Albinism in humans all vertebrates, including humans. It is due to absence or defect of tyrosinase, a copper-containing enzyme involved in the production of melanin. It is the opposite of melanism. Unlike humans, other animals have multiple pigments and for these, albinism is considered to be a hereditary condition characterised by the absence of melanin in particular, in the eyes, skin, hair, scales, feathers or cuticle. While an organism with complete absence of melanin is called an albino, an organism with only a diminished amount of melanin is described as leucistic or albinoid. The term is from the Latin "albus", "white". There are
Muscular evolution in humans defender and hunter. An increase in running as a hunting and survival activity was perhaps fundamental to this development While there is no proof that modern humans have become physically weaker than past generations of humans, inferences from such things as bone robusticity and long bone cortical thickness can be made as a representation of physical strength. Taking such factors into account, there has been a rapid decrease in overall robusticity in those populations that take to sedentism. For instance, bone shaft thickness since the 17th and 18th centuries have decreased in the United States, indicating a less physically stressful