What are the salient features of neo-darwinism? Distinguish it with Darwinism.

Darwinism:
Darwinism refers to the evolutionary theory proposed by Charles Darwin in the mid-19th century, primarily outlined in his seminal work "On the Origin of Species" (1859). The key features of classical Darwinism include:

1. Natural Selection: Darwin proposed that species evolve over time through a process he termed "natural selection." This mechanism involves the differential survival and reproduction of organisms with advantageous traits that enhance their adaptation to the environment.

2. Descent with Modification: Darwin suggested that all life forms share a common ancestry and have descended with modifications from a common ancestral population. This concept challenges the notion of fixity of species.

3. Gradualism: Darwin's original theory implied a gradual and continuous process of evolutionary change occurring over extended periods. Small, incremental modifications would accumulate over time, leading to the development of new species.

4. Variation: Variation within populations is a crucial component of Darwinian evolution. Individuals within a population exhibit diverse traits, and the frequency of these traits can change over generations based on natural selection.

Neo-Darwinism:
Neo-Darwinism, also known as the modern synthesis, emerged in the mid-20th century as a synthesis of Darwinian evolution and Mendelian genetics. It incorporates the principles of classical Darwinism with the understanding of genetic mechanisms. Salient features of neo-Darwinism include:

1. Genetic Basis of Variation: Neo-Darwinism emphasizes the role of genetic mutations as the source of heritable variation within populations. Mutations, changes in DNA sequences, can create new genetic diversity that serves as the raw material for evolution.

2. Population Genetics: Neo-Darwinism incorporates population genetics to explain how gene frequencies change over time within populations. The synthesis with Mendelian genetics allowed for a more precise understanding of how traits are inherited and how they evolve.

3. Mutation and Selection: While natural selection remains a central component, neo-Darwinism emphasizes the role of genetic mutations in providing the raw material for selection. Beneficial mutations can be favored by natural selection, leading to evolutionary change.

4. Speciation: Neo-Darwinism provides insights into the mechanisms of speciation, explaining how new species arise. This can occur through the gradual accumulation of genetic changes or more rapidly through processes like genetic isolation.

Distinguishing Neo-Darwinism from Darwinism:

1. Genetic Basis: The major distinction lies in the understanding of the genetic basis of variation. Neo-Darwinism incorporates genetic mechanisms, especially mutations, as a source of heritable variation, whereas Darwin lacked knowledge of genetics.

2. Population Genetics: Neo-Darwinism integrates population genetics, providing a mathematical and statistical framework to understand the inheritance of traits and their evolution within populations.

3. Pace of Evolution: Neo-Darwinism allows for a more flexible interpretation of the pace of evolution. While classical Darwinism implied gradualism, neo-Darwinism recognizes that evolutionary changes can occur rapidly under certain conditions.

4. Mechanistic Understanding: Neo-Darwinism provides a more mechanistic understanding of how traits are inherited and how they evolve, incorporating the principles of both Darwinian natural selection and Mendelian genetics.

In summary, neo-Darwinism builds upon and refines the foundational ideas of Darwinism, incorporating advancements in genetics and population biology to offer a more comprehensive and detailed framework for understanding the mechanisms of evolution.