Lamarckism
The theory of acquired characteristics put forth by Jean-Baptiste P.A. Lamarck (1744-1829), a French botanist, zoologist and biological philosopher.
According to Lamarck, evolution occurs because organisms can inherit traits acquired by their ancestors. Giraffes can only survive by eating leaves high up on trees so they stretch their necks to reach the leaves and this stretching of the neck is passed on to later generations.
The basic tenet of Lamarckism has been rejected. Darwinism (the theory of the origin of species and the development of higher organisms from lower forms through natural selection, the survival of the fittest, and the evolution of humans from an ancestor common to himself and the apes) has prevailed, together with the principles of transmission genetics.
Lysenkoism was a 20th-century Soviet version of Lamarckism.
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- Lamella
A thin leaf, plate, disk, or wafer, such as in bone tissue.
- Lamin A
Progeria syndrome, Emery-Dreifuss muscular dystrophy type 2, Limb girdle muscular dystrophy type 1B, Charcot-Marie-Tooth disorder type 2B1, The Dunnigan type of familial partial lipodystrophy, Mandibuloacral dysplasia and A familial form of dilated cardiomyopathy.
- Lamin A/C
Emery-Dreifuss muscular dystrophy type 2, familial partial lipodystrophy, limb girdle muscular dystrophy type 1B, dilated cardiomyopathy, familial partial lipodystrophy, Charcot-Marie-Tooth disorder type 2B1, mandibuloacral dysplasia, childhood progeria syndrome (Hutchinson-Gilford syndrome) and a subset of Werner syndrome. These diseases have therefore been referred to as laminopathies.
- Lamina
Plates or layers. For example, the lamina arcus vertebrae are plates of bone within each vertebral body.