Evolution and Natural Selection

Evolution

Evolution is the process of gradual change that occurs in a species over many generations.
It is brought about by variations in the genetic material within a population.
Evolution explains how all living organisms, including humans, have evolved (changed) from simple life forms that first developed more than three billion years ago.

Natural Selection

Natural Selection is a key mechanism of evolution and was proposed by Charles Darwin.
It is often referred to as ‘survival of the fittest’, where the ‘fittest’ are those that are best suited to their environment, not necessarily the strongest.
It involves variation, overproduction, competition and survival of the best adapted.

Process of Natural Selection

Individuals in a species show a wide range of variation because of differences in their genes.
These variants may occur due to mutations in the DNA sequence.
Individuals with traits that make them advantaged to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation.
Over time, the traits that provide an advantage become more common in the population. This is the process of natural selection.

Evidence of Evolution

Fossil evidence indicates that life on Earth has changed over time and supports the theory of evolution.
Comparative anatomy such as homologous structures (similar structure, different function) and analogous structures (different structure, similar function) provide evidence for evolution.
Modern genetics has provided further supporting evidence through analysis of DNA sequences.

This closes the key points on Evolution and Natural Selection. Ensure you understand how natural selection works and how it drives evolution. Evidence supporting the theory of evolution is key to a comprehensive understanding of this topic.