Principles of evolution by natural selection

• Evolution is the change of inherited characteristics within a population over time through natural selection
• Evolution may result in the formation of a new species
• All species of living things have evolved from simple life forms over a period of time
• The Earth is about 4.5 billion years old
• Life on Earth began more than three billion years ago
• Natural selection is the process whereby the best-adapted individuals survive longer, have more offspring and spread their characteristics
• Individuals in a species show a wide range of variation due to differences in their genes
• Individuals with characteristics most suited to their environment are more likely to survive and reproduce
• Genes that allow individuals to be successful within their environment are passed on to their offspring
• Poorly adapted individuals are less likely to survive and reproduce
• Over time, a species will gradually evolve
• Both genes and the environment can cause variation, but only genetic variation can be passed on to the next generation
• If two populations of one species become increasingly different in phenotype that they can no longer interbreed to form fertile offspring, this can result in the formation of two species
• Peacocks provide a simple example of evolution through natural selection, where females choose a mate based on the colourful tail feathers of the males