What is the "Missing Link" in science versus evolution?

Great Debates
21

I am not trying to be insulting. I am simply saying that each individual is a link. There is no one individual that suddenly turned from an ape to a human in his or her lifetime. Assuming you have children, Harri, then you are the link between your parents and your kids. Your parents are the links between you and your grandparents. Your parents and your grandparents are the links between you and your great grandparents. All of you are very similar in anotomy and are all members of the same species. But each of you are different in small ways. And if we had skeletons of all your ancestors going back far enough we would note how all the traits that make Harri just as he is today slowly developed.

As another poster said, in order NEVER to have a missing link, you would need fossils of individuals from each generation. With about 5 or 6 generations per century, you would need 50,000 skeletons to show one million years of evolution.
Obviously, that will never happen.

22

[QUOTE=Harri]
Thanks, the Wikipedia articles are interesting but I still notice this in there, too.

“Gaps remain in the fossil record, however; and while some argue that this is a problem for evolutionary theory, most scientists accept that the rarity of fossils means that many extinct animals will always remain unknown.”

So, it still seems that scientists use their “faith in evolution” to fill in the gaps for things they can’t prove. Right?
[/QUOTE]

Gaps in the fossil record are not problems for evolutionary theory. As has been mentioned, that evolution occurs can be shown without reference to a single fossil. What the fossils do show us is thet particular pathways along which life evolved. The fossil record is a test for these pathways moreso than it is a test that it functions at all. The hypothesis is that humans evolved (but not necessarily directly; we share greater affinity with some apes than others) from a basal, ape-like ancestor, and that that same ancestor gave rise to all the other so-called great apes (it is considered a given that we did, indeed, evolve, and that we necessarily evolved from something). Finding fossils which represent intermediate forms between that basal ape and ourselves further strengthens that hypothesis.

So, anyone who argues that gaps in the fossil record represent a problem for evolutionary theory are, to put it simply, full of it. Gaps in the fossil record obscure the pathways through which a species might have evolved, but not that it evolved.

23

[QUOTE=Harri]
“Gaps remain in the fossil record, however; and while some argue that this is a problem for evolutionary theory, most scientists accept that the rarity of fossils means that many extinct animals will always remain unknown.”

So, it still seems that scientists use their “faith in evolution” to fill in the gaps for things they can’t prove. Right?
[/QUOTE]

Nope. What I find that’s common with in cases like yours is that you don’t understand exactly what needs to be demonstrated and how.

First of all, no credible scientist has EVER put forth the idea that every single animal that every lived that is in direct ancestry to a living species or a known extinct species will be found in the fossil record. Anyone that knows anything about the fossil record: how and why there is one, what the restrictions on fossil formation are, and so forth, understands that the fossil record is basically only ever going to give a scattered distribution of a small fraction of all the species that ever lived, and not even a random one (because, for instance, fossilization is very very unlikely to happen in, say an acidic forest environment, and very likely to happen in silt depositing river mouths).

So the idea that scientists are expecting the fossil record to be that robust, and that evolution rests on this being the case, is simply false. In fact, in Darwin’s time, he and others barely expected ANYTHING like the fossil record we have today: they thought it was far more rare and unlikely than it turned out to be. In fact, if you read early works on evolution, Darwin mostly just uses fossils to establish that past life was both very different from modern life, and that most past forms were extinct. He never even imagines being able to map out a complete tree of life from fossils. He demonstrates the reality of evolution in other ways instead: a detailed hierarchical fossil record is then a great confirmation of his theory, not the proof for it.

So the question is: how do fossils work for demonstrating evolution? The answer is that they must: a) flesh out one and only one consistent picture on the so-called tree of life, b) be consistent in every way with what evolutionary theory predicts. And these, the fossil record does do, in great detail. Perhaps even more importantly, the fossil record does something amazing: it matches, again in very high detail, the picture we can independently derive from genetics of what the tree of life looks like.

As Finch pointed out, the fact that there are gaps in the fossil record is just something we EXPECT to see from the fossil record. That’s its nature: that’s fossilization for you. Whether or we have a fossil for a particular species is not a make or break for evolution, though it’s sometimes a make or break for one particular theory or another about exactly what PATH this or that lineage took. And since fossils are only one kind of evidence for these questions, they aren’t even always very important for that either. Fossils tell us a great deal about past life that we cannot tell from genes alone, but fossils and genes together spell out evolutionary history pretty darn clearly.

Think of it as a set of receipts we acquire detailing gas and food purchases made by the same person. From these receipts, we can piece together roughly that this person drove across the country, judging from the speed at which we see a purchase in one town to the next, what and how much gas was bought, and so forth. The person may well have taken a lot of detours and side routes and divergences, and we can’t always tell exactly where he went (though often we can tell how far and how long it took), but we CAN amass enough evidence to demonstrate that they did, in fact, drive from one side of the country to the other.

This is basically what we have with the fossil record. We don’t have detailed evidence detailing every single mile traveled, but we have enough samples to build an overall picture that we have a high degree of confidence in. And, in fact, in the case of evolution, we actually have a heck of a lot more than that, because we can check all this against all sorts of other evidence that we have as well, and even the receipt story vastly oversimplifies the amount of data and insight we can draw from even one fossil.

24

Just to add to those two excellent posts, above:

The whole idea of a “missing link” is something journalists talk about, not scientists. AFAICT, it dates back to the early days of fossil hunting when people thought you had humans on the one hand, and “apes” on the other, and that somewhere out there would be some fossil that would link them together. Every new fossil find was dubbed “The Missing Link” by the press, aided no doubt by the scientists themselves who were only too eager to claim they had find the definitive fossil of a human ancestor.

At the time, we didn’t even have much of an idea which ape we were most closely realted to. Darwin, once again proving his genius, reasoned it was the African apes, but the guy who found “Java Man”, Eugène Dubois, went looking where he did because he thought Orangs were our closest relative. We had no idea at the time how many species we’d find once we started looking into our past. The Peabody Museum web site has an excellent chart of the various species we currently think existed since the time that the human and chimp/bonobo lines split about 6M years ago. No one thinks that’s an exhaustive list, and note that the folks who developed that chart puropsely didn’t draw lines of descent-- we really don’t know which species gave rise to later ones (although we can make educated inferences), or whether there are others we haven’t found yet that are in the line of descent to us.

25

As suggested above, every single individual along an evolutionary line is a “link.” So until we catalog the fossil remains of every single individual and his mother and grandfather and daughter and grandson, creationists will continue to point at “gaps” in the record.

26

Just to clear up a few things, I am not a “creationist” who was arguing their point of view. I was simply asking a question about the term “missing link” that I had often heard applied to evolution in newspapers or on TV and I’d never seen fully explained. I’m sorry if asking an honest question pisses people off. The “gaps” quote came from a link to a Wikipedia article that someone here suggested as a source
of, basically, proof of the theory. Since the article mentions that some, and seemingly not just creationists, see some possibly faults in that theory I don’t think I’m wrong for bringing it up. I am hedging my bets about who’s right or wrong in this discussion. I was just looking for more information. Creationists know they’re right
and those who believe in evolution are only 99.9 per cent sure. And both sides get pissed off at being questioned. Why? The creationists will be just as much dead meat in the ground as everyone else if it’s evolution and the evolutionists (including the ones here) will be begging forgiveness if they’re wrong. Right? But simply asking questions shouldn’t be judged as foolish or wrong.

27

Sorry, buddy, but “So, it still seems that scientists use their “faith in evolution” to fill in the gaps for things they can’t prove. Right?” is a classic creationist line, almost word for word.

If you say you aren’t one, I’ll believe you, but if you walk onto a fancy restaurant dressed as a waiter, you can’t complain or blame the people for asking you what the specials are.

Wikipedia is a great resource, but not a perfect one. The consensus amongst scientists is that evolution is sound. The “some” referred to in the article, if we are to take it seriously, pretty much does, to a man, refer to creationists.

Again, you seem to be assuming that the matter of evolution is a matter of theism vs. atheism. Just so you know, this is, yet again, another classic creationist gambit. Evolution is a scientific theory, not a theology. There are many top evolutionary biologists who are also theists and Christians.

28

[QUOTE=Harri]
The “gaps” quote came from a link to a Wikipedia article that someone here suggested as a source of, basically, proof of the theory.
[/quote]

Nobody suggested it as proof of anything. There are no proofs in science. Colibri referred you to it as a good starting point for a layman examining the nature of transitional forms.

The article mentions only two faults not put forth by creationists: that the concept is a human construct and that the ‘tree of life” is more like a multi-stemmed shrub.

At no point does the article mention the fault that you proposed, ie that scientists take the theory on faith.

  1. People only “believe” in evolution the same way they “believe” in gravity, the germ theory of disease and a round Erath. It’s disingenuous of you to suggest that such beliefs are comparable with belief in a seven-armed, blue-skinned creator deity or a magical sky pixie.

Not at all. Scientists take great delight in being questioned honestly, as do a tiny minority of creationists. Of course nobody enjoys being subjected to dishonest questioning.

  1. There is no such thing as an “evolutionist”. No more than there is such a thing as a “gravitationist” or a “germist”. These things are all matters of fact, not issues of faith.

  2. You are engaging a false dilemma.. The position is totally illogical and certainly has no place in a rational discussion. With literally thousands of different deities out there the vast majority of creationists will be begging mercy even if creationism is right. Vishnu or Tiamat are hardly likely to be pleased that someone attributes their creative work to Jehovah or vice versa, now are they?

Well yeah, it should if those questions are offensive, begging, leading, disingenuous or otherwise illogical or intellectually dishonest.

Certainly rational questions asked in good faith should not be judged foolish or wrong. But surely you aren’t suggesting that questions like “Why are niggers so dumb?” or “Do you still beat your wife?” should be considered wise and correct just because they are questions.

29

There are no proofs in science?! Wow, that sorta
leaves you off the hook doesn’t it? And the “belief” in evolution is the same as the “belief” in gravity? Gravity can’t be proved?!

Otherwise, thanks to the person who gave me that link to Wikipedia. It was meant as a nice gesture
and that’s how I took it. I didn’t mean “faith” to mean anything other than convinced. Faith in anything, whether in science or religion seems
silly. Everything should have to be proven beyond a reasonable doubt. Nothing that’s unproven should be taken on faith. I didn’t know what the
term “missing link” was exactly supposed to mean
and if it did create a reasonable doubt in evolution that’s never been proven. It was
meant as an honest question.

30

[QUOTE=Harri]
There are no proofs in science?! Wow, that sorta
leaves you off the hook doesn’t it? And the “belief” in evolution is the same as the “belief” in gravity? Gravity can’t be proved?!
[/quote]

I’m not sure you are really understanding. There is no absolute proof in science. There is proof in the everyday sense of the word, just as there is fact. It’s just that none of those things can or ever SHOULD be declared 100% certain, because everything is subject to eternal checking and re-checking the evidence. Science is an epistemology, not a theology.

Agreed. That’s what’s so good about science: it doesn’t work on faith.

That’s the basic ethic of science: don’t tell me, show me. Prove it.

Indeed.

Ok, well, did we answer the question? The term missing link is a bit misleading in the sense that it implies that what’s missing is a crucial proof of the fact of evolution and common descent, rather than missing details in lineages, of which we will always be missing such details. The fossil record will never contain every single generation of every species that ever lived, or even every single species.

31

[QUOTE=Harri]
There are no proofs in science?!
[/quote]

As has already been said, that is correct. Science works on probabilities, not on certainties. Of course, some things, such as the fact that the Earth orbits around the Sun, and that life on Earth has evolved over time, have been demonstrated to such a high level of probabilty that they can be considered to be “proved” in the popular meaning of that term. I would say that the probability of evolution being true is not 99.9%, as you have it, but more like 99.99999999999%. Would you consider that “proved”?

How so? One still has to demonstrate that some hypotheses, such as the evolution of life over time, has a very high probability of being correct, while others, such as the independent creation of life forms, has essentially zero possibility of being true given the available evidence.

There are certain observable facts about the interactions of objects, such as the fact that they appear to be attracted to one another over distance and that this attraction appears to depend on their mass. There have been various attempts to explain the rules of this attraction. Newton’s theory of gravity did pretty well for objects in our conventional frame of reference, but needed modification at other scales. Some of this was accomplished by Einstein’s relativistic view of gravity, but even this is incomplete. We are still fairly far from understanding gravity.

In the sense that you are using the words here, then evolution has been “proven,” and creationism has been “disproven,” far beyond any reasonable doubt. And as has already been pointed out, there is no “faith” involved in science. There are certain demonstrable facts; and there are explanations for those facts that have a certain level of probability. Evolution as an explanation for known facts has an extremely high level of probability.

I hope we have adequately answered that question. “Missing link” is a popular, not a scientific term, and in any case has been long out of date. Many transitional fossils have been found; but even if they had not, this would present no real problem for evolution, since there are many other kinds of evidence available besides the fossil record.

32

Not at all. Just because scientists never say that anying is absolutely poven doesn’t mean that something can be absolutely disproven and there are a number of ways in which evoluton could be disproven at any moment. Find a precambrian hominid or camel bone and you will have succeeded. One of the most compelling aspects of the fossil record is that the geological location for every fossil is a test of evolutionary theory unto itself. Evolution predicts that fossils will always – without exception – be found in a certain order in the geological column. Find one fossil out of place and you falsify the theory. But of the millions of fossils which have been found, not a single one has ever been found where it shouldn’t be. What are the odds that, purely by chance, and after centuries of searching and millions of tests, the fossil record would be distributed in such a way as to maintain a 100% batting record for the distribution predicted by evolutionary theory?

33

Finding an out-of-order fossil record would not invalidate evolution. It might invalidate certain models of the evolutionary timeline, but wouldn’t affect the reality of speciation, for example.

34

[QUOTE=Harri]

and those who believe in evolution are only 99.9 per cent sure. And both sides get pissed off at being questioned. Why? The creationists will be just as much dead meat in the ground as everyone else if it’s evolution and the evolutionists (including the ones here) will be begging forgiveness if they’re wrong. Right? But simply asking questions shouldn’t be judged as foolish or wrong.
[/QUOTE]

Science is all about asking, and getting asked, questions. Getting a PhD involves getting grilled about your work by your committee. Those who ask incisive questions in seminars and in conferences are looked upon highly - and when you give a paper, you are expected to be able to answer well. When you submit a paper, you always get questions from the reviewers, and if you can’t answer them, your paper gets rejected. Papers submitted to archival journals may go through several rounds of back and forth. No blasphemy or heresy in science - but you need to have data available to back up your position.

I’m glad you accept evolution, but if you truly understand how science works, you’ll feel even better about your position.

35

I call BS. You’re clearly advocating a religious view here, especially with the “you’re gonna burn in hell” remark.

36

You know, on another level this is actually a pretty good debate question…and one I really don’t have the answer too. What IS the missing link that prevents some people from seeing and understanding the nearly overwhelming evidence that evolution is a fact? How can they look at the evidence from all the different fields that support evolution and still think its something thats faith based among scientists? I mean, I’m all for folks being religiously oriented and having faith and god and all…I don’t subscribe to it myself, but I’m a ‘to each his own’ kind of guy…but this smacks of willful ignorance at this late date. Ok, maybe when Darwin first proposed this (over a freaking century ago!) it was radical and new and not the evidence hadn’t had a chance to build up…but gods and devils and the deep blue sea guys! That was over a hundred years ago and in the mean time all the evidence continues to support the fact of evolution. And in that time NO new theory has been put forward that would support the overwhelming evidence.

So…whats the missing link here? Being a religious fanatic explains some…but the rest? WTF?

-XT

37

Amusingly, research into evolution is actually more advanced that that into gravity - a biologist can observe natural selection in the lab by subjecting a dish full of bacteria to various environments, with half of so of the sample killed off and the more tolerant/adaptable survivors free to multiply. Subject this to a few hundred trials and the end result could be quite different from the beginning.

As far as I know, similar simulations of gravity have only gone as far as putting people and objects into giant centrifuges. Comparatively speaking, it’s a much simpler and cruder process that doesn’t perfectly match the natural phenomenon.

38

[QUOTE=Bryan Ekers]
As far as I know, similar simulations of gravity have only gone as far as putting people and objects into giant centrifuges. Comparatively speaking, it’s a much simpler and cruder process that doesn’t perfectly match the natural phenomenon.
[/QUOTE]

No, there are lots of experiments you can do concerning gravity. The moon landing, for instance, can be considered one big experiment. Scientists have also measured the graviational attraction of objects in the lab.

39

[QUOTE=John Mace]
No, there are lots of experiments you can do concerning gravity. The moon landing, for instance, can be considered one big experiment. Scientists have also measured the graviational attraction of objects in the lab.
[/QUOTE]

However, the basic process responsible for evolution, natural selection, is far batter understood than the basic nature of gravity; the postulated fundamental particle of gravity, the graviton, is not even known to exist at all. I would agree that evolution is much better understood at a fundamental level than gravity is.

40

[QUOTE=Don’t Call Me Shirley]
I call BS. You’re clearly advocating a religious view here, especially with the “you’re gonna burn in hell” remark.
[/QUOTE]

Thanks to everyone for the answers. Missing link was a common term that I often heard growing up but now seldom do and it was often presented as
the crucial link. So I think it is good question and one that the average person couldn’t explain or answer. I don’t advocate any religious views
and often do just the opposite because I just
can’t buy it. That’s not BS. I didn’t say anyone was “gonna burn in hell,” I said they would be begging forgiveness if creationists turned out to be right. And that’s just honest. One of my favorite quotes was from a well-known atheist (can’t remember who it was) who was asked what he would say if upon his death he found himself at the gates of Heaven. I expected a smart-ass answer, but instead he said he would simply say, “Gentlemen, I was wrong. I apologize.” That’s a great and honest answer. People deny the facts of evolution (if they are all truly there) because they bring no comfort to them. And although the odds are MUCH against it, they might be right. It can’t be dismissed. Woody Allen once did a TV special with Billy Graham (“He knew God personally. They used to go out on double dates together.”) And Graham later said something along the lines of “Most religious people would be better off if they thought about religion as seriously as Woody Allen does.” I side with Allen on this (no matter what damage has been done to his rep lately). But it’s worth thinking about, because I don’t buy that scientists can accept evolution as a fact and also buy into religion.
I think they try to word it just to soften the blow of their cold hard facts to the average person. I was just looking for info and possible flaws in those cold hard facts to see if they are all there. As when WC Fields was near his death in the hospital and a friend was shocked to find him reading the bible and asked “Bill, what are you doing?” and he said “looking for loop holes.”
Underneath the joke is an honest hope. It is a big issue.