macroevolução

Macroevolution refers to evolutionary change at or above the level of species. It encompasses the broad patterns of evolution over long periods, such as the origin of new groups of organisms like mammals or flowering plants, and the extinction of others, like dinosaurs. Macroevolutionary phenomena are typically observed in the fossil record and through comparative studies of living organisms.

Key concepts within macroevolution include speciation, which is the process by which new species arise, and extinction, the disappearance of species. Macroevolution is often contrasted with microevolution, which describes the changes in allele frequencies within a population over shorter time scales. While microevolutionary processes are the building blocks of evolution, macroevolution describes the large-scale consequences of these processes operating over vast stretches of geological time.

The study of macroevolution often involves analyzing patterns of biodiversity, the diversification of life, and the historical biogeography of different lineages. It seeks to explain the grand sweep of life's history and the relationships among major groups of organisms. Evidence for macroevolution comes from various sources, including fossils, comparative anatomy, embryology, and molecular genetics. The fossil record provides direct evidence of extinct species and transitional forms, illustrating evolutionary lineages and major shifts in form and function. Comparative studies reveal homologous structures and genetic similarities that point to common ancestry among diverse life forms.