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Lamarck argued, as part of his theory of heredity, that a blacksmith's sons inherit the strong muscles he acquires from his work. [1]Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, [2] is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime.
The inheritance of acquired characteristics (also called the theory of adaptation or soft inheritance) was rejected by August Weismann in the 1880s [Note 3] when he developed a theory of inheritance in which germ plasm (the sex cells, later redefined as DNA), remained separate and distinct from the soma (the rest of the body); thus, nothing ...
An acquired characteristic is a non-heritable change in a function or structure of a living organism caused after birth by disease, injury, accident, deliberate modification, variation, repeated use, disuse, misuse, or other environmental influence. Acquired traits are synonymous with acquired characteristics.
Jean-Baptiste Lamarck's 1809 evolutionary theory, transmutation of species, was based on a progressive (orthogenetic) drive toward greater complexity. Lamarck also shared the belief, common at the time, that characteristics acquired during an organism's life could be inherited by the next generation, producing adaptation to the environment ...
Evolutionary progress as a tree of life. Ernst Haeckel, 1866 Lamarck's two-factor theory involves 1) a complexifying force that drives animal body plans towards higher levels (orthogenesis) creating a ladder of phyla, and 2) an adaptive force that causes animals with a given body plan to adapt to circumstances (use and disuse, inheritance of acquired characteristics), creating a diversity of ...
In addition, Darwin and others considered Lamarckian inheritance of acquired characteristics entirely possible, and Darwin's 1868 theory of pangenesis, with contributions to the next generation (gemmules) flowing from all parts of the body, actually implied Lamarckism as well as blending. [10] [11] [12] August Weismann's germ plasm theory.
Thus, pangenesis theory allowed for the Lamarckian idea of transmission of characteristics acquired through use and disuse. Accidental gemmule development in incorrect parts of the body could explain deformations and the 'monstrosities' Darwin cited in Variation. [2]
Lysenkoism, as a scientific theory, aimed to replace Darwinian evolution and genetic theory with a new theory, one that can explain and justify the phenomena claimed by Lysenko to exist, such as vernalization, species transformation, inheritance of acquired characteristics, vegetative hybridization, etc.