Which of the following is one of Lamarck's theories?
Answer Details
One of Lamarck's theories is that new species originate through the inheritance of acquired traits.
Lamarck was a French naturalist who developed a theory of evolution before Darwin. He believed that organisms could acquire new traits during their lifetime through the use or disuse of certain parts of their bodies, and that these acquired traits could be passed down to their offspring.
For example, Lamarck believed that if a giraffe stretched its neck to reach higher leaves on a tree, it would develop a longer neck over time. He also believed that if a blacksmith developed large muscles from using his arms and hands, his children would inherit those large muscles.
This theory of the inheritance of acquired traits has since been disproven, as it is now known that traits are determined by genetics and are not acquired during an individual's lifetime. However, Lamarck's ideas were influential in the development of the theory of evolution, and his emphasis on the importance of adaptation and change over time was an important contribution to the field.
The other options given in the question are not theories of Lamarck, but rather concepts in the field of biology. "Some variations are more favourable to existence in a given environment than others" is a concept related to natural selection, which was proposed by Darwin. "All living organisms are constantly involved in a struggle to existence" is a concept related to the idea of survival of the fittest, which was also proposed by Darwin. "The size of a given population remains fairly constant" is a concept related to the principle of population ecology, which is the study of how populations of organisms interact with their environment.