Evolution is driven by four primary mechanisms that alter the genetic makeup of populations:
: The movement of genes between different populations through migration and interbreeding. Scale and Patterns
Scientists distinguish between two scales of evolutionary change: Evolutionary mechanisms part 1: What is evolution?
Evolution is the gradual process of biological change in a population's inherited traits across successive generations. It is often described as "descent with modification," where all life on Earth is linked by a shared ancestry that has diversified over billions of years. Core Mechanisms of Evolution
: Organisms with traits better suited to their environment are more likely to survive and reproduce, passing those advantageous genes to their offspring.
: Random chance events (like a natural disaster) can abruptly change which traits are passed down by removing certain individuals from the population.
: Random changes in genetic material create new variations. While many mutations are neutral or harmful, some provide benefits that natural selection can then act upon.