Evolution by natural selection
It is often referred to as simply "the theory of evolution" or just "evolution", although this is actually a conflation of two different concepts:
- evolution refers to the idea that the nature of a species can change (or "evolve") over time – a fact which can be directly observed over human timescales, especially in lower life-forms such as bacteria.
- natural selection refers to the idea that competition for scarce resources inevitably leads to a contest in which those who are more "fit", i.e. those individuals whose particular characteristics make them more likely to win the "competition" for those resources, are more likely to survive and pass any heritable component of that "fitness" on to their descendants.
These two processes in combination lead to a typically very slow but nonetheless almost inescapable gradual improvement of the "fitness" of any particular species.
The main controversies surrounding this theory relate to whether this gradual improvement is sufficient to account for:
- the creation of life from inanimate matter (an idea never proposed by Darwin but largely accepted as the best likely explanation)
- the evolution of complex life-forms, especially animals, from one-celled organisms
- the evolution of humans from animals (specifically primates)
- Darwinism is the philosophical position which holds that evolution by natural selection is scientifically "true" – i.e. that it is in fact the explanation of species origins which best fits all the available evidence. (In other words: "evolution by natural selection" is the theory – which exists whether true or not – and "Darwinism" is the claim that the theory is true.)
- Evolution by natural selection is a scientifically-based theory of species origin.
- Conservapedia: Theory of Evolution
- presents the theory as largely discredited and rejected by the scientific establishment