Overview

After the theory of spontaneous generation was discredited, only religious explanations were offered to explain the origin of life. Alexander Oparin (1894-1980), an atheist, suggested that natural chemical reactions produced biological molecules that came together to form the first living thing. Later, Stanley Miller tested this hypothesis and produced chemical "building blocks" but not life itself. In spite of much progress, there is still no clear consensus on how life originated on Earth. Some scientists are even looking to outer space for the origin of life.

Background

The first scientist to synthesize a molecule normally produced by living organisms was Friedrich Wöhler (1800-1882). In 1828, he accidentally made urea by heating ammonium cyanate. This finding helped dispel a theory known as "vitalism," which taught that living things and their components possessed...