What prevents macro-evolution?

[Crispy Duck]

Hi all,

Here's something that occurred to me that other day, which I haven't seen raised on talkorigins or similar sites. According to the Intelligent Design crowd, what is it that prevents macro-evolution?

I remember reading a very important statement about evolution - it was probably in a Dawkins book, though I don't remember which one. The statement was that, given *any* system in which you have (i) reproduction, (ii) inheritance, and (iii) random mutation, there *has* to be "evolution" - it can't be avoided. The average characteristics of the replicators, whatever they may be, will inevitably drift away from their starting points, particularly if anything in the environment changes.

This statement, that any system of replicators will inevitably evolve, seems self-evidently true to me. There is no mechanism whereby a given generation can "remember" the limits of its parent's generation, and cause its own offspring to remain within those limits.

Intelligent Design posits that macro-evolution doesn't (or possibly can't - which is it, by the way?) happen. So, what's stopping it? Has the ID movement been challenged to hypothesise a mechanism that limits genetic drift? Would they just fall back on their abuse of information theory?

I'm tempted to invoke the Second Law of Thermodynamics and suggest that any system of replicators that somehow *didn't* drift would have to violate it, but I don't want to get into such dubious territory...

I'd be interested in the thoughts of those more knowledgable than myself...

cbl.

 

[Bronze Dog]

Since I have a feeling hammy's coming: Can someone please define "macro-evolution"?

 

[KingMerv00]

Welcome to the forum.

I'm fairly certain that this was discussed on talkorigins at some point but I can't remember where exactly.

Anyway, the closest thing I've heard to an attempted refutation is "mutations are too slow", "the mutations would be too complicated", or "the intermediates would have no survival advantage". You know, stupid stuff.

 

[KingMerv00]

Since I have a feeling hammy's coming: Can someone please define "macro-evolution"?

Maybe he doesn't know who hammy is. For his sake, I hope it stays that way.

 

[cbish]

what is it that prevents macro-evolution?

I'd say the same thing that causes it; Natural Selection.

I don't know if macro-evolution can be prevented. I know many organisms have changed very little but that is usually at the Family level of classification. At the species level, organisms that are "unchanged" have actually changed over time.

 

[PatKelley]

"Macro evolution" would be one "kind" crossing over to being another "kind"- where creationists/ID claims there is no middle ground, or a half-formed wing is useless and so on, so there is no way competetive advantage could favor a half-formed crippled transitional animal.

Except that selection does not operate in this manner, and modification of body parts is not spontaneous generation. A good argument against evolution would be if extra limbs evolved.

Allow me to give a demonstration:
A boneless fish starts out with a skin protrusion (mutation) that confers a competetive advantage (camoflage)
A few lengthened become sensory filaments (sense) became barbs (sense and defense) became calceous spines (defense) became moveable spines (defense) became hard fins (mobility and defense) became bony fins (mobility). This is a rough and unresearched recapitulation of a possible evolution of bony fins.

The problem is that ID/Creationism would demand that at each step, from start to finish, that the only use be movement. That's not how evolution progresses: parts are parts; they are not "destined" for a final form.

 

[WildCat]

If the question is how one species begets another species, I think that isolation has to be present. That is, one population can have no interbreeding w/ any other population. Since their mutations would likely be mutually exclusive after separation, eventually the genetic differences would cross the species threshold. I'll define that as no fertile offspring.

 

[RichardR]

Hi all,

Here's something that occurred to me that other day, which I haven't seen raised on talkorigins or similar sites. According to the Intelligent Design crowd, what is it that prevents macro-evolution?

There's a magic invisible barrier. Micro evolution OK. But the magic barrier prevents macro evolution.

I think that's it.

 

[Crispy Duck]

Thanks for the replies. I know who Hammy is - I would be very interested to hear his views on the question.

I understand the definitions of micro- and macro-evolution, as given by ID. I can also see the paucity of their arguments against evolution, and I'm perfectly happy in my own mind that evolution adequately explains the origin of species.

My point in raising the question was this: it seems to me that in most cases, IDers don't put forward any ideas of their own, and simply say "I can't see how evolution can explain feature X, therefore God did it". They seem to accept, as micro-evolution, that any system of replicators must drift away from its starting point. However, they draw an arbitrary line at "macro-evolution". It therefore falls fairly and squarely on ID to explain what special feature of the specific system of replicators in question, DNA-based life, prevents macro-evolution.

I know this question has been raised - "how much accumulated micro-evolution counts as macro-evolution?" etc - but I found it very useful to have my way of thinking about the systems turned upside down. I suspect that many ordinary people have the implicit impression, as I once did, that there is some special magic ingredient in DNA, or the environment, or somewhere, that somehow causes or allows evolution to happen. Turning that around, and demonstrating that it would be impossible for evolution *not* to happen, is a very important "paradigm shift", if you'll excuse the manamgement-speak.

I look forward to hammy's thoughts...

cbl.

 

[sphenisc]

Thanks for the replies. I know who Hammy is - I would be very interested to hear his views on the question.

I understand the definitions of micro- and macro-evolution, as given by ID. I can also see the paucity of their arguments against evolution, and I'm perfectly happy in my own mind that evolution adequately explains the origin of species.

My point in raising the question was this: it seems to me that in most cases, IDers don't put forward any ideas of their own, and simply say "I can't see how evolution can explain feature X, therefore God did it". They seem to accept, as micro-evolution, that any system of replicators must drift away from its starting point. However, they draw an arbitrary line at "macro-evolution". It therefore falls fairly and squarely on ID to explain what special feature of the specific system of replicators in question, DNA-based life, prevents macro-evolution.

I know this question has been raised - "how much accumulated micro-evolution counts as macro-evolution?" etc - but I found it very useful to have my way of thinking about the systems turned upside down. I suspect that many ordinary people have the implicit impression, as I once did, that there is some special magic ingredient in DNA, or the environment, or somewhere, that somehow causes or allows evolution to happen. Turning that around, and demonstrating that it would be impossible for evolution *not* to happen, is a very important "paradigm shift", if you'll excuse the manamgement-speak.

I look forward to hammy's thoughts...

cbl.

Perhaps you could provide evidence of the claims you make about ID, specifically

a) that macro-evolution is prevented

b) It simply says "I can't see how evolution can explain feature X, therefore God did it".

 

[sphenisc]

Since I have a feeling hammy's coming: Can someone please define "macro-evolution"?

Here's a clue : Google "definition" "Macro-evolution"

 

[Crispy Duck]

Perhaps you could provide evidence of the claims you make about ID, specifically

a) that macro-evolution is prevented

b) It simply says "I can't see how evolution can explain feature X, therefore God did it".

Hmmm... good challenge. I can't be bothered looking up specific references; everyone reading this thread knows what I'm talking about. Proponents of ID have claimed, amongst other things, that bacterial flagella and the blood-clotting system are too complex to have evolved via the accepted process of micro-evolution, and that therefore must have been intelligently designed (by God). They also claim that the accepted process of micro-evolution could not have allowed a common ancestor to diverge into both humans and chimps, or both fish and whales, or both animals and plants.

This goes back to the parenthetical question in my first post - do IDers claim that macro-evolution can't happen, or simply that it hasn't happened? Or are you implying that IDers believe macro-evolution (ie speciation etc) can and does happen?

 

[sphenisc]

Hmmm... good challenge. I can't be bothered looking up specific references; everyone reading this thread knows what I'm talking about. Proponents of ID have claimed, amongst other things, that bacterial flagella and the blood-clotting system are too complex to have evolved via the accepted process of micro-evolution, and that therefore must have been intelligently designed (by God). They also claim that the accepted process of micro-evolution could not have allowed a common ancestor to diverge into both humans and chimps, or both fish and whales, or both animals and plants.

This goes back to the parenthetical question in my first post - do IDers claim that macro-evolution can't happen, or simply that it hasn't happened? Or are you implying that IDers believe macro-evolution (ie speciation etc) can and does happen?

I appreciate your honesty. Though, if you're unwilling to support the accusations you've made, don't be surprised if others can't be bothered to answer your questions. I'm saying that I don't believe your claims because a) ID specifically avoids any reference to God, b) I've seen no ID description which refers to a macroevolutionary 'barrier'.

What IDers believe is up to them, as far as I can see there is nothing in ID which procludes macroevolution.

 

[Paul C. Anagnostopoulos]

Picture evolution as trajectories through phenotype-space. Phenotype-space has millions, perhaps billions, of dimensions. A particular species traces a path through this space. A new species forks from an existing one, first on a path that is closely parallel to the original, and then on a path that diverges more and more as time passes. At some point the distance is great enough that we talk about a new genus, family, etc. The distances that make us talk of new taxonomies are quite fuzzy.

The environment puts constraints on the trajectories through phenotype-space. In fact, most points in the space are not viable; there are many more ways to be dead than to be alive. Some IDers claim that there is another contraint on the trajectories, that something prevents two trajectories from diverging further than a certain distance in phenotype-space. Does anyone have a clue how such a constraint might work?

~~ Paul

 

[Roboramma]

I appreciate your honesty. Though, if you're unwilling to support the accusations you've made, don't be surprised if others can't be bothered to answer your questions.

Sphenisc. I think it's quite cool that you're sticking up for the ID side of the argument. It's very easy for a group of people who all agree to let little falsehoods slide by, or not even notice them. So cool.
Anyway, to the above, I think he'd be more willing to support his accusations if you were to say exactly what you think needs to be supported. Do you suggest they are false, or simply that he hasn't given the evidence necessary to determine whether they're true?

I'm saying that I don't believe your claims because a) ID specifically avoids any reference to God,

Except when they're talking to believers.

b) I've seen no ID description which refers to a macroevolutionary 'barrier'.

What IDers believe is up to them, as far as I can see there is nothing in ID which procludes macroevolution.

Well, I don't know whether that's true or not. But I don't think the argument requires that they do. Here's how I see it.

Macroevolution is inevitable. Given enough time any population of reproducing organisms will diversify into a mirade of life forms, occupying many different niches, each well adapted to it's life. (that is, if they don't all go extinct first), or are out competed in all niches but the one to which they are well adapted by other organisms that do follow this general pattern.
Many will evolve complex structures. While ID might argue that some specific complex structures cannot evolve, they cannot suggest that none could. Many would, in fact. Some would even evolve to the point that we wouldn't able to say what exactly was the evolutionary pathway that brought them about.

This is exactly the way we see the world. The fact that we can't explain every adaptation right away should be expected.

 

[Hawk one]

I'm saying that I don't believe your claims because a) ID specifically avoids any reference to God,

Oh, do they now?

 

[PatKelley]

Perhaps you could provide evidence of the claims you make about ID, specifically

a) that macro-evolution is prevented

Try this quote on for size, as it's both from the DI and a recent article referring to Dover.

And they generally have no problem with much of evolutionary theory, which can — in part —be stated as the change of species over time. The fossil record, they agree, amply bears out this observation, which is known as micro-evolution.

Where they dissent is in what’s known as macro-evolution — the transformation over time of a species into another species. The distinction is drawn in “Of Pandas and People: The Central Question of Biological Origins,” the alternative text endorsed by the Dover school board:

“Intelligent design means that various forms of life began abruptly through an intelligent agency, with their distinctive features already intact — fish with fins and scales, birds with feathers, beaks and wings. Some scientists have arrived at this view since fossil forms first appear in the rock record with their primitive features intact, rather than gradually developing.”

-(emphasis added)

That would appear to fit the bill for "macro-evolution is prevented."

b) It simply says "I can't see how evolution can explain feature X, therefore God did it".

Well, let's just see...

In other words, their argument is not so much with evolution per se as it is with what they see as the failure of evolution to account for how it all started. It is perfectly reasonable as science, they believe, to explore whether an outside agent triggered diversity of complex biological structures seemingly engineered to sustain life on Earth.

It assiduously, in this press release, avoids saying "God" but does assert that "Intelligentagencydiddit" for what they view as differences between species i.e. purported targets for "macroevolution" which they reject.

 

[Crispy Duck]

From the Discovery Institute's "Top Questions and Answers about ID":

3. Is intelligent design theory incompatible with evolution?
It depends on what one means by the word "evolution." If one simply means "change over time," or even that living things are related by common
ancestry, then there is no inherent conflict between evolutionary theory and intelligent design theory.

(For some reason, I'm not considered worthy to post links).

So I must admit, Sphenisc, you're right that ID, or at least one part of the Institute's website, does not deny macro-evolution. To me, this is even more bizarre. Can it really be the case that IDers accept that everything that has ever lived on this planet was the product of random mutation and natural selection, with the specific exceptions of flagella and blood clotting?

Curiouser and curiouser.

 

[Paul C. Anagnostopoulos]

And the eye. Don't forget the eye.

~~ Paul

 

[sphenisc]

Oh, do they now?

ID theory/conjecture is distinct from 'the ID movement', point 1) of this site attempts to confuse the two, as does your use of the word 'they'. What IDers do in the privacy of their own publications is up to them, I'm talking about ID theory.

point 2) refers to legislation on educational standards, this is not part of ID theory.

point 3) I'm pretty sure that IVP will publish the book of Esther, that doesn't mean that it contains any reference to God.

point 4) Again a reference to the ID movement, not ID theory.

point 5) "ID is blatantly anti-religious if the religion is one they disagree with." Again a switch (mid-sentence!) from discussing ID theory to IDers.

None of the points on this site support the claim that ID theory avoids specific reference to God.