1 Natural Selection *Natural Selection – the process by which organisms that are best suited to a particular environment survive and reproduce most successfully *Variation – differences that exist naturally among members of a population or species Species – a group of organisms having common characteristics *Adaptation – a trait that helps an organism survive in a particular environment Trait – a distinguishing characteristic or quality *Mutation – a change in the genetic material of an organism Genetic Diversity – all the different genetic characteristics in a specific species *Phenotype – the appearance of an organism *Genotype – the genetic make-up of an organism *Niche – the role of an organism in a community Isolation – complete separation from others *Classification/Taxonomy – the assignment of organisms to groups within a system of categories distinguished by structure and origin *Speciation – the formation of a new species usually because of geographic location