In terms of evolution, what is a 'mutation'?

A mutation is defined as a random change in an organism’s DNA that can lead to new traits. This process can occur due to various factors, such as environmental influences or errors during DNA replication. Mutations can introduce new genetic variations into a population, which are essential for evolution as they provide the raw material for natural selection to act upon. When a mutation results in a beneficial trait, it can improve an organism's chances of survival and reproduction, potentially leading to that trait being passed on to future generations.

The other concepts, such as gradual change in species over long periods, are more representative of broader evolutionary processes like speciation and adaptation rather than the specific mechanism of mutation. Additionally, the idea of pre-determined changes does not align with the random nature of mutations, and intentional alterations by humans refer to genetic modifications rather than natural mutations. Thus, recognizing that mutations are random changes in DNA is fundamental to understanding the role they play in evolutionary biology.