1 Charles Darwin of Shrewsbury, England, was a naturalist scientist who laid the foundation for the theory of evolution and the survival of the fittest, which most scientists would hold today. He worked on his theory for 20 years before publishing his book On the Origin of Species by means of natural selection.
2 Erasmus Darwin was a philosophical radical influenced by the French Enlightenment, which gave him ideas about human equality and liberty that also included the liberty to think freely about the existence of God and the natural origins of Earth’s creatures. This would have influenced Charles’s own thinking and intellectual interests.
3 As the latter half of Darwin’s life was spent mainly within his family, Huxley became the public face of evolutionary theory and described himself as Darwin’s bulldog. The most famous example of Huxley’s work was his debate with Bishop Wilberforce during the British Association meeting at the Oxford University Museum on 30 June 1860.
4 As well as reading Lyell’s book Principles of Geology, Darwin made meticulous notes on the species he encountered. These led him to the conclusion that species gradually change to fit into their environment. This view of gradual change led him to believe that the spectacular variety of life found on this planet had been brought about through causal changes.
Species are made up of individuals that change ever so slightly from each other in a wide number of traits.
These species increase in size over generations at an exponential rate.
Predators, disease and limited resources bring about a continual battle for survival within species.
Nature seems to give some members within species slight advantages over others, which allow some, for example, to resist disease better than others or to run faster than their predators.
These members of the species not only survive but are able to take care of their offspring.
Those who survive better, pass on the traits, which make them survivors to their offspring.
This is why Darwin gave the name ‘natural selection’ to the process of passing on these favourable traits.
Over a long period, this natural selection will tend to make the nature of a species change.
It is this process that ultimately brings about new species with different classifications. The processes also weed out changes or mutations that do not strengthen life. This theory not only explains the variety of species but predicts the need for continued changes, both positive and negative, among species.
6 When on this group of islands, Darwin noticed that the finches on the different islands, while being fundamentally similar to each other, showed wide variations in their size, beaks and claws. He saw, for example, that the beaks were different depending on the local food source. As these islands are nearly 1,000 kilometres from the nearest mainland, the finches had arrived there in the past and changed over time to suit the available resources on the different islands.
7 This phrase is really a quick way of referring to the whole process of natural selection. In any given environment, those species that are most suited, or fittest, will be the ones that thrive.