Feedback for August 2002

Well, you're missing a couple of things...but that's OK, lots of people don't quite grasp them, so it's no point against you.

One thing is that sometimes biology works exactly as you describe in your example, adding something in development that isn't wanted in the final form, so an extra step is added to knock it off. An example that comes to mind (you can read more about it in Peter Lawrence's The Making of a Fly) is the way Drosophila neatly packs a spatial determinant protein called hunchback into her eggs, which if left in place, causes serious abnormalities in early development...so she also localizes a bit of another protein called nanos that specifically destroys the misplaced hunchback. You'd think it would be simpler to just not bother adding the maternal hunchback in the first place, but that's the way evolution often works, cobbling together something that works, even if it's not the best way.

The other thing is that I think the General Anti-Creationism FAQ where you got that quote is a bit too terse and vague on that point. We do NOT think that embryos repeat their evolutionary history in development. What has been observed is that all embryos go through initial steps in development in which they simply produce lots of cells and then separate out primitive tissues that migrate in gastrulation; these steps vary superficially in different groups. These generic early steps then all converge on a simple, general form that is conserved within all the embryos within a phylum. Vertebrates, for instance, build a central notochord, put a strip of nervous tissue on top of it, and add a few other features, like pharyngeal arches and a tail. Subsequent development then adds details that vary in different species.

It's not recapitulating its history. The embryo is building a general plan first, then sculpting it into specific forms. Think of it as a kind of rough sketch that gets refined with time, and all organisms that have a similar body plan are rather indistinguishable at that rough sketch stage.

Hint: the origins of the earth is not a matter for evolutionary biology.

I would laugh, too. I don't know who to laugh at, though -- I don't believe that crop circles are made by aliens, and I don't know of any of my fellow evolutionists who believe that they are. Your comment here is simply bizarre and unrelated to evolutionary thinking. I could just as well argue that creationists are wrong because they believe that teddy bears are possessed by demons...when no creationist that I know of has made such a claim.

As to your questions:

Lamarck believed in the continuous spontaneous generation of the very simplest life forms at all times, and that each of these would then ascend a ladder of complexity or grades of organisation. Darwin, to the contrary, suggested in the Origin that there were a "few forms, or ... one" at the beginning of life and that all subsequent evolution occurs by diversifying those forms. In a letter he supposed that there might have been a single form in a "warm pond", but this was speculation only.

Darwin's conservative approach has, again, proven to be inadvertently prescient. There are suggestions that there is no single root to the Tree of Life, but that early on genes were exchanged rather promiscuously. However, one thing Darwin also noted is that should a new abiogenetic event occur, the products would most likely quickly be gobbled up by the more efficient already-evolved lifeforms, and we'd never see them.

As to the origins of the universe and evolution, if we leave to one side all kinds of grandiose Cosmic Evolution scenarios and philosophies, the main impact of the universe's history on biological evolution seems to lie in the processes that generated heavier elements (including carbon, nitrogen and so forth) and thus allowed the formation of complex organic molecules in space and on earth. I understand that there is a growing consensus that a lot of the initial organic material was deposited on earth by coments during the Great Bombardment.

However, if the universe was formed in two seconds shortly before the first life appeared, while that would cause trouble for cosmologists, it would not affect evolutionary biology.

As to your question about “nonliving substances”, the short answer is that natural selection doesn’t apply to them; though there are selective processes that can occur in nonliving matter, pebble sorting on a beach for example. For natural selection in the Darwinian sense to occur you have to have some sort of self-replicating “organism” (or proto-organism), which makes occasional mistakes in the process of making copies of it’s self.

I don’t know why you would think that natural selection should apply to nonliving things unless you’ve been confused by anti-evolutionists frequent conflation of all mainstream science with evolutionary biology.

While it is true that physicists and astronomers might speak of the “evolution” of matter or stars they are using the term simply to describe a process of change, the details of which being quite different from those involved in biological evolution (descent with modification).

In the case of the heavier elements (heavier that hydrogen & helium) these are thought to have been formed within stars, particularly within supernovas. Perhaps one of the volunteers better versed in the physical sciences can expand on this. Baring this, see the Supernovae, Supernova Remnants and Young Earth Creationism FAQ by Dave Moore for more on this.

It is often not understood by many people that molecules do not all have the same structure even if their elements are the same. There are many forms of a single molecule that can exist, and in the case of a protein that is 100 atoms long there can be up to 10⁹⁰ possible shapes formed. Most of them do not get so formed, but the point is that there are many differently shaped versions of the same molecule.

Now, suppose that a molecule is formed in such a way that it naturally falls into a particular shape in the processes of nearly-living chemical reactions, whatever they were. It will have certain properties and these will regulate the rate of the reaction (and hence the rate at which it copies itself), and the efficiency of the "capture" of the raw "food" molecules (the monomers, as they are called), that are needed to continue the reaction. Any variant which can increase either of these two properties in that reaction will tend to get copied more and so "take over" the soup in which they are made.

This is, in effect, a natural selection process on nonliving substances. It will result, if conditions are right, in chemical processes that are more complex, and better "adapted" to the conditions in which they find themselves. I believe that natural selection is an instance of a universal tendency of things that are dynamic and make copies of themselves, whether or not they are "alive".

Although the theory of natural selection is not supposed to apply to the elements themselves, there is a form of selection due to the creation of heavy elements in novas and supernovas that explains why we are made of the elements we are.

The reason for this is that the very early earth is much more fluid than it is now, as if the whole planet were a kind of ocean. It is easily deformed, and that deformation is what drives the moon's recession. Today, the solid body tides of the much less pliable earth are not that important, while the deformable, fluid part of the earth is the global ocean. By the time the earth is a billion years old, that situation is long gone already.

But while the flexible early earth, more or less round, was evenly deformable in all directions, the ocean is not. Its deformation is contaminated by continents, which determine the shapes of the seas by their positions. If the size of the body of water in an ocean or sea is approximately the same as the size of the wave induced in the water by the moving moon, then a condition of "resonance" will set in, causing the interaction of moon and ocean to be much larger than it would have been, were the ocean a different size.

That condition of resonance is at work today, hence the current recession rate is anomalously fast, compared to times when the oceans did not have such a favorable shape and size. Hence, when you look at the "Paleontological Evidence" section of my article, there are recession rates only a third of what we see now. That's because there is no favorable resonance at that time, and the earth is by then far too old for the fast rates found only in its infancy.

(A good source for interesting up-to-date science stories is "Nature Science Update", a weekly email service available from www.nature.com.)

They may be receptive to stories from people who share more of their views, such as the personal stories on Glenn Morton's website.

Eldredge and Gould based "punctuated equilibria" on Ernst Mayr's theory of allopatric speciation of peripheral isolates. The PE FAQ (linked above) goes into this in some detail.

Wesley

Some plants produce honeydew or small edible bodies that attract ants. The ants then defend the plants against other herbivores.

In other cases, such as asparagus sprouts, the parts are edible simply because the plants have not produced defenses against herbivores such as us. Most defenses are metabolically costly, so plants could grow more rapidly without them. In some cases, the tradeoff favors growing rapidly at the risk of being eaten.

As bats can be traced in the fossil record as far back as the Eocene (54-34 Mya), the split from primate precursors must have occurred at least that far back, perhaps in the Paleocene (67-54 Mya). See sections 1B and 2A of the Transitional Vertebrate Fossils FAQ.

Evolution is based on evidence from the earth itself, including evidence that is a heck of a lot less ambiguous than anything in a human language. Christianity, as I understand it, says God had something to do with the creation of the earth, and therefore He is responsible for that evidence. If evolution is false, then God cannot be trusted. And if you can't trust God, then what good is the Bible?

2) The suns energy is not decreasing, the data to which you allude do not exist. Theory requires the sun to be slowly expanding & brightening, though much too slowly for us to observe. On shorter time scales, the sun's brightness varies more or less periodically.

3) The integration of probability with entropy is fundamental and necessary in physics. The attempt to argue that this should not be done is naive at best. As for Borel's law, it does not apply, since it deals with random probabilities, whereas we are dealing with systematic events with skewed probabilities. Also, see the Borel's Law FAQ.

4) Not at all true, not even close. No stretch of the imagination can justify such a silly notion as "nothing X time X chance = life", and no aspect of any evolutionary theory does so. Creationists, on the other hand, regularly invent the claim that it does, since it frees them from the necessity of thinking about what evolution really is.

Consider this our little intelligence test.

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Have fun.

At one point in the history of science, creation was a viable scientific explanation. That ceased to be the case around 1800, and ceased to be even possible around 1858. As much as we would like to be "even-handed", honesty and science comes first. Sorry.