Neo-Darwinism

Neo-Darwinism is the refined version of Darwin’s original theory, incorporating modern discoveries in genetics. It updates, rather than alters, the basic structure of Darwinism.

• The population is recognised as the basic unit of evolution, not the individual or the entire species.
• Evolution is the change in the frequency of an allele within a population due to local environmental conditions.

Physical Basis of Heredity: Genetic differences among individuals are caused by:

• Accumulation of mutations (new alleles).
• Genetic recombination during sexual reproduction (independent assortment, crossing over, and fertilisation).

Inheritance Mechanism: Characters themselves are not directly inherited. Instead, genes ("character determiners") are passed down. The final physical trait (phenotype) results from the interaction between the genes and the environment.

Role of Natural Selection: While Darwin thought natural selection was the main cause of adaptations, Neo-Darwinians view it as just one of multiple evolutionary forces.

• Neo-Darwinism integrates modern genetics with Darwin's original theory, establishing the population - rather than the individual - as the fundamental unit of evolution.
• Evolutionary change is defined as the alteration of allele frequencies within a population in response to local environmental conditions.
• Genetic variation among individuals is primarily driven by the accumulation of mutations and genetic recombination during sexual reproduction.
• Organisms inherit genes, not physical traits; the final observable characteristic (phenotype) results from interactions between these genes and the environment.
• Natural selection is recognised as one of several contributing evolutionary forces, rather than the sole driver of adaptation.