The theory of evolution and natural selection, first introduced by Charles Darwin in the 19th century, explains how the diversity of life on Earth arose and developed over time. Although there are some who disagree with the facts that support it, the theory remains one of the most fundamental concepts in modern biology and stands as one of the greatest scientific discoveries ever made. Understanding how evolution and natural selection work can help you be better informed about today’s most pressing environmental issues, as well as understand that there are no conflicts between science and religion when both are properly understood.

Quick Overview

Life on Earth has changed drastically over millions of years. This is because life adapts to its environment. If a species doesn’t have a way to adapt, then it will die out. This process is called natural selection. Eventually, changes in species’ populations over time result in evolution, which causes new species to appear as old ones disappear. To understand natural selection and evolution better, it helps to think about how these processes explain what we see all around us today.

Key Terminology

​Evolution - a change in the inherited characteristics of a population over successive generations. ​Natural selection - process that favors those individuals best adapted to their environment over time.​ For example, giraffes were faced with two options – develop longer necks or become extinct. In adapting to food resources available, they developed longer necks and a population boom occurred (source). This is an example of natural selection as giraffes with longer necks were more successful at obtaining food.

What Does it Mean To be Natural?

When most people hear natural they think non-artificial, unprocessed, or even just good. In science however, there's an entire school of thought dedicated to what it means to be natural. Essentially, scientists are asking themselves whether anything can be completely natural. If a tree has been exposed to toxic waste, is it still natural? What about a metal that forms naturally under water? Can we ever classify anything as 100% natural?

A Critique of Dawkins Weasel Sentence

As a post-Darwinian era biologist, I must confess to having some problems with Richard Dawkins’s most famous sentence in his book The Selfish Gene. Here it is: We are survival machines - robot vehicles blindly programmed to preserve...our selfish genes. After all, if we can be so callous as to refer to our own cells as selfish, then there is no real rationale for not referring in similar terms to other beings whose DNA we share, such as our fellow members of larger species (and even higher taxonomic orders). In fact, on what grounds would we stop short of referring to interspecies competition between different subpopulations and species as gene wars? But that's another story.

Conclusions on Darwinism, Neo-Darwinism, and Non-Darwinian Evolutionary Theories

In order to fully understand Darwinism, Neo-Darwinism, and other non-Darwinian evolutionary theories, it is crucial that an understanding of both natural selection and random mutation exists first. Both are important aspects in explaining how new species form, spread, adapt to their environment and develop over time. While both can be observed at work without studying more complex theories (such as synthetic theory), they are not always easy to see directly in action. However, they also do not seem as difficult when explained with a model or example. This paper will use two examples - artificial selection and mutations - along with general information about how each works separately in order to explain how Darwinism functions on a greater scale.