Natural Selection

• Natural selection is the key mechanism of evolution, as stated by Charles Darwin.
• It is a process where organisms that are better adapted to their environment survive and reproduce more than those less suited to the same conditions.
• The first pillar of natural selection is variation - individuals in a species show differences in their characteristics.
• These variations can be due to changes or mutations in the genes.
• A beneficial mutation makes an individual more adapted to its environment, therefore it may live longer and have more offspring, called survival of the fittest.
• This means these beneficial characteristics are passed onto the next generation, leading to evolution over time.
• Factors that can affect the rate at which natural selection occurs include mutation rate, environmental changes and population size.
• It’s important to know that natural selection can only act on existing variation within a species.
• Natural selection can lead to speciation, where new species are formed.
• There are different types of natural selection which include stabilising selection, directional selection, and disruptive selection, each affecting the frequency of traits differently.
• Remember that natural selection doesn’t strive for ‘perfect’ organisms, instead it philtres for traits that are ‘good enough’ for survival and reproduction.