For all his brilliance and hard work, Darwin didn't know something that all of you know.
The biological basis of inheritance: genetics!
He published the Origin of Species in 1859.
Gregor Mendel published the results of his famous experiments with peas a few years later in 1866.
If Darwin had simply read Mendel's paper, he would have solved one of the most important questions of his day: how traits are passed on from generation to generation!
If he had known this information he would have been able to strengthen his arguments in Origin of Species.
Unknown sources
1900: The Breakthrough Year
Mendel's paper was not noticed or appreciated during his lifetime.
Like the artist Van Gogh, he died without ever being recognized for his brilliance.
In 1900, 34 years after it was published, Mendel's paper was acknowledged by three different researchers.
After this, during the years from 1900–1930, the science of genetics took off!
During these first 30 years the basic principles of genetics were established—particularly as they applied to populations of organisms.
As a result, the field of population genetics emerged.
Hardy and Weinberg did theoretical work linking evolution with genetics through mathematical modeling of populations.
A New Paradigm Emerges
The Modern Synthesis: Neo-Darwinism
By the 1940s, nearly 80 years after both Darwin and Mendel had published their works, Darwin's theory of evolution by means of natural selection was linked with Mendel's theory of genetics as the biological basis for inheritance.
The result was a much more robust understanding of evolution by means of natural selection.
This new paradigm is called the modern synthesis or neo-Darwinism, and is the current paradigm in biology.
One of the architects of the modern synthesis expressed the confidence that biologists had as a result of this paradigm shift:
“Nothing in biology makes sense except in the light of evolution.” — Theodosius Dobzhansky
Evolution's New Definition
Evolution is given a new definition as a result of the modern synthesis's linkage with population genetics.
Evolution is claimed to not act on individuals but to act on populations of organisms by altering their allele frequencies.
In fact, a succinct definition of evolution is simply “a change in allele frequencies of a population.”
This new definition of evolution led to some new language…
A Nuancing of Evolution
Macroevolution: a change from one species into another species
The origin of species.
Example: one original finch from South America evolves to become thirteen different species of finches (which cannot interbreed) in the Galápagos Islands.
Microevolution: a change within species
Origin of breeds, varieties, etc.
Example: one original dog evolves to become hundreds of different breeds of dogs. They are all still the same species and can theoretically interbreed with one another.
Microevolution vs. Macroevolution: the current understanding, for those that accept the modern synthesis, is that microevolution, given enough time (thanks to James Hutton!), will lead to macroevolution—the origin of new species.
