Evolution is the change in the heritable characteristics of biological populations over successive generations. Driven by mechanisms like natural selection, genetic drift, and mutation, it generates biodiversity and explains how organisms adapt to their environments.Heritability: Traits are coded for by genes and passed from parents to offspring.Genetic Variation: Within any population, individuals possess different combinations of traits due to random genetic mutations and sexual reproduction.Natural Selection: Organisms with traits better suited to their environment are more likely to survive, reproduce, and pass those advantageous traits on to the next generation. Over time, this causes the population to change.The Fossil Record: Reveals a chronological history of life, showing transitional forms and the emergence of complex organisms from simpler ancient ancestors.Comparative Anatomy: Different species often share similar physical structures (like the bone structure in human, whale, and bat limbs), pointing to a shared common ancestor.Genetics and Molecular Biology: All living things share the same fundamental machinery (DNA/RNA). The degree of genetic similarity between species directly correlates with how closely related they are on the evolutionary tree.Mutations: Permanent changes in an organism's DNA sequence that introduce entirely new traits.Genetic Drift: Random fluctuations in the frequencies of traits within a population, usually due to chance events (such as a natural disaster) rather than environmental adaptation.Gene Flow: The transfer of genetic material from one population to another, often via migration.
