an alternative, typically based on faith, creation science, or intelligent design. The scientific community has responded by pointing out that their conversations are frequently misrepresented (e.g. by quote mining) in order to create the impression of a deeper controversy or crisis, and that the creationists' alternatives are generally pseudoscientific. Biology Disputes relating to evolutionary biology are central to the controversy between creationists and the scientific community. The aspects of evolutionary biology disputed include common descent (and particularly human evolution from common ancestors with other members of the great apes), macroevolution, and the existence of transitional fossils. Common descent A group of organisms is said to have common descent if they have a common ancestor. A theory of universal common descent based on evolutionary principles was proposed by Charles Darwin and is now generally accepted by biologists. The most recent common ancestor of all living organisms is believed to have appeared about 3.9 billion years ago. With a few exceptions (e.g. Michael Behe) the vast majority of creationists rejected this theory in favor of the belief that a common design suggests a common designer (God). Many of these same creationists through the beginning of the 21st century also held that modern species were perpetually fixed from creation. However, now a large amount of creationists allow evolution of species, in the face of undeniable evidence for speciation. They contend, however, that it was specific "kinds" or baramin that were created initially, from which all present-day species arose. Thus all bear species may have developed from a common ancestor that was separately created to establish a bear-like baramin, by this type of creationism. This type of creationism often acknowledges the existence of evolutionary processes but denies that they demonstrate common ancestry or that evolutionary processes would have produced the diversity of contemporary life. Evidence of common descent includes evidence from genetics, fossil records, comparative anatomy, geographical distribution of species, comparative physiology and comparative biochemistry. Human evolution Human evolution is the study of the biological evolution of humans as a distinct species from its common ancestors with other animals. Analysis of fossil evidence and genetic distance are two of the means by which scientists understand this evolutionary history. Fossil evidence suggests that humans' earliest hominid ancestors may have split from other primates as early as the late Oligocene, circa 26 to 24 Ma, and that by the early Miocene, the adaptive radiation of many