Describe the process of evolution by natural selection as developed by Charles Darwin in the 1800s.

Evolution by natural selection occurs when random mutations in the genome of an organism causes phenotypic traits (observable characteristics or traits) to be different between individuals of an organism. These differences can be beneficial to an organism, for example by improving reproductive success or making the individual better suited to surviving in the environment, leading to the individuals with the positive traits being more likely to survive into adulthood and produce offspring (termed "survival of the fittest").
These mutated genes are passed onto offspring who in turn are more likely to survive and these organisms with adapted traits come to dominate the niche the species inhabits and outcompete individuals without the traits until over generations the majority of the species has adapted and inherited the mutated phenotype.