do you think the world is a lie?Enjoy.

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It's misspelled, I assume this quote is supposed to be from geologist Derek Ager. And yes, from what I can gather he was an early proponent of Punctuated Equilibria, which the quote seems to pertain to. Another case where Mr.Matrix mistakenly thinks PE is a problem for modern evolutionary theory, as opposed to an important part of it. ETA: Ager is the unfortunate victim of a number of other common creationist quotemines, especially on the topic of radiometric dating.Edited by Belfry, : No reason given.