‘Nothing in biology makes sense except in the light of evolution’! So said Theodore Dobzhansky.
Lamarck’s theory of evolution was based around how organisms change during their lifetime, and then pass these changes onto their offspring.
Darwin’s theory, known as natural selection, believed that organisms possessed variation , and these variations led to some being more likely to survive and reproduce than others. Features that made an organism more likely to survive or reproduce are therefore more likely to appear to each generation. Both Darwinian and Lamarckian modalities of evolution appear to be important, and reflect different aspects of the interaction between populations/cells and the environment.(It is look like THE BOHR-EINSTEIN DEBATES about Uncertainty Principle )
Is adaptive mutation or genome reorganisation concepts combine these theories?
Hi, Marpha,
I would like to comment you to things about what yo have said:
1. First of all, science doesn't mind if a theory is "pacific" or "cruel", logic and evidences it is the unique things that matter to enunciate a theory (the human correct behaviour is another thing and it is ethics that is responsible of it).
2. This expression, "fight for survival", is uncorrect: what Darwin really said was "struggle for life" or "struggle for existence", and furthermore he wasn´t the first using it. It have been used by many people along the History. Concretely, Darwin based his ideas on it principally on that he had read on the works of recent authors like Malthus (about population growth) or Charles Lyell (concretely, his Principles of Geology), who quoted turn to Augustin Pyramus de Candolle.
To be true, Darwin was not the first to talk about evolution. By the time Darwin debuted as a scientist, many other naturalists had already challenged the idea that life was fixed since its creation. Lamarck was one of those realizing the existence of changes throughout the fossil record, and thus can be told to be one of the pioneers of evolutionism.
Lamarck's ideas were discredited long ago, because the mechanism he proposed for heredity (inheritance of acquired characteristics) proved false. Although he wasn't able to explain the molecular mechanisms for heredity, his theories (variability created by random mutations and sexual reproduction + natural selection) explained better observed patterns.
Still, it's also true that, in recent times, awareness about the importance of epigenetics is increasing. Epigenetics refers to the stable changes in DNA, supposedly heritable, at least partially, in response to environmental conditions and without any change in the sequence of nucleotids (=no mutations).
So, not saying that Lamarck talked about epigenetic mechanisms, maybe we should revise our strongly deterministic view of evolution due solely to mutations in the DNA sequence, and consider that part of the variation passed on to the descendance may be due to epigenetic changes acquired during the life-time of the parents (=acquired characteres).
Note, however, that the hereditability of epigenetic changes remains controversial.
Hi Mesut, at that time, as Albert and Maria noted, Darwin, Lamarck and A. Russel Wallace etc. had no idea about genes and Mendel's work.
They just knew that species chance with time and the environment they live in.
As genetics progressed as a science it became obvious that inherited genes and gene mutations are the drivers of evolution. Mutations in the germ cells and not the somatic cells are responsible for passing traits from one generation to the next.
In this case, Lamarck premise was wrong, but the jury is still out whether epigenic changes can effect germ cells.
As for the Einstein-Bohr debate. Bohr's notion was that quantum mechanics is based on statistics.
Einstein hated that idea and said "God does not play dice".
Bohr's response was "Albert, stop telling God what He can or can't do".
In the end Bohr was right.
Dear friends
While there may not be as yet many examples fitting Lamarck's theories perfectly, there is now enough evidence to concede that Lamarckian concepts have some merit. Darwinian evolution and Lamarckian theory (which Darwin accepted) to co-exist peacefully. Perhaps in 2059, we will be celebrating 250 years of Darwin and Lamarck.
Dear collègues,
Yes, Lamarck's ideas were discréditer, but it is more pasific theory as the darwinian "fight for survival' ...
The periods changes ..... and now we can see the First theory of évolution (J.B.L.) "in pure juive'.
Félicitations for you attention & question.
Best regards,
MTT
Hi, Marpha,
I would like to comment you to things about what yo have said:
1. First of all, science doesn't mind if a theory is "pacific" or "cruel", logic and evidences it is the unique things that matter to enunciate a theory (the human correct behaviour is another thing and it is ethics that is responsible of it).
2. This expression, "fight for survival", is uncorrect: what Darwin really said was "struggle for life" or "struggle for existence", and furthermore he wasn´t the first using it. It have been used by many people along the History. Concretely, Darwin based his ideas on it principally on that he had read on the works of recent authors like Malthus (about population growth) or Charles Lyell (concretely, his Principles of Geology), who quoted turn to Augustin Pyramus de Candolle.
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