10 assertions about evolution

Looks good to me.

I like some of your statements but I'd be inclined to "edit" one or two. How about ....

1. Macroevolution is an essential, misunderstood component of modern evolutionary theory.

3a. Surprisingly, many visible phenotypic changes are not adaptations.

3b. Random genetic drift affects evolution at all levels.

9. Speciation is a crucial and underappreciated step in evolution.

10. Every single modern species, including Homo sapiens, is evolving.

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Given replication with variation and selection, evolution is inevitable.
Four words to spare.

Given a finite population with variation, evolution is inevitable.

Given heritable differences in survival, selection is inevitable.

I came up with my own list before reading yours. It was a little tricky figuring out what you were asking us to do without looking at your list.

What does FCD stand for?

What does FCD stand for?

Friends of Charles Darwin.
sign up today.

I know it sucks, but here my own version.

[1.]Given imperfect replication, change is inevitable.

[2.]Some accidental changes will pick up in frequency as a function of benefit.

[3.]*Man* is still evolving & will continue to; no reason to suspect that the process has stopped because we have become knowledgeable about it.

Note: Imperfect replication is also the way *sexual* reproduction, I think.

I think I'm with you on all but your first assertion. In fact, the jury is out as far as the distinction between micro- and macroevolution is concerned. Just a few observations:

First, while it is clear that, across closely related species, exonic differences are generally minor or effectively neutral in effect (i.e., translated proteins that aren't really terribly different functionally in sibling species or synonymous base changes that yield no differences whatsoever), 5' tracts of untranslated [intronic] DNA containing promoter regions likely do start to differ markedly in more distantly related species. No one has yet come up with a good way to either quantify these changes or determine the threshold of change in cis element number and kind (motif?)that must be exceeded before a dramatic shift in morphology appears.

Nevertheless, it seems that it's less of an evolutionary "house of cards" to tinker with promoter elements than to muck around with tracts of exonic DNA in a given gene, the product of which might be pleiotropic and therefore wide-ranging and perhaps deleterious. In any case, macroevolution--what we could perhaps regard as the appearance of new animal forms higher than the genus level and lower than the phylum level--might often be dictated by the same sort of cis changes at the level of DNA that one might observe across closely related species (microevolution?). But sharing a common mechanism doesn't necessarily reduce the difference between micro- and macroevolution to a matter of semantics.

Confusing as this might seem, a difference in degree and/or kind of 5' DNA modification could, at certain points, have yielded dramatic epigenetic transformations. This is not a particularly new idea; King and Wilson suggested such regulatory shifts as the fodder for macroevolution more than thirty years ago when it became clear that we needed an explanation for the near- [structural] genetic identity of ape and human. And Sean Carroll has lately taken up this theme and added much needed fresh meat to these bones. In any case, I think most evolutionary biologists with a genetics bent would very much argue that micro- and macroevolution, at the level of morphological organization, are two distinctly different things.

Certainly, at levels of organization higher than phyla, there have been profound reorganizations of whole genomes (i.e., many gene and chromosome duplications, fusion events, and the rise of entirely novel gene "circuits") that surely had an impact on animal morphology. This is relatively uncharted territory in terms of firm evolutionary theorizing. But the structural genomic changes are nevertheless an observable fact.

Even though we're still far from understanding how a one-dimensional code--DNA--yields three dimensional forms, it is clear that, at some level of genetic and epigenetic organization, there have been modifications that resulted in discontinuous shifts in morphology and behavior.

Darwin was unaware of either the mechanism for inheritance or the nature of gene regulation (e.g., where changes in degree of DNA "signal"--homeobox gene expression for example--can yield profound changes in phenotype "kind") when he envisioned evolution as a gradual, incremental process. If he had known, I'd like to think he might have followed his pal Lyell's advice and abandoned his dogmatic adherence to gradualism--which may in fact be one of the roots of the controversy regarding micro- versus macroevolution.

I'd add something about "The evolution of life on Earth took six thousand years." *

You know, just to give the Young-Earth Creationists a bit of a loophole.

* Provided you are passing through our part of the universe at 99.999999999913% of the speed of light. Then 4.55 billion years of Earth-time would be time-dilated to just 6000 years in your rest-frame.

RE: evolution
Scientists Find Brain Evolution Gene
http://beepbeepitsme.blogspot.com/2006/08/scientists-find-brain-evoluti…

Whoa, number 6...Definatly mistaken there.. Remember Kimura 1983. Strength of selection=Ne*s. Anyway, here is my list