Dictionary » L » Lamarckism




The theory suggesting that traits or characteristics of an organism are produced and inherited by direct influence of the physical environment, by effort, or by use or disuse of body parts.


According to this theory, individuals lose characteristics they do not require (or use) and develop characteristics that are useful. These characteristics or traits are caused by changes or mutations in the organism that are directed towards some objective so the organism would become better adapted to a particular situation or to its environment, and the traits acquired or learned during its lifetime can be passed on to its offspring which would also be possessing these traits.

However, this theory is no longer widely accepted like before. For instance, according to this theory, the giraffes evolve into having long necks because of their stretching to reach for the leaves on tall trees, and this trait had been passed on to its offspring. But other leaf-eating animals with short necks would not need a long neck to survive. A sheep does not need longer neck as it can eat leaves from grass. This indicates the giraffe's neck is long not because of the result of direct mutation, nor because it is a requisite for survival, but because it is caused by random mutation.

Word origin: named after the French biologist Jean-Baptiste Lamarck.
Synonym: Lamarckian theory.
See also: direct mutation, soft inheritance.

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Neo-Orthogenesis and Neo-Darwinian evolution

... pantheistic philosophy. I completely reject the classical non-Darwinian, unilinear, orthogenetic hypothesis that is often associated with Lamarckism and which has been convincingly discredited with-the almost universal acceptance of-Darwinian natural selection. However I have come to adopt ...

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by valetudo
Tue Mar 11, 2014 11:12 am
Forum: Evolution
Topic: Neo-Orthogenesis and Neo-Darwinian evolution
Replies: 0
Views: 3613

Re: modern synthesis

... neo-larmakianism is misguided. IAC, e.g. epigenetic changes, Yes it was discarded and ignored by the modern synthesis, but theres no evidence neo-Lamarckism is wrong. Recent papers conclude that certain mechanisms for evolution fit the criteria to be described as "Lamarckian". saltatationism ...

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by Forests
Sat Oct 06, 2012 4:01 pm
Forum: Evolution
Topic: modern synthesis
Replies: 2
Views: 3368

Re: Evolution of complex structures

... Genetic drift, gene flow, horizontal gene transfer, molecular drive, saltation, symbiosis, niche construction, evo-devo, epigenetics (also see neo-Lamarckism) hybridization, self-organization etc... theres even a mechanism called "internal selection" theres also controversial stuff like ...

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by Forests
Thu Jul 19, 2012 6:14 pm
Forum: Evolution
Topic: Evolution of complex structures
Replies: 4
Views: 5661

Re: Natural selection ends in absurdity or nonsense

... for alternatives to replace natural selection they call this perioud the eclipse of Darwinism. So which alternative theories are there? Theres neo-Lamarckism the notion that aquired traits can be inherited, saltation (evolution by jumps via large mutations etc), theistic evolution, vitalism or ...

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by Forests
Thu Jul 19, 2012 5:42 pm
Forum: Evolution
Topic: Natural selection ends in absurdity or nonsense
Replies: 26
Views: 28650


I think it would be only referring to Lamarckism if the question asked whether those traits could then be passed on to his/her children. :) I understood the question, whether would it become thiner over generations... It would make more sense ...

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by JackBean
Tue Feb 07, 2012 6:29 pm
Forum: Genetics
Topic: Alternation Of Gene
Replies: 4
Views: 2270
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