His work on classifying worms, spiders, molluscs, and other boneless creatures was far ahead of his time. Lamarck was struck by the similarities of many of the animals he studied, and was impressed too by the burgeoning fossil record. It led him to argue that life was not fixed. When environments changed, organisms had to change their behavior to survive. If they began to use an organ more than they had in the past, it would increase in its lifetime.
Its offspring would inherit the longer neck, and continued stretching would make it longer still over several generations. Meanwhile organs that organisms stopped using would shrink. This sort of evolution, for which Lamarck is most famous today, was only one of two mechanisms he proposed.
As organisms adapted to their surroundings, nature also drove them inexorably upward from simple forms to increasingly complex ones. Like Buffon, Lamarck believed that life had begun through spontaneous generation. Consider a year period that starts and ends with normal years but has a one-year famine, two two-year famines and a three-year famine in between. Which of the three groups normal, small, Epi2s will be most successful?
Are there famine patterns in which Epi2s overwhelm the other two groups over the very long term? As these vignettes show, it does not matter to natural selection whether characteristics are controlled by genetic or epigenetic mechanisms.
If the conditions that confer a fitness advantage on a given group last long enough and select that group across multiple generations, then that group will dominate the population, and the species characteristics will change. So if there is a sizable subset of a population that exhibits advantageous epigenetic inheritance, natural selection is very likely to maintain it.
On the other hand, if epigenetic modifications in a population are deleterious, natural selection will eliminate it. There is no top-down, purposeful information passing across generations here, no matter how sensible that seems to us.
Based on these considerations, can you speculate how the elegant information transfer across generations that is embodied by the CRISPR-Cas system in bacteria could have evolved? So deep and so inexorable is the blind, bottom-up process of natural selection in evolution that there is no way to contain its potency, and no rival mechanism for creating adaptation. Natural selection and its analogs in non-biological spheres may well be the major — or only — processes that create complex novelty at all levels of the universe.
And that includes the complex novelty created by us. Note that we may hold comments for the first day or two to allow for independent contributions by readers. Update: The solution has been published here. Topics Covered: The Age of Darwin. Jean Baptiste Lamarck:. Although the name "Lamarck" is now associated with a discredited view of evolution, the French biologist's notion that organisms inherit the traits acquired during their parents' lifetime had common sense on its side.
Web Activities. About the Project. Site Map. For example, simple organisms are still detected in all varieties of life, plus it is now known that mutations can create variation such as neck length.
The work of Lamarck Charles Darwin is recognised as the scientist most associated with the theory of evolution, however, a number of other scientists were influential in this field.
Lamarck's theory At the beginning of the 19th century Jean-Baptiste Lamarck was a French scientist who developed an alternative theory of evolution before Charles Darwin.
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