The Trivers-Willard hypothesis

| 75 Comments

From EurekAlert:

One of the most debated hypotheses in evolutionary biology received new support today, thanks to a study by a scientist at the University of Nevada, Reno. Elissa Cameron, a mammal ecologist in the Department of Natural Resources and Environmental Science, has helped to disprove critics of a scientific theory developed in 1973.

At that time, ecologist Bob Trivers and mathematician Dan Willard said that large healthy mammals produce more male offspring when living in good conditions, such as areas where there is an ample food supply. Conversely, female mammals living in less desirable conditions would tend to have female offspring. …

She conducted an analysis of 1,000 studies that examined the Trivers-Willard hypothesis and sex ratios in mammals. Her study found that female mammals that were in better body condition during the early stages of conception were more likely have male offspring. Body fat and diet can affect levels of glucose circulating in a mammal’s body, and Cameron suggests that the levels of glucose around the time of conception could be influencing the sex of the animal’s offspring.

“A high-fat diet can result in higher levels of glucose, thereby supporting the hypothesis that glucose may be contributing to the sex of the mammal’s offspring,” Cameron said.

The paper is Elissa Z. Cameron, “Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism” Proceedings of the Royal Society of London, Ser. B. 271, 1723 - 1728 ( DOI: 10.1098/rspb.2004.2773).

Abstract:

Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.

75 Comments

I’m waiting for the IDists to explain how using ID theory, this would have been discovered sooner.

I don’t get it – what does this have to do with evolution? It simply states that different environmental conditions can skew the distribution of m/f in the offspring. Seems kind of obvious to a humble physicist. Was it demonstrated that this bias evolved as opposed to simply being present?

David, I’ll bet a pitcher of beer that ill-nourished females have better reproductive prospects than ill-nourished males while the reverse is true for males (a male of most species can sire many more offspring than a female can birth).  The prediction of evolutionary theory is that strategies which improve reproductive fitness will tend to be selected for, so you would expect to find a bias towards male offspring in well-nourished mothers (who can give them the advantages required for successful competition against other males) and the reverse bias in the offspring of ill-nourished mothers.

I still don’t understand–you write “The prediction of evolutionary theory is that strategies which improve reproductive fitness will tend to be selected for, so you would expect to find a bias towards male offspring in well-nourished mothers” – but what about evolution CAUSED this bias? It is not enough to make common sense arguments. That’s not science. To say some “strategy” is behind it without saying how, dynamically, the “strategy” was carried out is the same as attributing it to an unseen intelligence. Where is the evidence that this bias, at some point did NOT exist, and now it does?

So this piece of data happens to fit what evolutionists predict – a great deal of planetary data fits the epicycle model. So what? Until you can give a real theory, that A caused B then C and now we are seeing D, you’re just making wild ass unfalsifiable guesses that happen to be right on occasion.

Science? I don’t think so.

Sorry, I misspoke; I’m an engineer, not a scientist.  The word “strategy” is too loaded with connotations of conscious purpose and is obviously not correct.  I should have said tendency or mutation.

A tendency or mutation can arise by accident, but if it promotes reproductive success and is heritable it will tend toward ubiquity.

“The prediction of evolutionary theory is that strategies which improve reproductive fitness will tend to be selected for, so you would expect to find a bias towards male offspring in well-nourished mothers” — but what about evolution CAUSED this bias? It is not enough to make common sense arguments. That’s not science. To say some “strategy” is behind it without saying how, dynamically, the “strategy” was carried out is the same as attributing it to an unseen intelligence. Where is the evidence that this bias, at some point did NOT exist, and now it does?

So this piece of data happens to fit what evolutionists predict — a great deal of planetary data fits the epicycle model. So what? Until you can give a real theory, that A caused B then C and now we are seeing D, you’re just making wild ass unfalsifiable guesses that happen to be right on occasion.

Science? I don’t think so.

You’re very wrong, it’s definitely science. Discovering phenomena, without have a detailed expanation, is of great importance in science. Before Newton formulated a theory of gravity, Galileo showed that things fell at a rate irrespective of their mass. This was important, though he didn’t have an explanation for it. Albert Michaelson and Edward Morley had no idea what the hell caused their data. Neither did anyone else. But it was science, and important.

Steve, fair enough, but just like Galileo there is no theory here, just observation. What Galileo did was important, but it is not on par with Newton, who actually explained it with a theory.

The so-called theory here is natural selection, but all you can do is say “see these data fit what we expect.” If the data don’t fit, then you say “Hmm, there must be some environmental pressure we are not aware of.” The theory can never fail. It’s a tautology.

David Heddle Wrote:

I still don’t understand—you write “The prediction of evolutionary theory is that strategies which improve reproductive fitness will tend to be selected for, so you would expect to find a bias towards male offspring in well-nourished mothers” — but what about evolution CAUSED this bias?

What caused the bias is the advantage of having sons over daughters, in polygynial species. Here is the logic behind the T-W hypothesis.

But biologists have also noticed that in some situations other animals–including humans–can give birth to an overabundance of sons or daughters. In the early 1970s, Robert Trivers and Dan Willard, both then at Harvard, wondered if mothers might be able to control the sex ratio of their offspring to boost their own reproductive success. They imagined a species, such as deer, in which relatively few males mated with most females. If a doe gives birth to a healthy male, he is likely to grow up into a healthy buck that has a good chance of producing lots of grandchildren for the doe. In fact, he would be able to produce far more grandchildren than even the most successful daughter. He could impregnate lots of mates, while a daughter could produce only a couple offspring a year, which she would then have to nurse. So if the doe is in good health and can give birth to strong offspring, she would do best to produce sons.

On the other hand, if this doe gives birth to a male in poor condition, he may be unable to compete with other males, and his chances of reproducing fall to zero. Since most females that live to adulthood give birth to at least some offspring, it would make more sense to give birth to a daughter rather than a son in poor condition.

David Heddle Wrote:

It is not enough to make common sense arguments. That’s not science. To say some “strategy” is behind it without saying how, dynamically, the “strategy” was carried out is the same as attributing it to an unseen intelligence. Where is the evidence that this bias, at some point did NOT exist, and now it does?

Theorizing is science. In fact it is probably the foundation of most modern science. It is true that attributing a behavior to an evolutionary strategy doesn’t explain the molecular biology behind that behavior. It does however attempt to explain why it evolved.

I responded because I didn’t know you were a creationist. Not understanding how it’s important could have been a reasonable complaint, claiming that this example shows evolution’s a tautology isn’t. I don’t argue with unreasonable people, but there are several people here who do because they like the practice, so I’ll leave this to them.

David Heddle Wrote:

Steve, fair enough, but just like Galileo there is no theory here, just observation. What Galileo did was important, but it is not on par with Newton, who actually explained it with a theory.

No theory here? No theory here? Did you miss the part that the study was testing if the Trivers-Willard hypothesis fits with mammalian biology? The T-W hypothesis is well grounded in Nobel-prize winning theory. The classic application of it is to fig wasps, a species where the female has a clear choice over the gender of her offspring.

The so-called theory here is natural selection, but all you can do is say “see these data fit what we expect.” If the data don’t fit, then you say “Hmm, there must be some environmental pressure we are not aware of.” The theory can never fail.

Selection never fails? You don’t know much about neutral theory do you?

It’s a tautology.

LOL, 1+1=2 is also a tautology.

I am not a creationist – at least not a young earth creationist.

I did not say selection never fails, I said that the Theory of Natural Selection can never fail, it is sufficiently malleable that it can be adapted to any result.

Unless I missed something, the hypothesis was that there would be a bias in m/f births based on environmental conditions. And so there was. I just don’t see how this can be heralded as a victory for evolution. Fitting the data is fine, but a theory should have predictive power and should be testable.

Another way to put it: no outcome of Cameron’s study would have been recognized as a blow to evolutionary biology. If the study had turned out the other way, would it have shaken any foundations? Caused any text books to be rewritten? Nope. Nothing can shake evolution, because it isn’t science. Its just couching observations in a framework.

Funny since Behe argue that Natural selection can ‘fail’. But what does he know…

So what is the ID hypothesis again?

I am also interested in David telling us more about the following claim he made

Parallel universes with different physics, universes which cannot be detected, and we just happen to be in a rare fertile one, versus intelligent design, many aspects of which are testable. Which of these is scientific?

Testable Intelligent Design aspects

David Heddle Wrote:

I did not say selection never fails, I said that the Theory of Natural Selection can never fail, it is sufficiently malleable that it can be adapted to any result.

Not true. There are many potential results that would not conform to the theory of natural selection, blending inheritance probably being the most famous of them.

Unless I missed something, the hypothesis was that there would be a bias in m/f births based on environmental conditions.

The hypothesis was that certain enviromental conditions would favor male offspring over female offspring. This is a phenomenon that has been demonstrated in many types of organisms. This paper is a metaanalysis of data from mammalian studies to see if this hypothesis holds true for mammalian reproduction.

Another way to put it: no outcome of Cameron’s study would have been recognized as a blow to evolutionary biology.

Correct, although it would have been seen as a blow to the TW hypothesis for mammals.

Nothing can shake evolution, because it isn’t science. Its just couching observations in a framework.

LOL. Please, David, tell us what your background is in evolutionary biology.

David Heddle writes

If the study had turned out the other way, would it have shaken any foundations? Caused any text books to be rewritten? Nope. Nothing can shake evolution, because it isn’t science.

What a laughable argument. Consider the following paper

http://www.geocomputation.org/2000/[…]22/Gc022.htm

“Terrain modelling and the impact of lava erosion in a neotectonic landscape: the case of the south west flank of Mount Cameroon, West Africa”

What if this study “had turned out the other way,” Mr. Heddle? Would we find you on some geology blog complaining that “Nothing can shake erosion, because it isn’t science”?

I didn’t think so. Why might that be? Because your religious beliefs aren’t “offended” by erosion (at least, no one has told you to be offended … yet).

Let me know if you have any other questions, David, and I’ll tell you where to go to find the answers.

Can any of you argue without getting snippy? It is true I know very little about evolutionary biology, I’m a nuclear physicist. And I am not into “creation science”. And I have not mentioned ID in this thread. What I have said is that what you are calling science, isn’t. It’s speculation that fits a presupposition. In that sense, it is on equal footing with ID. Both merely fit the data. Back to the physics analogy–its Galileo, not Newton.

David Heddle Wrote:

It is true I know very little about evolutionary biology, I’m a nuclear physicist. And I am not into “creation science”. And I have not mentioned ID in this thread. What I have said is that what you are calling science, isn’t. It’s speculation that fits a presupposition. In that sense, it is on equal footing with ID. Both merely fit the data. Back to the physics analogy—its Galileo, not Newton.

So you know very little about evolutionary biology, but you are sure that it is not science. I know very little about nuclear physics, but I am sure that it is not science, but a form of pedophilia.

Just claiming that it isn’t science does not make it so. It’s a hypothesis strongly supported by the observation. For instance see Endler on examples of Natural Selection.

ID is not even a speculation, it’s a negative argument based on ignorance. You hinted in another thread at testable ID. Curious minds would like to know what you are refering to?

David Heddle Wrote:

It is true I know very little about evolutionary biology, I’m a nuclear physicist. And I am not into “creation science”. And I have not mentioned ID in this thread. What I have said is that what you are calling science, isn’t. It’s speculation that fits a presupposition. In that sense, it is on equal footing with ID. Both merely fit the data. Back to the physics analogy—its Galileo, not Newton.

let me focus in a bit

Both merely fit the data

1st I fail to see how ID has any real theories that “Fit the data” 2nd isn’t that what sciense is about. Formulating theories that fit with the data. Even in your field the theories and laws are just ones that fit the data and there is a possibility that tomorrow or some other day we’ll find data that doesn’t fit the current laws and theories.

Saying

David Heddle Wrote:

the Theory of Natural Selection can never fail, it is sufficiently malleable that it can be adapted to any result.

May in a way be true to a point. But I’m sure that there where many theories in your field that where modified to take into account new found data without completely rebadging the originally theory.

If Charlie Wagners aliens land on earth and explain how they controlled all the living organisms of the earth tomorrow then evolution would be thrown out and we’d have a different label like “Alien modification of species”. But for now evolution is the best fit for the data. I’m sure other theories will come about that will refine it like P.E. but that doesn’t say the overall concept of evolution is wrong.

Now being a layperson myself I’ll let you scientists tell me if I’m in the wrong ball park here.

Reed, your comment

So you know very little about evolutionary biology, but you are sure that it is not science. I know very little about nuclear physics, but I am sure that it is not science, but a form of pedophilia.

is one of those that I am glad was made by an opponent rather than someone who agreed with me.

Pim wrote

ID is not even a speculation, it’s a negative argument based on ignorance. You hinted in another thread at testable ID. Curious minds would like to know what you are refering to?

You’d have to show me where I said that. In general, ID, like evolution, is not testable, although there are some claims to that effect in, for example, in the timelines of new species, extinctions, and in cosmology/astrophysics. In this thread I have not once argued for ID, just about how weak the claim is that evolution is science. This m/f bias, for example, comes down to, once again, stating that it is an “advantage” therefore its discovery supports evolution.

Now Wayne wrote, in response to my comment about “merely fitting the data”

1st I fail to see how ID has any real theories that “Fit the data” 2nd isn’t that what sciense is about. Formulating theories that fit with the data. Even in your field the theories and laws are just ones that fit the data and there is a possibility that tomorrow or some other day we’ll find data that doesn’t fit the current laws and theories.

ID of course perfectly fits the data, because everything can lay claim to having been designed, including the m/f bias. I agree this is not science, but just speculation. My point is the same criticism applies to evolution. I had the same feeling about evolution before I was a Christian and before I dabbled in ID–that as a scientist I didn’t find much science there at all. Genetics, yes, that is science. It is beyond refute that favorable traits will have an advantage. But to take that solid premise and run with it to the extent that is done takes you outside of science.

Even though it sounds plausible that the m/f bias evolved, how do you prove that? Is that it “smells right” sufficient? That wouldn’t work in physics (except now it is starting to work in physics, at least in cosmology).

Of course, theories in physics are supplanted, but they are testable and predictive. Science IS about more than just fitting the data, unless the theory of planetary motion based on epicycles is on the same footing as Newton’s gravitation. (By adding more epicycles one can even “explain” relativistic effects beyond the scope of Newton, so if merely fitting the data was sufficient the epicycle explanation would be better science than Newton’s gravitation.)

Wayne also wrote

If Charlie Wagners aliens land on earth and explain how they controlled all the living organisms of the earth tomorrow then evolution would be thrown out and we’d have a different label like “Alien modification of species”. But for now evolution is the best fit for the data. I’m sure other theories will come about that will refine it like P.E. but that doesn’t say the overall concept of evolution is wrong.

Actually I don’t believe that your aliens would do the trick, it would simply redirect the discussion to how the aliens evolved. But the fact that you have to resort to aliens makes my point. With Newton v. Einstein there are many tests we can perform to show that relativity is right. We don’t have to say “well if an alien landed and said he experienced the twin paradox then we would know Newton was wrong.” What is a definitive real test, with a plausible possible negative outcome, that can be done that to test evolution (not just genetics)?

Of course, by now you know or have guessed my position, but my argument is really independent of whether ot not I agree with evolution. I have not argued that evolution is wrong.

David, you have admitted that you know very little about evolutionary biology. Please explain how in a situation of such ignorance you can conclude that

  • evolution is not testable, and
  • there is not much science in it.

Furthermore, how can you even begin to compare evolutionary biology to physical mechanics if you know very little about evolutionary biology.

You have admitted to your ignorance, but you persist in believing that you negative opinion of modern biology has some merit to it. It does not.

This is what biologists have to put up with that physicists don’t; everybody thinks they know enough about biology to pass judgement on it.

BTW, proofs are for mathematics and philosophy. Science doesn’t “prove” anything with respect to the natural world.

Reed,

I believe I have answered your two points repeatedly. Once again, what is a definitive real test, with a plausible possible negative outcome, that can be done that to test evolution (not just genetics)?

With Quantum Mechanics, I can do an experiment on electron diffraction. If I don’t see it, then QM is wrong. That is science.

Science proves stuff all the time. For example, it has clearly proved that Newton’s theories are ultimately insufficient. It proved that Bohr’s model of the atom with electrons zipping around like planets is wrong. It requires (realistic) tests that prove something can be wrong. Maybe you meant that science cannot prove something is “ultimately” correct.

As for not being an expert in evolutionary biology, if being an expert as opposed to just being interested is a pre-requisite for posting here, then I’ll refrain.

This is what biologists have to put up with that physicists don’t; everybody thinks they know enough about biology to pass judgement on it.

Mostly true, but what David’s doing to biology here, also happens to people in physics. My stat mech professor was always getting calls from people explaining how their design for a machine violated SLOT and gave unlimited free energy. I wasn’t privy to those calls, but they might have started something like, “I don’t know a lot about physics, but the SLOT is wrong.…”

David Heddle Wrote:

I believe I have answered your two points repeatedly.

No you haven’t. You still haven’t explained how you are able to come to such universial conclusions about evolutionary biology if you are not familiar with it.

Once again, what is a definitive real test, with a plausible possible negative outcome, that can be done that to test evolution (not just genetics)?

This is where your ignorance gets you into trouble. Genetics is part of evolution. Before I continue, I want to know what you think “evolution” is. And then I can correct you where needed. It makes no since to try to explain to you how to test evolution, if you don’t know what evolution is.

Science proves stuff all the time. For example, it has clearly proved that Newton’s theories are ultimately insufficient. It proved that Bohr’s model of the atom with electrons zipping around like planets is wrong. It requires (realistic) tests that prove something can be wrong. Maybe you meant that science cannot prove something is “ultimately” correct.

Those are not proofs. Those are disproofs. Science is very much about disproof; however, it is not at all about proof.

As for not being an expert in evolutionary biology, if being an expert as opposed to just being interested is a pre-requisite for posting here, then I’ll refrain.

You do not have to be an expert to post here; just don’t expect to be treated with kid gloves when you insult my field in every post, just because you know very little about it.

Reed,

Of course genetics is part of evolution. I made that point, I didn’t deny it. I never claimed that adaptation though genetics does not occur.

So, by your argument, science, being incapable of proof, has not proved that the earth revolves around the sun?

No doubt my terminology is lacking. But I more or less equate genetics with micro-evolution. And by the generic term evolution I mean speciation.

An again, I haven’t said it is wrong. I said it is unfalsifiable, and hence not science. I apply the same criticism to the parallel universe theories that abound in my own discipline.

David Heddle Wrote:

So, by your argument, science, being incapable of proof, has not proved that the earth revolves around the sun?

This is correct. We have not proved that the earth revolves around the sun since it is possible, though not likely, that our observations leading to that conclusion are wrong. Because science always leaves open the possibility of revision, nothing is every proved.

No doubt my terminology is lacking. But I more or less equate genetics with micro-evolution.

What do you mean by “micro-evolution?” (Anti-evolutionists tend to use the term very differently than evolutionary biologists.) And what do you mean by “speciation?”

I said it is unfalsifiable, and hence not science.

How many years did you spend studying evolutionary biology, reading papers, reading textbooks, preforming experiments that lead you to this conclusion?

David,

You said, “And by the generic term evolution I mean speciation,” and, “ I said it is unfalsifiable, and hence not science.”

To echo Reed in the previous post, would you mind providing your working definition of “speciation”? By at least some widely held definitions, it’s occurring in abundance as we speak.

David Heddle: I said it [evolution, I guess - not sure] is unfalsifiable, and hence not science

Prior to the time we learned how to determine DNA sequences, evolutionary biology predicted that the pattern of DNA similarities among species would reflect the nested hierarchy of evolutionary relatedness. If the DNA sequences had contradicted that hierarchy, that prediction would have been falsified. The moral of the story is that “thus far unfalsified” does not equal “unfalsifiable”.

Reed,

You can continue to attack my credentials in biology and I will only agree.

Bob,

I would have to think about how to present my definition of speciation, because I don’t want to slide into an unproductive debate about whether or not species A evolved into species B. That is in fact an example of what is not scientific–plausibility arguments are not science.

Russell,

Fair point. I agree that if you disprove genetics evolution would go down with it. But what I am saying is that we all agree on genetics, but evolution is more than that, how do you falsify the aspects of evolution that go beyond genetics?

For example, the IDers would say the similarities arose from reuse of good design patterns. That’s unfalsifiable. Not science. So is the claim that environmental stress caused one species to branch into others.

Heddle: For example, the IDers would say the similarities arose from reuse of good design patterns. That’s unfalsifiable.

The real problem is that it is totally ad hoc. ID has no logically contrained designer. That’s the problem when invoking an entity who we just do not understand or can predict.

I am still interested in these testable hypotheses of ID…

I have stated my complaint many times: some speculation is tolerated in publication, other speculation isn’t. It’s that simple. The highly regarded papers I referenced contain speculation. They are deemed acceptable. Fair enough. I only have a problem with the absurd claim that ID has a level playing field. It doesn’t. And I even agree it shouldn’t. But it is elitist or naive to claim it does.

One view of evolution is the change of one animal type to another as in a fish becoming a lizard. This is so bogus.

Is it more or less “bogus” than an argument that lizards evolved into insects, Elvis? And why?

Oh, and Mr. Heddle: feel free to jump in here. You just might be able to handle this one.

I only have a problem with the absurd claim that ID has a level playing field. It doesn’t. And I even agree it shouldn’t. But it is elitist or naive to claim it does.

OK. What we have here is a not very interesting question of semantics. The folks who originally raised the sports analogy of an uneven playing field were trying to make a case that the deck was stacked against them. (To use a sports analogy more in keeping with my lifestyle). I.e., that The Establishment was being “unfair” in some impeachable sense. THAT’s what I am calling bogus.

Is that not the sense in which that complaint was raised? And do we not all agree on the bogosity of that complaint?

“Speculations” on the nature and behavior of oxygen are, and should be, much more acceptable in a modern chemistry journal than speculations on the nature and behavior of phlogiston, to use RBH’s analogy.

David,

Again - what exactly do you consider to be lower organisms?

GWW’s shameless monster “does, however, continually emit the synthesizer track from song “905””. I don’t remember the Who. I think I must have gone direct from the 1960’s, when a most vivid dream that Collembola are closet crustaceans frightened me off biology for ever, to the 1980s.

I pity the shameless monster. It’s not needed. http://www.forteantimes.com/ gives us all the evidence that’s needed by way of flying pigs, women giving birth to rabbits and so on, to disprove the theory of evolution (and much else) many times over. Our ID friends really should make more use of this wonderful resource.

But they’ve got into a rut with all this statistical stuff. I have tried and tried to understand the point of this but the answer always comes out “er .… so?” I accept that that’s my problem but it doesn’t really help when other contributors post (in so many words) that I’m not qualified to understand the maths, even when that is probably (p= (p

Bob Maurus Wrote:

David,

Again - what exactly do you consider to be lower organisms?

I hope it’s not archaebacteria and eubacteria, as that would suggest that he misunderstands evolution even more than I thought.

David, to give you an idea, the evidence for common ancestry of, say, humans, dogs and cats, is so overwhelming that it even has some ID strategists conceding it. OTOH, the biochemistry of archaebacteria and eubacteria are so different from each other that some mainstream scientists think that they arose independently.

But here’s the key difference between mainstream scientists and the “big tent” pseudoscientists. The former debate openly, while the latter want to cover up their differences in favor of misrepresenting evolution.

Well I’m an IDer like David, so if that means you write my comments off before I even begin, so be it.

It seems to me that some (at least) of the disagreement could be cleared up with better semantics. Specifically, what do we mean by “science”?

This word has evolved (!) over the years, and still has different meanings to different people. For example, in the middle ages theology was considered the “queen of sciences”. I doubt many people today would consider theology a science.

An older friend of mine is a psychologist and he insists that psychology is a science because of its empirical nature.

Some people regard history as a science. Others would place it in that nebulous sphere called “the humanities”.

I’ve just realised that I am a scientist too! I have a bachelor of science from a reputable university. It is in computer science.

All of these “sciences” are very different to the nuclear physics of Dr Heddle, or the biology of this thread. Lets get an agreed definition of science and then the question can be answered.

David Heddle Wrote:

ID of course perfectly fits the data, because everything can lay claim to having been designed, including the m/f bias.

Sure the generic idea of ID does but it isn’t a “Theory”. ID promoters are saying that it is a “Theory” but have not shown any valid work of being a theory. I can say that multidimensional microbes control everything in our universe but it would hold about as much weight as the current ID hypothesis. The fact that many Christians hold faith and want to believe in the bible does not make the 6,000 year old Hebrew poetry true.

You keep make references to your field of expertise being science but evolution not being science. I ask you how can you say that? Have you seen a star evolve from start to finish? No you infer much of what you know by observing many little pictures and putting the pieces together. You don’t understand biology and then say it is not science. Lets take a look at one reason why evolution is supported by main stream science. Most of our development of drugs relies on common origin. The fact that we know that a reaction in animal x will be similar to a reaction in animal y (of which humans could be) therefore we can develop drugs without having to immediately testing it on humans. Genetics is one of the biggest indication of common origins and therefore evolution. None of this is incompatible with a “GOD”. Some choose not to believe, some sit on the fence waiting for more evidence (like me), some choose to believe.

David Heddle Wrote:

Actually I don’t believe that your aliens would do the trick

David please read carefully I said “If Charlie Wagners aliens land”. I don’t personally hold on to Charlie’s beliefs because of the reasons you stated.

David Heddle Wrote:

What is a definitive real test, with a plausible possible negative outcome, that can be done that to test evolution (not just genetics)?

There are test that would have shown evolution false. Just the fossil records being organized as it is. The fact that life in the fossil record generally gets less complex as we go back in time. You don’t argue with radiometric dating do you David? Now given those 2 sources the 2 most compelling answers is a) all life has a common origin or b) God created life billions of years ago then after a long wait created some multi-celled life then a bit later created some more creature.…over the last few hundred thousand years god created a bunch of different homo species altering the design just slightly.

Now note that A is not incompatible with God. B how ever says “God can not create a species that adapts to it environment but must actually redesign the species”

In truth evolution would suggest a smarter “God” then ID’s hypothesis that species can not evolve, blah blah blah.

David Heddle Wrote:

Yes—that works for me. Keep in mind that I do not deny that speciation occurs in lower organisms.

Ok David let us take Zebra’s a member of the genus Equus. Lets look at 3 species of Zebras. Mountain, grevy and plain zebras. They all have their stripes and outwardly you might think they are 1 species but in fact they differ greatly in genetic makeup. They can interbreed and depending on the combination of mother and father have different viability rates. This is kind of like donkeys can horses interbreeding and producing mules. The difference, and a good one is, interbreeding of horses and donkeys is very viable with a high birth rate yet these hybrids are normally sterile. With Zebra’s interbreeding has a much lower success rate because of the genetic differences. You can read this as donkeys and horses are more closely related then mountain zebras and Grevy’s. Equine s are a great living example of evolution and divergence. The equus genus is very well documented in both the fossil record. Lets look at this

Hyracotherium is a small 1’-2’ equus with legs with 4 toes on the front 2 legs and 3 on the hind legs HYracotherium has a nice smooth transition to Orohippus. We see the loss of the 2 vestigial toes (they originally had 5 on all legs) and major change in the teeth due to the tougher plants that they would have been eating. Mesohipuus lived during a drying period where forests where receding and grasses where starting to appear. This favored equid with longer legs as they where out in the open more often. This species started to loose more toes but became taller. Miohippus has a longer face then the earlier equids and the ankles of this species started to change. Miophippus and mesohippus actually co-evolved much like today’s zebras do for about 4 million years. Miohippus divided into 3 lines, the anchitheres, the archeohippus and miocene. Miocene horses had evolved even more specialized teeth for chewing grass (you wouldn’t think that it would be that hard would you). They also became better runners via increased size, length of legs. Their faces got longer. Their leg bones favored fusing because of the advantage of running. They, for the same reason, lost the ability to rotate the legs. Their feet further evolved so they where constantly on their toes, or more accurately at this point 1 central toe, making them faster, ever wonder where that saying came from?

At this point we are still over 24 million years ago. The equids still have toes but have evolved into grazers and being spring footed.

Blah blah blah.…

The evidence is overwhelming Here are a few links

PBS - The Origin of the Horse Equine Studies Institute Evolution of the Horse Horse Evolution

If evolution is not true then why do we see many species able to interbreed to varying degrees of success?

Wayne,

Don’t forget lions amd tigers, which don’t interbreed in the wild, but do produce fertile offspring when crossbred in captivity. I had hoped David would answer my question, so we could establish some operable parameters, but I guess that was not to be.

I’ve seen the general shape of David Heddle’s arguments before, and these are usually clarified (after the usual runaround) into a distinction between “experimental” and “descriptive” science. The argument then holds that “descriptive” sciences (like cosmology, astronomy, geology, evolution) aren’t “real” sciences because they make no predictions, except the very weak prediction that the general pattern derived from observations so far, will tend to be followed by observations in the future following this same pattern.

However, if future observations do NOT follow the predicted pattern, the “theory” is none the worse; it’s simply extended or modified to accommodate the latest observations. Since the name of the theory didn’t change, the presumption is that the theory itself didn’t change, and therefore cannot be falsified.

But in reality, there is no such thing as a purely descriptive science that makes no predictions. Astronomers are just observers, but telescope time is dear indeed. Examinations of the universe aren’t made at random; theory guides them. David Heddle, like most people shaping such an argument, doesn’t seem to realize that there is no qualitative difference between a lab experiment and a paleontological expedition: Both are attempts to create circumstances by means of which predictions can be supported or rejected. The only difference lies in whether the experimental circumstances are managed by people or by natural (i.e. not managed by people) circumstances.

And so, if the nuclear physicist with his atom smasher creates a “theoretically impossible” particle, or if the paleontologist finds a human skeleton in a Jurassic stratum (and observational errors can be ruled out), both scientists must do some very serious re-theorizing. In each case the predictions contrary to observation are real and critical.

This thread, unfortunately, never passed the “runaround” phase. We still have no clear idea what Heddle means by evolution, or lower organisms, or microevolution. The important notion of “scientific proof” was raised, but left unresolved. Craig’s excellent question about just where the boundaries of science lie was simply ignored, but as the rather embarrassed holder of a “political science” degree, I find this more than a semantic issue.

Human Cells Revert to Embryo State, Scientists Assert

Should we be diving into this area?

It is very touchy ground. While we have the ability to clone sheep and cows the current technology is far from what we need for primates. With dolly, the cloned sheep, there where almost 300 attempts made. Can we allow the same situation to happen with humans? I’m not talking a religious issue here but just basic human rights. Should we be able to test this type of stuff on our closest relative the chimpanzee? There is actually a legal movement going on to give the great apes the equivalent of human rights. In places like New Zealand it is illegal to do tests on great apes without their promission if the test does not benifit their species. Good thing they have a good population of signing great apes that regularly agree to different psychological testing.

Anyway I’v heard rumors about naturally occuring hybrids though I’ll believe it more when I see the evidence. I do know about artifical hybrids embreos using Human DNA and both Pig and Cow cells. I wouldn’t doubt that some lab some place tucked away from public eyes is trying to perfect the process. But the thing is it might not come into public view sinse there is slim chance that they could obtain pattents.

anyway 1 am.…time for me to goto bed.

Physics is often idealized as the model of science, it’s practitioners idealized as model scientists. That’s wrong. Sciences accomodate their subject matter. Their methods and practices necessarily differ. Creationists who want to disparage biology and evolution by comparing it to physics make this mistake. Anyway, I see nothing in evolution which is as problematic as the sheer incompatibility of Quantum Mechanics and General Relativity.

This is something I’m working on:

When compared to physics biology is messy and hard. For a physicist to do something similar to biology they would have to ask “what have the exact positions of this particle been for the last million years.”

Reed,

Would that make W a biologist wanna-be? He did a lot of whining last week about how hard his job is - and he’s certainly made a mess of things! :^)

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This page contains a single entry by John M. Lynch published on August 23, 2004 2:34 PM.

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