A lot of the “coming together” just happens through sexual reproduction. Also I think a lot of times we tend to have the wrong picture of evolution. We tend to have a mental picture of discrete mutations causing new things like feathers or eyes. But a lot of evolution is not about creating new things, its about taking old things and making very simple changes like increasing/decreasing size, changing number, rearranging things by making some developmental process happen earlier/later, faster/slower. An incredible amount of variation can just be accomplished by using these type of changes which doesn’t necessarily involve the creation of whole new genes but just very small tweaks to already existing genes which cause the genes to express themselves more strongly/weakly, duplicate gene sequences or alter timing.

In fact I would bet that most of our genes probably come from very early ancestors and all evolution has done is tweak this genes very very slightly to lengthen something here, shorten something there, increasing the number of something etc in order to create us.

This isn’t really that different that human technologies. For instance the latest Intel microprocessor is basically the same technology as the 8086. All intel has done is reduce size, lower voltages, enlarge buses, duplicate various functional blocks. There are some genuinely new ideas but a lot of the design is just small variations on old ideas.

This is not to say the physicist’s skillset couldn’t and doesn’t contribute enormously to many problems in biology and biochemistry. Protein folding, the fundamentals of enzymology, the inner workings of molecular motors and ion channels, ever more realistic models of nucleotide interactions, the means to organize and efficiently access the staggering amount of sequence data now available, many basic aspects of electrophysiology, new and better imaging technologies, the list goes on and on. Actually, folks like me have been utterly dependent on folks with the physics skillset just to do the experments we already do (I sure as Hell couldn’t design a flow cytometer, and would probably find even constructing a simple inverted microscope a career-busting challenge). Envious sometimes? Maybe. Defensive about it? Not really. Deeply grateful is more like it. There’s plenty of work to go around, and division of labor according to facility has always worked before. I do my job, and it makes me happy. What more could I really ask for?

When I said graded into each other, I meant more the speciated demarcations at a given time rather than change over time (i.e., why isn’t life more messily graded from one type to another at any given time, like color shades.)

Have you heard of ring species?

People who study individual organisms recognize that there are gradients within populations of a single “species”; these are sometimes called “subspecies” and sometimes just “populations.” And careful study also shows that what to the casual eye might seem a single species turns out to be two or more closely related species — see the discussion of scrub jays, for example.

Once two species become unable to breed with each other (”reproductively isolated”), they will tend to drift apart. New mutations will appear in one species, but be unable to spread to the other, because the two groups of organisms are no longer one big breeding population.

Yes, I have heard of the changing of whole genes etc, which to me is part of the higher-lever anthropic fine-tuning of atoms and chemistry principles. Well, does that explain the “longitudinal evolution” of DNA that I asked about?

Sure, if by “longitudinal evolution” you meant DNA growing (or shrinking) in length. Go read the Wikipedia “Mutations” article, and you’ll see that some of the mutations end up duplicating stretches of DNA (or deleting stretches).

PS – I suspect that because biology is “softer” than physics, that ironically makes practitioners defensive in reaction. Are they then less willing to admit that things in their field are unsettled, the way that astronomers freely admit that dark matter and dark energy are weird and ill understood?

My impression is that biologists are happy to admit that things on the cutting edge are weird and ill understood (e.g., What’s going on with “junk DNA” — is it really all non-functional? How did the first eukaryotic cells arise and become differentiated from bacteria? Are there limits to how fast or slow evolution can work in practice? etc.). But just as astronomers don’t feel there’s anything “unsettled” about whether the Earth goes around the Sun or vice-versa, or whether there really was a Big Bang of some sort, biologists don’t feel there’s anything unsettled about the basic fact of evolution.

You’re misunderstanding how evolution works. All it takes is one beneficial mutation in one creature. If the mutation really is beneficial, then that creature will tend to have more offspring than its fellows, and those offspring will have more offspring of their own than their contemporaries, etc., until — hundreds or thousands of generations later, probably — the last organisms without that mutation die out and all living members of that species are descendants of that initial mutant. At which point, it’s a generic feature of that species. (How fast this happens — how fast the mutant version of the gene “spreads” through the population — depends on how beneficial it is. If it just gives you a slight advantage, then it’s a slow process; if it helps you survive a widespread disease or poison, then it will spread faster.)

So it’s more like: some dinosaur had a mutation that made its scales slightly featherlike and better at keeping it warm, so it could survive cold weather better, lived longer, and had more offspring. Eventually, its descendants ended up dominating the population. At some point, there was another mutation which happened to make the scales slightly better insulators (a little longer? a little more feathery?), and eventually its descendants dominated the population. And so on, for millions of years.

(And of course there were bad mutations, which made things worse, but their carriers tended to die out.)

I believe the mathematical basics of this process were worked out in the first few decades of the 20th Century, as part of what’s called “population genetics.” And it’s been observed, in detail, in experimental studies of bacterial evolution. (As well as things like the spread of pesticide or antibiotic resistant in historical times, of course.)

No, I have a very strong opinion… that isn’t distorted by unscientific prejudice.

“Gotcha”

The extremely sad fact of the matter is that people, in general, are ideolgically warped, and they do not change.”

Except for you, I suppose I’m meant to understand. No “matter of opinion” there, of course. Gotcha.

I don’t know about Sean, but no, it is absolutely no use whatsoever, except to validate this fact, as well as the ideologically motivated delusions of either side of the debate. Course, that’s not what you wanted to hear, and it’s easy to deny that science isn’t being forsaken by both sides of the debate, but I constantly prove otherwise.

The extremely sad fact of the matter is that people, in general, are ideolgically warped, and they do not change.

If there is one truth in this universe that requires both sides to set aside their ideological belief systems in order to recognize, then it might as well not even exist!

You can write that in stone.

Like ole’ Sam Clemens wisely noted…

The rule is perfect. Both sides know that in matters of opinion, (like the interpretation of evidence), the other is insane.

He was as correct about that as a person can be.

Okay, I return you’s to fantaslyland…

I have my faults, like the hubris it may require to disagree with one of your intellect on occasion, but I deepy appreciate the hard work you put into science outreach, and the generally outstanding quality of the information you disseminate. My carreer is as a bio. researcher (just gave a talk in Seattle this month…I love it), and it’s really quite gratifying to see physicists show an interest in the field, as well as to see them taking the time to defend it from magical thinking.

But, reading some of the comments above, I have to wonder if it’s any use. The refractory nature of some minds never ceases to astonish, and discourage, no matter how many times I encounter the phenomenon. Oh well. Thanks for trying, anyway.