3. PREVIOUS EVOLUTIONARY THEORIES
In general, science has changed a lot in the past century (20th century) and, yet, regarding the theory of evolution or evolutionary theory it seems strange that it has not changed significantly.
Although there are small updates, the accepted theory of evolution is the Darwinian presented in work The Origin of the Species in 1859. This evolutionary theory consists of what surely all of us have heard about or studied.
According to the evolutionary theory of Darwin, individuals present random variations and evolution comes about by natural selection. These variations are also named as random mutations to point out their supposedly unguided nature.
The Darwinian theory punched the evolutionary theory proposed by Lamarck, where traits acquired during the life of individuals passed on to their descendants. A classic example is the evolution of the giraffes’ neck. According to the evolutionary theory of Lamarck, the first giraffes, by constant stretching of their necks to obtain food, managed to lengthen them and subsequently to breed descendants with necks a little longer. As for Darwin, he maintained that random giraffes born with longer necks were luckier than the average, survived more, and bred more descendants.
Among the theories of evolution, strictly speaking, we find the laws of Mendel (1865) about genetic inheritance, whose fundamental elements are the combination of genes and their dominant or recessive trait. It is worth pointing out that at the end of the 19th century, this theory remained unknown and not because Mendel did not try to publish it as some people say.
In short, the ideas presented by Lamarck, Darwin, and Mendel make up the general body of biological evolution or evolution of the species. Nonetheless, it is also worth pointing out the existence of minor theories derived from the previous ones and others of religious nature.
Regarding the new theory of the Conditional Evolution of Life, nowadays, we know new processes like:
Foam type evolution, i.e., close species communicates through some individuals, so that it does not follow the typical tree structure, which biologists thought in the past. Therefore, it should be challenging to find an inexistent missing link.
There is the inheritance of acquired characteristics.
The answer to new knowledge by orthodox doctrine is an adaptation of Darwin's theory in the long term, as occurred during the twentieth century. Moreover, in the short period, it is to make concepts relative and blatant changing of names and notions to avoid recognizing past mistakes; however, its big mistake was the design of the books of general education of the population.
Now, if there is the inheritance of acquired characteristics is not anymore the evolution propounded by Lamarck, but molecules inherited, although different from DNA molecules.
It seems Darwin was an expert in genetics and epigenetics, and he distinguished between heritable DNA and other molecules. Moreover, alleles are no longer different versions of genes for small chemical variations, but any gene that fulfills a similar function, although the mutation of a gene to its academic allele would be virtually impossible.
Doing some archeology of science to understand what is happening with theories of evolution and the origin of man, we see that orthodox doctrine has not changed the definition of the Royal Spanish Academy -RAE-, which says:
f. Biol. Doctrine where the traits that characterize a living being fix in the course of its development, without being established in the fertilized egg.
Epigenetics ➹ is no longer gene expression by environmental conditions –such as the above RAE definition– but any gene expression, even if it comes from the previous generation genetic information, as far as it does not come from DNA. It seems the intention is to incorporate mutations produced in the life of earlier generations without recognizing that Lamarck was right and, incidentally, acknowledging and explaining that DNA and other molecules transmit genetic information.
Either way, inheritance of modifications of genetic information produced in the life of the previous generations relate to phrases “the organ creates the function” and “the inheritance of acquired characteristics,” and as a modernist expression, we could say epi-inheritance.
We must remind the scientific community that Darwin's theory was never proven; especially now that it is obvious Lamarck's theory is correct.
Nevertheless, as theories of the origin of man both agree because they are evolutionary theories.
Let us go on now to carry out a critical analysis of the most relevant evolutionary theories.
Likewise, a brief description of those evolutionary theories is in the addendum of about the human origin.