|MadSci Network: Evolution|
A great question that needs some careful consideration to fully treat it with the repect and complexity that it requires. Here is a taste of the issues. This is really a history question, and to look at how science itself evolves and changes as new data become available. Darwin: based his ideas on field observations. We must also remember however that although Darwin gets all the credit Alfred Russell Wallace had the same natural selection idea. This link has some interesting material from the original Darwin, Lyell, Wallace, Malthus work. http://www.inform.umd.edu/EdRes/Colleges/LFSC/life_sciences/.plant_biology/ darwin/darwindex.html All this work was done without knowledge of DNA remember. This is the 1870's. What is most surprising is that at about the same time (give or take 10-15 years) Mendel was showing that something was passed from parent to offspring. But no one took notice of Mendel's work for another 40 years. Today: We have taken Darwin's and Wallace's ideas and combined them with Mendel's work and the recent Genomic work of the modern era of molecular biology to create the what is termed Molecular Evolution. Darwin knew that "fit" was the secret but not how a parents ability to survive by "fitting" and surviving to reproduction led to the child also "fitting". Mendel knew parents gave information to their children. Today we now know all living entities contain DNA, DNA encodes proteins and ultimately all that is the organism (genotype), this genotype is acted on by the environement to give us an interpretation of what the genes code (phenotype), and so it is your genes that are the "fitness". If your genes "fit" well to your lifestyle and environment (niche) you survive and your genes survive because you reproduce. It is interesting philosophically if we disregard the spirit as scientically not proven, what survives death ? Well 1 thing, our genes. If we view life in this way, genes are the real life form and we are just vehicles for them to propagate and evolve. Try reading a relatively old book. "The Selfish Gene" by Richard Dawkins. We are survival machines--robot vehicles blindly programmed to preserve the selfish molecules known as genes. This is a truth which still fills me with astonishment. Though I have known it for years, I never seem to get fully used to it. -- Richard Dawkins. It is available at any good bookstore. I hope this taste has answered your complex question to the degree you wanted and also made you think about the ideas of Richard Dawkins.
Try the links in the MadSci Library for more information on Evolution.