Particulate inheritance

[1] Early in the 19th century, scientists had already recognized that Earth has been inhabited by living creatures for a very long time.

Blending inheritance was the common ideal at the time, but was later discredited by the experiments of Gregor Mendel.

When a pea plant produces gametes (reproductive cells), it segregates one allele to each one.

[3] In a 1918 publication titled "The Supposition of Mendelian Inheritance Among Close Relatives," R.A. Fisher showed that particulate inheritance was capable of generating the vast amount of variation we see among closely related individuals.

This helped to reconcile the Biometric and Mendelian schools of thought at the time, and was an important step in the modern synthesis.