The Science of Biological Evolution (no politics or religion)

this thread is about evolution - not about the evolution by natural selection from darwin.

'Which happens to be what happens in the real world, and has for the last 3.5 billion years. Indeed since natural selection is virtually a tautology, this is hardly surprising.

presently the science differenciate evolution by natural selection, by sexual selection and gendrift.

The evolution of genetic material over time comprises exactly two components: the deterministic one of natural selection and the random one of mutation. The latter causes an increase in diversity over time, but cannot result in genetic drift of any other kind except by a selective process.

Let me elaborate on that. Suppose random mutation produces variants in genetic information A and B. For A to become more common, it has to be replicated more than B. For A to become the only variant, B has to become extinct. Both of these are clearly examples of natural selection occurring.

The supposed argument about the importance of genetic drift rests solely on the observation that some instances of natural selection are the result of sporadic events which have no importance for long term viability. This is of course the case. To illustrate with a simple example, suppose variant A and variant B led to no intrinsic advantage, but that by chance, all the carries of A got eaten by crocodiles, while all the carriers of B did not. This would be natural selection, but the thing being selected (eg very specific location relative to crocodiles) happens to have no relationship to the genetic information. It is fair to view such things as drift, but its role is clear.

As for sexual selection, fron a gene-centric viewpoint this is merely a characteristic of the environment and doesn't have a special status. The subtlety of it is that sexually reproducing organisms evolve faster (this has a precise information theoretic meaning), so genes that are carried by such organisms have a general advantage. But this is only relevant to the comparison between the evolution of sexually reproducing species and asexually reproducing ones.

And if you are going to bring in this aspect of the fitness of genes, you need to also bring in the aspect of horizontal transfer, especially in microbes, which plays an analogous role (although less efficiently) providing a greater ability to adapt in organisms that use it, which provides a fitness benefit to all genes carried by such organisms over those in organisms that don't take advantage of horizontal transfer.

the idea that species can have a common ancestry and that species are transforming is about 2600 years old.

Interesting, but at the same time, people came up with all sorts of false hypothesis, some of which are still around in fundamentalist circles. Science is about establishing hypotheses as true, abd until that happens, hypotheses are just hypotheses. [Another good example is the atomic hypothesis].

the theory of darwin was in contradictio to the lamarckismus - but had many wide gaps.

then mendel came - with a system of rules for heredity

then the neodarwinismus came up as a combination of mendel and darwin.

then the first DNA was found

and now genetic and molecular biology are the science basic for the modern synthetic theory of evolution.

so - darwins theory was about evolution - but evolution is much more than this old theory

Yes, that is an excellent description. However, because Darwin was a very good scientist, there is very little that he did say that was false, and he said a great deal that remains true. No-one could disagree that a great deal of detailed understanding has been added in the last 140 years, with a detailed understanding of genetics being at the core.

and who says that evolution is not science - and in the same post that evolution = darwin - does not know enough about that theme to discuss it.

True. We see grand proclamations on this subject by people who lack any expertise. Their loudness is no replacement for in depth understanding of the science. Let me be unambiguous: Ghostess is one such person.

we know some theories about atomics - some are very old. of course no of these models are totally right - and of course the first ideas - 2400 years ago - were just theories or thesis - but in the meantime we built atomic bombs lol - and - the same dramatic development happened to the theories of evolution - darwins theorie was only one of about 100 known theories in the 19th century. and i wonder why people still talk about that artefact. shall we talk about the first atom-modells? would be the same.

The evolution of the atomic model would be a good topic for another discussion!

Off the top of my head, Democritus was a bright chap who postulate that atoms might have different shapes and features (such as ball and socket joints). He did not have the slightest idea of what materials different types of atoms might correspond to.

It was not until the time of Avogadro that further progress was made, leading to the idea of molecules of specific chemicals, and eventually to the idea of elements. de Lavoisier got the idea of elements partly right and partly dead wrong. These errors got sorted out by others including Mendeleev.

But even then, with the idea of elements being quite accurate, no-one know what an atom was like. It was only with Rutherford that people found out that atoms were made of a tiny nucleus and electrons which made them behave a bit like balls (although not always spherically symmetric).

And then complete understanding arose with quantum mechanics and the modern understanding of the constituents of atoms.

The only thing that survived from Democritus was the idea there was some list of fundamental materials, and these materials are well thought of as some number of atoms of that material.