BIOLOGY Volume 3 - A Guide to General Biology - 2004

26. EVOLUTION, OR THE HISTORY OF LIFE ON EARTH

26.6. Modern Conceptions of Evolution

The Theory of evolution proposed by Darwin and Wallace has been expanded and developed in light of modern data from genetics, paleontology, molecular biology, ecology, and ethology (the Study of behavior), coming to be known as neo-Darwinism. Neo-Darwinism can be defined as the theory of organic evolution through the natural Selection of heritable traits.

Different aspects of neo-Darwinism rely on various types of evidence. In order to accept the neo-Darwinian evolutionary theory formulated above, it is necessary to:

1) establish the fact of past evolution (change) in the past (past evolution);

2) identify the mechanism producing evolutionary changes (natural selection of genes);

3) demonstrate evolution occurring at the present time ("evolution in action").

Evidence for evolution that occurred in the past is provided by fossils and stratigraphic data (The Study of the sequence and age of rocks). Data on The Mechanism of evolution are obtained through experimental research and observations concerning the natural selection of heritable traits, such as shell color selection in Cepaea (Section 27.5.1), and the mechanism of inheritance demonstrated by classical genetics, such as Mendel's work on peas. Finally, information on the operation of these processes at present comes from the study of modern Organism populations, such as the investigation of speciation in the herring gull (Section 27.8.4), as well as the results of artificial selection and Introduction/32.html">Genetic Engineering, such as the creation of new wheat varieties and Gene synthesis.

Firmly established laws of evolution do not yet exist; there are only well-supported hypotheses that together form a thoroughly substantiated theory. However, currently widespread ideas should not be accepted as proven facts, as this may stifle The Development of thought and the pursuit of truth. The uncritical acceptance of certain concepts within evolutionary theory serves as an example of this. Some events cited as evidence for evolutionary theory can be reproduced under laboratory conditions, but this does not mean they actually occurred in the past; it merely demonstrates that such events are possible. In modern scientific discussions about evolution, the debate centers not so much on the fact of its existence, but rather on whether it occurs through the natural selection of spontaneously arising Mutations.