Final answer:
Evolution is the biological process that describes the gradual change and differentiation of species over time and is driven primarily by natural selection, alongside other factors like mutation that introduce genetic variation.
Step-by-step explanation:
The process that refers to the gradual change and differentiation in species over time is known as evolution. This concept is a fundamental aspect of biology that explains how life on Earth has changed and diversified from common ancestors. Natural selection is a major mechanism of evolution, where individuals with beneficial traits tend to produce more offspring, leading to the propagation of these advantageous characteristics throughout the population. Other processes such as mutation introduce genetic variation, which is a necessary component for natural selection to act upon. Over time, these evolutionary processes can lead to the adaptation of organisms to their environment and the emergence of new species.
Evolutionary theory is supported by a wide array of scientific disciplines, including mathematics, which helps to model and understand patterns in evolutionary biology. The process of evolution is not random because natural selection favors traits that improve survival and reproduction, leading to populations that are better adapted to their environments.