The Dawkins question, new "information" in the genome?

There's a bazillion examples of this, some of which Dawkins supplied; that portion of his response was cut from the interview in which he appears.But the process that addes novel genetic sequences to genomes is random mutation. The process that causes those sequences to come to dominate the genome, or to be extinguished from it, is natural selection. Why? I will grant you that metazoan life requires additional genetic sequences that a simpler form of life would not have; does that neccessitate additional genetic information? Since I don't know what "information" is supposed to be, you tell me. Obviously, and that must be due to genetics, but it's a considerable leap to propose that that difference is due to the "amount" of some kind of hypothetical "genetic information." Usually, there's almost no correlation between the complexity of an organism and the length of its genome. Generally, as an adaptation against predation, like in this example of colonality arising in a blue-green algae:

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Coloniality in Chlorella vulgaris

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Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.

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(Emphasis added by me.)That's my favorite example, because it shows how multicelluarity can arise spontaneously as an adaptation to predation. The next step from colonality is specialization of cells; there's a great deal of transitional steps that survive in the invertebrate kingdom. For instance, sponges have only three types of cells. Random mutation and natural selection. The selection pressure is predatory.

I don't think anyone has. The conclusions of science, and evolution is such a conclusion, are always tentative. We say "we are confident this is the most accurate model at this time, but we're ready to revise it in the light of new data." No amount of fossils will make the theory more "certain", because that's not how it works. The theory of evolution, like the germ theory of disease or the theory of gravity, will always stay tentative.But each new fossil we find - and we have a lot of fossils - lends further support to the theory of evolution.

Well, there's this on the genetic basis of eyes in jellyfish:

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The Sine oculis/Six class family of homeobox genes in jellyfish with and without eyes: development and eye regeneration.

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Stierwald M, Yanze N, Bamert RP, Kammermeier L, Schmid V.

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Institute of Zoology, University of Basel, Biocenter/Pharmacenter, CH-4056 Basel, Switzerland.

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The development of visual organs is regulated in Bilateria by a network of genes where members of the Six and Pax gene families play a central role. To investigate the molecular aspects of eye evolution, we analyzed the structure and expression patterns of cognate members of the Six family genes in jellyfish (Cnidaria, Hydrozoa), representatives of a basal, non-bilaterian phylum where complex lens eyes with spherical lens, an epidermal cornea, and a retina appear for the first time in evolution. In the jellyfish Cladonema radiatum, a species with well-developed lens eyes in the tentacle bulbs, Six1/2-Cr and Six3/6-Cr, are expressed in the eye cup. Six4/5-Cr is mainly expressed in the manubrium, the feeding, and sex organ. All three Six genes are expressed in different subsets of epidermal nerve cells, possibly of the RFamide type which are part of a net connecting the different eyes with each other and the effector organs. Furthermore, expression is found in other tissues, notably in the striated muscle. During eye regeneration, expression of Six1/2-Cr and Six3/6-Cr is upregulated, but not of Six4/5-Cr. In Podocoryne carnea, a jellyfish without eyes, Six1/2-Pc and Six3/6-Pc are also expressed in the tentacle bulbs, Six1/2-Pc additionally in the manubrium and striated muscle, and Six3/6-Pc in the mechanosensory nematocytes of the tentacle. The conserved gene structure and expression patterns of all Cladonema Six genes suggest broad conservation of upstream regulatory mechanisms in eye development.

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Or this, on the evolution of eyes:

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Eyes: variety, development and evolution.

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Fernald RD.

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Neuroscience Program, Stanford University, Stanford, Calif 94305, USA. rfernald@stanford.edu

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The selective advantages of using light as a source of information are reflected in the diverse types of extant eyes. The physical properties of light restrict how it can be collected and processed, resulting in only eight known optical systems found in animals. Eyes develop through tissue rearrangement and differentiation. Our understanding of the source of genetic information used in developmental programs is growing rapidly and reveals distributions of gene expression with substantial overlap in both time and space. Specific genes and their products are used repeatedly, making causal relationships more difficult to discern. The phenomenon of groups of genes acting together seems to be the rule. Throughout evolution, particular genes have become associated with distinct aspects of eye development, and these suites of genes have been recruited repeatedly as new eyes evolved.

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I realize that neither of these are what you ask for, but the sudden evolution of an eye, or even basic photosensitive cells is not something that happens with sufficient frequency that we've managed to observe it in the lab in the last 50 years we've been examining genetics.But we know mutation creates genes, and that natural selection changes their frequency. We know that eyes are genetic, and we can trace their genetic ancestry through the genomes of various organisms. In this way we can identify the mutation events that led, each time, to eyes of greater functionality; and eventually, even eyes in the first place.

No, there's considerable difference between the species of today and the species represented in the fossil record.But you need to understand that you have a misapprehension about what a transition in the fossil record would look like. Individuals don't transition. Individuals stay the same species they were born as, throughout their life.It is populations that change and evolve, and there's an enormous fossil record of changing populations; a record that agrees with the genetic evidence to such an unlikely degree that the inescapable conclusion at this time is that our reconstructed phylogenies are largely accurate. That record of changing populations is made of fully-formed, static individuals.

Here's an animal called a "tapir":As you can see, it has a very short trunk.

To what degree do you believe soft tissues like eyes fossilize?

In the fossil record? Or now?There's certainly a record of population change in the fossil record. And there's certainly been observation of population change in today's living populations. But they don't become radically different organisms in one generation; it's a slow process of change. Well, we do infer it. We infer it from the observation of the same kind of change occuring today. Darwin didn't propose NS and RM just by looking at fossils; he proposed it by examination of living populations and the effects that selection can have on them. Since his time we've substantialy increased our observations of the change that NS and RM are capable of; we've come to realize that NS and RM are inescapable forces in the natural world, and so, theymust also apply to living things in the past.

All theories are based on inference, from the kinetic theory of gases to the germ theory of disease. That's why our conclusions are tentative. Evolution contradicts neither mathematics nor the Second Law. In fact, the Second Law is what makes evolution possible. When someone wins the lottery, do you grapple with the incredibly small chance that they would have won? Why or why not? It seems to me like you accept improbable events all the time. What's the fundamental difference between humans and single-celled organisms? Aren't they both based on genetics?

No. No, presumably, a population of short-trunk elephants developed increasinly longer trunks over many, many generations. Or, perhaps it happened quickly, when elephant populations were very small. Have you ever seen an elephant fossil trunk? Neither have I. Do you think that might be because soft tissues like trunks don't generally fossilize?

No, that has never happened. Organs don't just spring into being. They don't have to - organs develop evolutionarily over time; the function of tissues is not constant. Changes are additions on a functional level. We do observe the evolution of new functionality, but this takes many generations, so we only have observations in things like bacteria.Function is not constant through time. Evolution often co-opts organs for new purposes.

Woah, ease off on the guns there, chief.What exactly are the odds of what we are talking about here? be sure to show your work. But don't accuse me of disingenuity when you're the one making improbability arguments without actually having calculated any probabilities. You find intelligence to be the fundamental difference between humans and other organisms? Then it's clear you're no student of primatology. Any human behavior you can name, I can find an analogous, if less advanced, behavior among the other primates.But that's neither here nor there. There are no physical differences between humans and anything else that can't be accounted for by genetics. And we have two mechanisms proven to cause significant change in the genetics of populations. There are experiments that prove that these interdependant systems can arise via natural selection and random mutation. In the classic experiment, Lac operons were removed from E. coli; they took out the entire genetic mechanism for the metabolization of lactose. Totally gone. Then they put a colony of these organisms on a lactose substrate and started starving them.Within a certain number of generations, that functionality returned, as "irreducable complex" (which I suppose was the phrase you were looking for) as the last system had been. It arose through duplication and modification of other systems. What odds? Show me your work. Are you taking into account cooption of other functionality?

Exactly. That's where new biological functions come from - cooption of old ones. There's very little biological novelty. That fact is how we're able, in part, to reconstruct phylogeny.But you're moving the goalposts. In fact, your rebuttal - that what changed was an already useful system - disproves your original point; that the precursors to an IC biological system would have no function. In this case, clearly they did.This message has been edited by crashfrog, 09-30-2004 06:23 PM

You tell us. You're the one arguing from probability.Has it occured to you that you don't get an advanced degree in biology without considerable training in statistical analysis? Not to make an argument from authority or anything, but why is it that you think biologists, trained as they are in statistical mathematics, almost universally support the theory, if indeed it is contradicted by probability as you say? I'm just wondering how it is, in your view, that the biological community comes to support a theory you claim is mathematically unbelieveable.

Based on what, though? Your own incredulity? Your refusal to believe that NS + RM has that kind of power, even though it's been demonstrated over and over again?There isn't really that much morphological innovation, anyway. The vast, vast majority of it is slight changes to stuff that was already there. It happens because small genetic change, to small numbers of gene locii, can cause great morphological change.

The first evolutionists were creationists. If evolution is just the result of biased research, how did it get started in the first place? If ideological bias could affect research to that degree, there would never have been any evolution.