by Paul Morley

Created on: July 31, 2009   Last Updated: August 18, 2009

How often have you heard the term "survival of the fittest" used as an explanation for the theory of evolution? In fact, the term fitness in this context has little to do with physical strength or endurance as one might imagine, and use of the term in this context can be misleading.

In fact the term 'survival of the fittest' wasn't coined by Charles Darwin. Rather, it was a phrase used by Herbert Spencer, an English philosopher who first used the term in his own book 'Principles of Biology," although he did so after reading Darwin's "On the Origin of Species."

It is a little ironic that Darwin himself began to use the term "survival of the fittest" in place of the original term "natural selection" in later editions of "On the Origin of Species." This has led to some confusion over the process of evolution as Darwin originally intended it to be understood. It is useful to think of fitness in the context of fit for purpose or usefulness.

This article intends to describe the main points of the theory of natural selection and aims to explain what is meant by the term "survival of the fittest" in this context.

Following extensive travel and study of plants and animals he discovered on his five-year journey around the world from 1831-1836 aboard the Royal Navy survey ship Beagle, Darwin became convinced that all life had a simpler and less-diverse origin than the complexity and diversity seen on his travels. In other words, he had the idea that all life must have come form a common ancestor.

Darwin's natural selection theory is based on the following assumptions. Collectively, these can be though of as survival of the fittest.

Variation of Species

Any population has a natural variation of traits within the species. In other words, individuals within species have characteristics in either physical appearance or behaviour that is slightly different to other members of the same species. Occasionally, these slight differences can offer some sort of advantage to individuals within a species. For example, a colony of birds may have slightly different beak lengths, some longer than others.

Competition for Resources

Within any given environment, there is a limited availability of resources whether that is food, habitat or anything else that species need to survive. As a result of this, not all members of the species will be able to survive to adulthood or be strong enough to successfully reproduce. Using the example of the birds and beak length, those with longer beaks have

• 1
• 2
• Next Page >>