Charles Darwin, an English naturalist who lived from 1809 to1882, developed the theory of evolution by natural selection, the current unifying theory of the life sciences, which explains explains the origins of diverse life forms and how they became adapted to their particular environments

Darwin's Early Life

Darwin was born in Shrewsbury, England, in 1809. Darwin attended Christ's College in Cambridge in 1827, where he became an avid amateur naturalist, and graduated in 1831.

The HMS Beagle

After graduation, Darwin joined the HMS Beagle as a naturalist for a five-year round-the-world journey of surveying and exploration. Darwin meticulously recorded his observations and collected numerous specimens from South America, the Galapagos Islands, and elsewhere.

Fossils

Darwin unearthed many fossil creatures when he was in South America, which began his speculation about how new species originated.

The Galapagos Islands

In the years following the voyage of the Beagle, Darwin examined his own notes, sketches, and specimens. Darwin discovered that many of the specimens were from unique species, found nowhere except the Galapagos. This led him to speculate about how species could come to those islands and then change their forms in isolation.

The Origin of the Species

After 20 years of research, Darwin finally published the "Origin of the Species" in 1859, which explains his theory that species evolve through a process tha the contemporary English biologist Herbert Spencer called "the survival of the fittest."

Source:

The Complete Works of Charles Darwin Online

Truman State University: Herbert Spencer