Bill

Darwin's Dangerous Idea was "descent with modification in the presence of natural selection." That idea has stood the test of time, and it remains the proper statement of "Darwin's Theory of Evolution."

It is a fact that Darwin was wrong in some of the major details discussed in his book, On The Origin of Species. Darwin believed that there would be a blending of the characteristics during mating. As lpetrich correctly points out, Mendellian genetics provided a better (more correct) statement of just how characteristics are inherited from parents to children. The so-called modern synthesis of evolutionary theories combines Darwin's and Mendel's two theories into one grand theory. That theory was the basis for all of biology from the early 1940s (clearly predating the discovery of DNA).

I can't say what was written between 1940 and 1960 about genetic transmission, but I would be really surprised if the discovery of DNA were not substantially anticipated in the literature.

== Bill

lpetrich

I suggest taking a closer look at the history of genetics. Through most of the first half of the 20th cy., the favorite candidate for genetic material was proteins -- such molecules were big, complicated, and variable.

DNA, OTOH, was thought to be some sort of structural element, and a common view was that it came in tetranucleotide pieces.

That changed with Oswald Avery's 1944 experiments on what in a Pneumococcus bacterium turns it from an R (rough skin; relatively harmless) strain to a S (smooth skin; disease-causing) strain. There was something in S bacteria that could turn R bacteria into S ones. But what? Avery decided to experiment by destroying various cell constituents.

Was it the proteins? No.
Was it the membrane lipids? No.
Was it the RNA? No.
Was it the DNA? Yes.

Likewise, in 1952, Hershey and Chase discovered that bacterial viruses insert ~80% of their DNA into their new victims, while leaving ~80% of their protein outside.

Watson and Crick announced their <a href="http://www.nature.com/genomics/human/watson-crick/" target="_blank">discovery of DNA's double-helix structure</a> with a coy comment that

What is significant about this comment is what it does not mention -- any previous speculations on what structures might be necessary for a system to carry heredity. So there are several possibilities:

• W and C were the first to propose such a structure.
• Some others had previously speculated about such structures, but W and C were unaware of these speculations (much like what had happened to Mendelian genetics).
• W and C were aware of some such speculations, but had thought them too vague and generalized to be worth mentioning.
• W and C had shamelessly plagiarized the idea of molecules serving as templates for copies of themselves.

{Rufus: fixed quote}

[ June 08, 2002: Message edited by: lpetrich ]

[ June 08, 2002: Message edited by: RufusAtticus ]</p>

RufusAtticus

Mendelian genetics isn't consistant with evolution via natural selection, it is required for it. In his book R.A. Fisher showed why the digital nature of Mendelian genetics was necessary for natural selection to occur. This happened way before the nature of DNA was solved. Population biologists studying evolution had already worked out many of the properties of heredity. When Watson and Crick solved the sturcture of DNA, it became apparent why heredity had such properties.

~~RvFvS~~

RufusAtticus

The reason for this comment is simple. Watson and Crick's paper was about the structure of DNA not its replication. However, they realized immediatly how DNA replication worked and included that small sentance so another person wouldn't come along and "scoop" them.

~~RvFvS~~

Lizard

Originally posted by randman:

Randman,
You evidently don't understand what the term "scientific predictions" means. It doesn't mean predictions in the sense of crystal-ball reading, predicting the future. It means saying, "If our hypothesis about X is true, then we would expect physical evidence in the form of Y." It's called testing a hypothesis. Of which creationism and ID have no such thing. The entire content of creationism and ID consists of wrong-headed arguments against evolutionary theory. Tell me a testable hypothesis of either one and prove me wrong.

Evolutionary theory *has* been right all along, in its basic assumption, common descent. Darwin was correct about natural selection, his major contribution to our knowledge of how the diversity of life developed. He didn't know anything about genetics, but he suspected some mechanism for transferring adaptations from one generation to the next existed. Are you saying that because he didn't know everything in 1859, evolutionary theory is wrong?

I admit I'm baffled: What, exactly, *are* you saying?

Koiyotnik

I thought that the highest scientific title an idea can receive is that of a "Law".
Am I incorrect? <img src="confused.gif" border="0">

beausoleil

Speaking purely for my own usage as a research scientist, I would say a 'law' in one sense is something systematised from a series of observations - e.g. Bode's law, Ohm's law, Boyle's law.. A theory is some underlying idea or set of ideas that can account for the law and, ideally, predicts or accounts for other observations or laws (second sense - a predicted relationship between observations). For instance, kinetic theory accounts for Boyle's law whereas no theory accounts for Bodes law. A fact would be an observation of some sort.

Speaking again purely as a research scientist, Nucleosynthesis (I'm picking something uncontroversial I hope) might be described as a fact in the popular sense that atoms of most elements were born in stars. But the details of the theory are still being worked on. Evolution seems to me to be in an analogous state.