Modern synthesis (20th century)

Modern_Synthesis

Darwin's_Pangenesis

Blending_Inheritance

Weismann's_Germ_Plasm

William_Bateson

Karl_Pearson,_1912

fitness-landscape-cartoon

Modern synthesis (20th century)

The Modern synthesis is a term used to describe the fusion of Mendelian genetics with Darwinian evolution that resulted in a unified theory of evolution. This synthesis occurred during the early to mid-20th century and integrated ideas from various biological disciplines, including genetics, systematics, paleontology, and ecology.

Historical Background[edit | edit source]

The Modern synthesis emerged as a response to the rediscovery of Mendel's work on inheritance in the early 20th century. Initially, there was a conflict between Mendelian genetics and Darwinian evolution, as Mendel's work suggested discrete inheritance, while Darwin's theory of natural selection implied continuous variation. The synthesis reconciled these views by demonstrating that discrete genetic changes could lead to continuous evolutionary changes over time.

Key Contributors[edit | edit source]

Several key figures contributed to the development of the Modern synthesis, including:

Ronald Fisher, who developed the field of population genetics and demonstrated how Mendelian genetics could be consistent with natural selection.
J.B.S. Haldane, who applied mathematical models to evolutionary biology.
Sewall Wright, who introduced the concept of genetic drift and the adaptive landscape.
Theodosius Dobzhansky, whose work in genetics and evolutionary biology helped bridge the gap between laboratory research and natural populations.
Ernst Mayr, who contributed to the understanding of species and speciation.
George Gaylord Simpson, who integrated paleontology with evolutionary biology.
G. Ledyard Stebbins, who extended the synthesis to include plant evolution.

Core Principles[edit | edit source]

The Modern synthesis is based on several core principles:

Evolution is a gradual process resulting from small genetic changes.
Natural selection is the primary mechanism of evolutionary change.
Genetic variation arises through mutation and recombination.
Populations evolve, not individuals.
Speciation occurs through the gradual accumulation of genetic differences.

Impact and Legacy[edit | edit source]

The Modern synthesis has had a profound impact on the field of biology, providing a comprehensive framework for understanding evolutionary processes. It has influenced various subfields, including molecular biology, developmental biology, and evolutionary developmental biology (evo-devo).