Charles Darwin, one of the first theorists of evolution.
Evolutionary biology is an integral part of biology in general – the study and theory of evolution in organisms. More than just a subfield, one can see this field as the lens through which all of biology must be viewed, creationists notwithstanding. Evolutionary biology is concerned with the origin of species through genetic variation and natural selection, as well as with the shared descent of species from common ancestors.
Evolutionary biologists are interested in the forces that led some dinosaur lineages to evolve into modern birds.
Although the biology informed by Darwinian theory dates back to Darwin’s publication of On the Origin of Species in 1859, modern evolutionary biology did not emerge from the modern evolutionary synthesis until the 1930s and 1940s, and it was not until the 1970s and 1980s that universities began to create departments with the term “evolutionary biology” as part of their titles. The enormous amount of fossil knowledge discovered in the early to mid-20th century made it possible to easily trace the evolution of many organisms over time.
Evolutionary biologists are interested in how prehistoric conditions drove the evolution of modern human behaviors.
A popular topic in evolutionary biology is trying to figure out when certain adaptive features first appeared and how many times they evolved in independent lineages. For example, evolutionary biologists have determined that shells evolved in at least 18 lineages, the eye evolved only once, flight evolved four distinct times (insects, pterosaurs, birds, and bats), gliding evolved on dozens of occasions, one O skeleton evolved independently only once, and camouflage evolved hundreds if not thousands of times. The more structurally complex a given adaptation, the more rarely it evolved independently.
Evolutionary biologists are interested in why the reproductive systems of marsupial mammals such as koalas diverge from those of placental mammals.
Evolutionary biology seeks to trace the ancestry of modern organisms as far back as possible, seeing how they evolved from sometimes less sophisticated progenitors. For example, all modern mammals are believed to have evolved from a smaller group of Mesozoic tetrapods called therapsids. These animals lived throughout the Age of Dinosaurs, 180 million years. If they didn’t, modern mammals wouldn’t exist. A major breakthrough in evolutionary biology came when consensus emerged, supported by fossil evidence, that modern birds evolved from dinosaurs.
Camouflage is considered an evolutionary advantage that helps keep prey out of the sight of predators.
Another task for evolutionary biologists is to solve long-standing evolutionary puzzles, for example the ancestry of modern-day amphibians and turtles. It is currently unclear which group of ancient amphibians gave rise to modern amphibians and whether tortoises derive from more recent reptiles or split off from reptiles soon after the group evolved.