Q. explain me these terms: 1. Neo-lamarckism 2. Neo-Darwinism 3.Sexual dimorphism
Here is the explaination of these terms..
Neo-Darwinism: It is also called the modern evolutionary synthesis, generally denotes the integration of Charles Darwin's theory of evolution by natural selection, Gregor Mendel's theory of genetics as the basis for biological inheritance, and mathematical population genetics. Although this was not the historical meaning of the term neo-Darwinism, it has been the popular and scientific use of the expression since the synthesis of the 1930s. Other terminology used synonymously with neo-Darwinism are modern synthesis, evolutionary synthesis, and neo-Darwinian synthesis.
Neo-Darwinism has been one of the most significant, overall developments in evolutionary biology since the time of Darwin. Bowler (1988) stated that there is "a sense in which the emergence of the modern synthetic theory can be seen as the first real triumph of Darwinism."
Essentially, neo-Darwinism introduced the connection between two important discoveries: the units of evolution (genes) with the mechanism of evolution (natural selection). By melding classical Darwinism with the rediscovered Mendelian genetics, Darwin's ideas were recast in terms of changes in allele frequencies. Neo-Darwinism thus fused two very different and formerly divided research traditions, the Darwinian naturalists and the experimental geneticists. This fusion took place roughly between 1936 and 1947.
Darwinism in the latter part of the 19th century faced an alternative evolutionary theory known as neo-Lamarckism. This hypothesis shared with Lamarck’s the importance of use and disuse in the development and obliteration of organs, and it added the notion that the environment acts directly on organic structures, which explained their adaptation to the way of life and environment of the organism. Adherents of this theory discarded natural selection as an explanation for adaptation to the environment.
For Neo-Lamarckism, these are the points to be remembered,
1. It is a modification of the original theory of Lamarck in order to make it more suitable to modem knowledge.
2. Neo-Lamarckism does not give any importance to these factors.
3. The theory stresses on the direct effect of changed environment on the organisms.
4. Normally only those modifications are transferred to the next generation which influence germ cells or where somatic cells give rise to germ cells.
Q. Sexual dimorphism
Sexual dimorphism: It is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. The condition occurs in many animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, and may also include behavioral and cognitive differences. These differences may be subtle or exaggerated, and may be subjected to sexual selection. The opposite of dimorphism is monomorphism.
For Sexual dimorphism, in simple you can say...the differences in appearance between males and females of the same species, such as in colour, shape, size, and structure, that are caused by the inheritance of one or the other sexual pattern in the genetic material.
For example, in some species, including many mammals, the male is larger than the female. In others, such as some spiders, the female is larger than the male.