Final answer:
Evolution is the change in characteristics of living things over time through natural selection, where advantageous traits become more common across generations. This process leads to biodiversity and is supported by various forms of evidence, such as the fossil record and genetic studies. Mutations introduce variability, which natural selection acts upon over long periods, resulting in the evolution of species.
Step-by-step explanation:
The Process of Evolution
Evolution is the change in the characteristics of living things over time, and it occurs through a process known as natural selection. Natural selection is a mechanism of evolution where organisms with traits that provide an advantage in their environment are more likely to survive and reproduce. This leads to those advantageous traits being more common in the next generation. Over many generations, these changes can result in the remarkable variety of life forms that we see on Earth today. It is important to recognize that evolution acts on the phenotype, or the observable traits of an organism, which are influenced by the genotype, or genetic makeup. This process also accounts for the biodiversity we observe within and among species.
Evidence of evolution is found in the fossil record, comparative anatomy, genetic sequences, and observational studies of natural selection in action. Adaptations, traits that aid survival and reproduction, become more prevalent in populations over time as environments change. The theory of evolution by natural selection is one of the cornerstones of modern biology and provides an explanatory framework for the diversification of life on Earth.
Mutations also play a role in evolution by introducing genetic variance. Some mutations can lead to beneficial traits that are then selected for, while detrimental mutations may lead to those traits being selected against. The cumulative effect of these incremental changes over vast spans of time is the diversity of life forms present on our planet today.