Armando Corripio’s letter of Jan. 8 clearly demonstrates the ignorance and misconceptions so many people in Louisiana have about the facts and theories of evolutionary biology.

For example, Corripio writes, “The theory of evolution has some holes in explaining, among other things, how the universe and life came into existence.” Truth be told, evolution says absolutely nothing about the origin of the universe and the origin of organic life on planet Earth. Evolution simply explains the origin of life’s diversity; its multiple forms and unique morphologies. It explains why there are 400,000 species of beetles, why ostriches lost their ability to fly, why frogs lay their eggs in water, while sea turtles lay their eggs on land, and why mammals are the only organisms to nourish their young with milk produced within the mother’s body.

We need to look no farther than the well-accepted and easy-to-explain topic of gravity to help differentiate between a scientific fact and a scientific theory:

Gravity is fact. Objects attract one another. An apple dropped from the roof of a two-story building will fall until it hits the Earth.

Gravity is also theory. There are reasons why the dropped apple falls to the Earth and not to the moon or to the sun. The theory of gravity explains the “how and why” of the fact of gravity.

Evolution is fact. Organisms change over time — Darwin called it “descent with modification.” Evolution is also theory. There are reasons why and how organisms change and adapt and new species evolve.

Thoughts on evolutionary theory began with the early Greek philosophers 300 years before the birth of Christ. Since that time, at least four theories have been proposed, studied and researched, with the first three being discredited and supplanted by the most-recent one, that being Charles Darwin’s theory of natural selection.

Natural selection is the theory which explains some of the “how and whys” of the fact of evolution.

Michael Hiller


Baton Rouge