Final answer:
Evolution encompasses both ancient and modern processes like natural selection and genetic drift, with the fossil record providing evidence of changes over time. Darwin's theory of evolution by natural selection offers a framework for understanding these changes, supported by evidence across multiple scientific disciplines.
Step-by-step explanation:
Processes, Evidence, and Theories of Evolution
Evolution refers to changes in organisms over time, driven by processes such as natural selection, genetic drift, mutations, and gene flow. Observable evidence supporting evolution includes the fossil record, which shows a progression of life forms from simple to more complex, along with morphological, biochemical, and geological data. The theory of evolution by natural selection, proposed by Charles Darwin, explains how beneficial traits become more common in a population, leading to evolutionary change. Today, evolution is understood as a unifying principle linking diverse biological concepts, with evidence from various disciplines, including mathematics, to support its accuracy.
Modern processes causing evolutionary changes include environmental pressures that lead to adaptation and speciation. Ancient processes can be inferred from fossils that indicate gradual changes and the emergence of new species over geological timescales. Scientific theories, notably Darwin's theory of evolution, propose mechanisms for how these changes occur, primarily through natural selection, where organisms with advantageous traits have greater reproductive success. This theory, continually validated by scientific evidence, illustrates the ongoing evolution of populations.