gabe

Below is a case for creationism. Does it hold water?


Expectations for evolutionary development of life:
1. Gradual accumulation of life forms
2. Intermediary species (continuity in the fossil record)
3. Transitions within a species (meaning a fair amount of variation
within the species)
4. Selectable phenotypes for species
5. A plausible mechanism for origins
6. Relatedness amonst organisms (like DNA sequence similarities;
genome structure similarities)
7. Generally a gradual expansion of life forms through time.

contrasted with

Expectations of development of life by a non-evolutionary creation mechanism)
1. Sudden appearance of life forms
2. Few if any intermediary species (discontinuity in the fossil record)
3. Little variation within a species
4. Selection of phenotypes not as important
5. A plausible mechanism for origins
6. Maybe relatedness between organisms or maybe little relationship
(expanded upon below)
7. Loss of species over time due to extinction, but no new creation events.

There may be some others that you can think of, but these are some
off the top of my head.

Number 1 does not follow the expectation of standard evolution and
could be consistant with creation. The orignin of life on earth
appeared in much shorter geological time than expected. No adequate
natural explanation is yet available.
Number 2 has some argument from both views, but the majority of
evidence does not show abundant intermediary species. If all life
came from evolution, one would expect lots and lots of intermediary
species. The existance of a few cases that might represent
intermediaries argues that it might be possible to generate species
through evolutionary processes. The rarity of the intermediaries
argues that a different process generates the majority of species.
Number 3 If evolutionary processes are the main driving force of
speciation, there should be a good amount of plasticity within a
species showing the evolutionary process at work. There is some
plasticity as evidence by things like dog breeding. Most
paleontologists however do not view this a the sort of plasticity
that they expect to see due to evolutionary processes. They are
largely agreed that species remain remarkably stable over very long
periods of time. Genes like hox genes which control developmental
programs within each species could potentially give rise to dramatic
changes within an organism, and some believe this is how evolution
works to make abrupt species changes. This could be the case, but
all known hox mutations are deleterious, rather than generating new
species.
Number 4 Some microevolutionary selection can be demonstrated,
particularly if you think of things like bacterial resistance to
antibiotics by picking up a plasmid with a drug resistance gene.
Number 5. So far no plausible natural explanation. The creation
explanation suffers from being outside of a mechanism that science
can test.
Number 6 This is often argued as a strong argument for evolution.
There is DNA sequence homology between organisms in the protein
coding genes. Sometimes genes are organized in similar groupings on
chromosomes of distinct species. This is certainly consistant with
an evolutionary explanation. Also some homologies follow expected
divergences between species. The weakness of pressing too far is
that if a similarity is seen, it is argued to be due to evolution.
If a difference is observed, it is argued to be due to evolution.
Thus, no matter what you see, it can be argued to be due to
evolution. A creation argument for the similarities between species
is that they had the same designer. For instance, all cars have many
of the same recognizable components. Although there are many forms,
you can easily see many core similarities. However, you would never
argue that they were related to each other due to some natural
evolutionary process. They are recognizable as related because they
were designed by the same mind (the human mind). Thus, if God
generated life, he would probably use the best form (DNA) over and
over again. If it is the best way why can evolution use it but not
God.
Number 7 There has been a loss of species over time more consistant
with an early creation followed by loss by extinction. The loss
indicates that evolutionary processes of generating new life forms is
slower than mechanisms that lead to extinction.

I think that overall, the data suggests a supernatural origin of life
(and the universe) followed by much slower natural processes like
evolution. I think natural processes do occur and that they can
occasionaly give rise to a new species, but the data suggest that to
be a rare mechanism. Supernatural creation followed by natural
processes actually encompasses both positions. One does not have to
say it is all natural processes (which doesn't fit all the data), or
it is all supernatural creation (which also does not fit all the
data). Instead, to me the data argues that supernatural events were
required for origins and the development of nearly all the species,
and that very slow natural processes are also working on these
species. However, the supernatural part is the rate-limiting step
(to put it into biochemical terms; after all, I'm a molecular
biochemist).

beausoleil

Hi, not going to engage with all your points but this interested me.

"The orignin of life on earth appeared in much shorter geological time than expected."

Who says, expected by whom and according to what theory?

MyKell

Absolutely not

What? where did you get that idea from?

Do you understand how an organism would fossilize? We're lucky enough to get what we have! In fact there is an enormous number of intermediate species. Two weeks ago in nature there was a discover of a 4 winged dinosaur, the most probable ancestor of moder birds.

Untrue, besides hox duplication rather than mutation per se is thought to have impacted evolution greatly.

What does this have to do with anything? how does this help your argument?

Your number 6 has been shown to be false on various occasions. The last being the Multiple Design Inference thread. Check it out. To make a long story short, teleology is a very inappropriate concept to be used in biology.

An argument out of ignorance.... again and again, we have to explain to people what that means. Dude, how does the incompleteness of our theories help explain that there is a GOD that did all this??? You are not providing evidence for your theory

Principia

Really? Are you actually saying that cars by Ford, Toyota, Mercedes-Benz, et al. are all "designed by the same mind?" Well, this is an argument against individualism if I ever heard one. Why, let's forget about grading children in school, then. All those essays and projects are after all "designed by the same mind."
An optimality claim for the existence of God is usually a loser. Demonstrate to us that indeed DNA is the "best form."

You might be interested in the following link, which makes a more evidentiary argument for the existence of multiple designers than you have for the single designer you conveniently labeled God.

Duvenoy

And most interesting it is, too!


http://news.nationalgeographic.com/n...omaeosaur.html

The Creationists shriek endlessly about a lack of transitional and/or intermediate fossils, yet they can’t move for stumbling over them. It’d be funny, if it weren’t so sad. Lead the horse to water, and so forth.

doov

Theli

And what excacly is the nature of the supernatural origin?
It seems to me that you have very strict views and definitions on evolution, but when it comes to supernatural you simply define it as "not evolution". Based on the extreme lack of knowledge regarding this said supernatural origin, I'm suprised you suggest it as a plausable origin.
You are fantasizing again. What god would probably have done is irrelavent and can only be regarded as a farfetched possibility.
If your version of the creationism has no reliable observations to back it up it cannot be considered a valid substitute for evolution.

And as far as I have seen the debate, the only "evidence" being brought up to support creationism is some holes in the evolutionary theory and a huge pile of missenterpretations.
Both might chip or question evolution at best, but it doesn't prove creationism.

theyeti

This is a bit vague. Life forms can accumulate gradually or quickly depending on a variety of situations. But in general, it's correct to say that gross morphological change is gradual. The evolution of new species is also expected to be gradual, in the sense that they don't pop up all at once, but instead continuously evolve throughout geological time, albeit at different rates.

Okay.

First of all, this is pretty subjective. How do you gauge what a "fair amount of variation" is? Secondly, Darwinian theory predicts that variation will constantly arise; it doesn't predict that there is always a lot of variation at any given point in time. If selection is strong enough, a population can be genetically homogenous or nearly so.

Well yes, but that's a trivial observation. Unless you think that no feature of an organism is adaptive.

If you mean the origin of life, then this is not properly a part of evolutionary theory. What evolutionary theory needs (or actually, what it is), is a plausible theory of divergence and change over time. As for the origin of life, there are plausible mechanisms, but none are deemed likely at this point.

Not just similarities, but the pattern of similarities. Similarities per se mean nothing.

This isn't too clear. The number of species can either increase or decrease in evolutionary theory. Obviously, if you start out with species number = 1, you can only increase from there. But there is no reason to expect a constant increase in the number of contemporaneous species. The number of species may plateau, for example, and remain constant for a long time, even though there is turn-over. Or there may be a mass extinction which lowers the number of species, followed by a burst in species evolution. The only thing expected to increase over time is the total number of species that have ever existed.


Okay, but it's clear from Earth history that all or most species did not arise at once. New species have continuously arisen.

There's no reason why this is a prediction of "creation". It's a potential falsifier of evolutionary theory, but it's not a prediction of creationism. An omnipotent creator could create intermediates if it wanted.

As above, this is totally subjective. And it's not a prediction of creationism. Why can't there be a lot of variation within a species according to creationism?

Not as important as what?

I think you meant to say implausible. Again, this is not a prediction of creationism. There is nothing about a god creating organisms that prevents a natural origin as well. If a natural origin is implausible, then at most that falsifies a natural origin; it does not make any given supernatural hypothesis any more likely than any other.

Maybe? Or maybe a little? Not exactly a prediction then, is it?

Given that speciation has been observed, this would be an example of a falsified prediction. (Though a progressive creationist scheme wouldn't predict this.) If you choose to go above the species level and use "kind", then you've got a lack of specificity problem. I've never seen any creationist define "kind" in a non-question begging manner.

The origin of life or how quickly it happened is not relevant to evolutionary theory. There is as of yet no reason to believe that it should happen within a certain time frame or take a long amount of time. Some scientists who study it think that it will happen quickly (i.e., a few million years) under the right circumstances, and others think it is very unlikely to happen at all, but will happen at least once in a very large universe.

As for the appearance of species, this is indeed something that happens gradually, in the sense that new ones appear all throughout geological time. So this would falsify any "all-at-once" creation hypothesis, leaving only a progressive creation hypothesis viable.

Intermediate species and intermediates between more inclusive groups are quite common. The rarity of intermediates is an artifact of the fossil record. Fossil are preserved only rarely, many are destroyed, and we've only found a tiny fraction of 1% of those that are out there. New intermediates are being found all the time. The ones we don't have are a matter of missing data, not a matter of incongruent data.

I'm afraid this is not representative of what paleontologists believe. The Punc Equers think that species remain stable for perhaps thousands of years and then can speciate quite quickly. But this is actually quite rapid on the geological scale. The changes we have seen in dog breeds have occured mostly within two hundred years, which it too short of a time to be visible in the geological record.

Hox genes themselves, except for rare circumstances, are unlikely to be involved in speciation. Given that all mammals, for example, have the same Hox gene organization, it obviously takes a lot less than a change in Hox genes to cause speciation and a great deal of subsequent evolution. It is likely that changes in Hox genes, including duplications, are imporant in major morphological patterning. But these have only happened a handful of times over the last 600 million years, and no one really expects us to observe this happening now. There are reasons to think that bauplanë continue down certain trajectories such that it's unlikely to cross over to another one, but this doesn't mean that there isn't constant morphological change.

Not to mention the de novo evolution of such a gene. There are actually quite a lot of examples of observed "microevolutionary" change (for lack of a better word).

If you're talking about the origin of life, there are plausible mechanisms. It's just that we lack the necessary information to know if they're actually probable. Nor are we anywhere close to knowing the full range of possible mechanisms. This is just one of those things that needs more time to figure out. I am glad though that you acknoweldge that the creation hypothesis is untestable.

As before, it's the pattern of similarites and differences, not mere simliarity and difference per se. For example, all mammals have hair. Fine you say, but that's just because you took all animals with hair and called them mammals. Not so; all mammals also have three middle ear bones, mammary glands, anucleated eurythrocytes, and about 100 other similarities. A creator could simpy mix and match these similarites with different groups, but evolution could not. For example, if we found an animal that had mammary glands and also had feathers, that would be problematic for evolutionary theory. What evolutionary theory predicts -- and what we observe -- is a nested heirarchy for morphological and molecular traits. This is what allows us to build phylogenetic trees, and the good matches between trees constructed with different characters lends strong support to evolutionary theroy. None of this is predicted by creationism. Yes, a creator could make organisms in a nested heirarchy if it wanted to. But it would be limiting the full range and adaptability of potential organisms, which is an extremely odd thing for an omnipotent designer to do. Afterall, human designs are not limited in this fashion.

But there has also been a gain of species over geological time. The total number of species that have ever existed has steadily gone up. I guess that according to a "one-time-only" creation hypothesis, the number of species would remain flat since the creation event, but this is impossible to reconcile with the fossil record.

No it doesn't. As before, there is no reason to expect the total number of contemporaneous species to always increase. Right now there's a lot of extinction thanks to human beings. There will be times when the rate of extinction exceeds the rate of speciation, and times when the opposite is true.

As opposed to a non-molecular biochemist?

theyeti

Gracchus

Some thoughts about the original post in this thread, considering what differing observations might be made vis-à-vis creation and evolution:

1. c. Sudden appearance of life forms

e. Gradual accumulation of life forms

The fossil record indicates that for a very long time there were only a very few forms of life: e.g. stromatolites and bacteria appeared 3.5 billion years ago. The Burgess shale, dated to a mere half-billion years ago, shows the Proterozoic existence of soft bodied species, some extremely hard to place in the modern classification system. Moreover the Burgess shale has a number of organisms that are difficult to fit into modern phyla.
Cambrian fossils show the development of hard-bodied species, which probably occurred because of the replacement of the primitive reducing atmosphere with an oxidizing atmosphere generated as a consequence of photosynthesis.

2. c. Few if any intermediary species (discontinuity in the fossil record)

e. Intermediary species (continuity in the fossil record)

Actually there are a great many species in the fossil record showing characteristics between earlier and later forms e.g. the therapsid to mammal transition and the transition from ornithischian to bird. Moreover, you have overlooked that every organism leaving descendents is a transitional intermediary.

3. c. Transitions within a species (meaning a fair amount of variation within the species)

e. Transitions within a species (meaning a fair amount of variation within the species)

Some species do show a wide range of genotypes. Other species (e.g. the cheetah, and humans) show evidence of having passed through an "evolutionary bottle-neck", a near extinction event, leaving a more restricted variability. Genes that operate by causing drastic variations in early ontogeny are far more likely to produce lethal effects. Natural selection is a conservative process. The same hox gene that causes segmentation in arthropods and annelids produces segmentation in chordates. But in chordates the bauplan is an inversion of the arthropods'. From an insects viewpoint, chordates are belly side up.

4. . Selection of phenotypes not as important.

e. Selectable phenotypes for species.

…and then there was the evolutionary speciation of fruit flies in the laboratory. This was produced by dividing an originating population (closely inbred, with a highly uniform genotype) in two, and subjecting each sample to differing selection pressure (temperature). After a few hundred generations the two populations could not interbreed.

5. A plausible mechanism for origins

c. e. Although several possible hypotheses have been put forward to explain abiogenesis, it may well be that the actual origin of life will never be known. My admittedly erratic intuition suggests that scientists will one day produce life by more than one method.

6. c. Maybe relatedness between organisms or maybe little relationship (expanded upon below)

e. Relatedness amon(g)st organisms (like DNA sequence similarities; genome structure similarities)

I would state this with one slight difference: What is seen is consistent with the evolutionary explanation. Moreover, the non-coding DNA, where mutations in genotype are not reflected by any discernable change in phenotype, also shows similarities that exhibit more differences with the increasing time since the speciation.

Any thing that you can imagine and much that you cannot, can be attributed to special creation. Special creation can not predict, nor can it be falsified. However, at this point I think you fail to understand the implications of your own argument.
There is no human collective human mind. There are individual human minds, that show a fairly wide variation in quality. Then again, technology and science themselves evolve, keeping the successful artifacts and hypotheses and discarding the failures. You can see descent with modification in many "designed" artifacts. You don't just design a jumbo jet from scratch. You start with kites, progress to gliders, (with many variations being selected out!), then add power for extended flight, etc. Science itself is a refining process, with the occasional paradigm shift taking the place of extinction. A thoroughly fascinating discussion of this concept is to be found in Gary Cziko's "Without Miracles: Universal Selection Theory and the Second Darwinian Revolution" (MIT Press 1995 )

7. Generally a gradual expansion of life forms through time.

c. e. Take a closer look at this. 99% of all species are extinct. How does this show design, much less good design? And we do not find all forms early in the fossil record. And if extinction is on the whole faster than evolution, which I do not contest, what implications would this have for your argument?

For these reasons, I believe that the evidence for evolution is clear and compelling. I see no evidence for special creation, and quite a bit of evidence against it.

JLK

What would you think of these estimates for metazoan species?

Observed transitionals lower bound = ___200_ = 0.08%
Catalogued fossil species       & nbsp;       &nb sp;250,000

Catalogued fossil species = _____250,000_ = 0.005%
Est. total species       & nbsp;     5,000,000,000

Gracchus

I repeat, every organism leaving descendents is transitional. In fact, one of the problems faced by taxonomists is where to draw the line between taxa. Classification is an artifact of of simplification for purposes of discussion. Reality is more complex, and not so clearly defined.