The Terrans (Humans) (WIP)

History
Most humans are descendants of pioneers, conquerors, traders, travelers, refugees, and other people on the move. As a result, terran worlds are a mix of people - physically, culturally, religiously, and politically. Hardy or fine, light-skinned or dark, showy or austere, primitive or civilized, devout or impious, humans run the gamut.


Physiology
Human body types vary substantially. Although body size is largely determined by genes, it is also significantly influenced by environmental factors such as diet and exercise. The average height of an adult human is about 1.5 to 1.8 m (5 to 6 feet) tall, although this varies significantly from place to place. The average weight for a human is 76–83 kg (168–183 lbs) for males and 54–64 kg (120–140 lbs) for females. Unlike most other primates, humans are capable of fully bipedal locomotion, thus leaving their arms available for manipulating objects using their hands, aided especially by opposable thumbs.

Although humans appear hairless compared to other primates, with notable hair growth occurring chiefly on the top of the head, underarms and pubic area, the average human has more hair follicles on his or her body than the average chimpanzee. The main distinction is that human hairs are shorter, finer, and less heavily pigmented than the average chimpanzee's, thus making them harder to see.

Human skin hues can range from very dark brown to very pale pink, while human hair ranges from blond to brown to red to, most commonly, black, depending on the amount of melanin (an effective sun blocking pigment) in the skin and hair, with hair melanin concentrations in hair fading with increase age, leading to grey or even white hair.

The skin pigmentation of contemporary humans is geographically stratified, and in general correlates with the level of ultraviolet radiation. Human skin also has a capacity to darken in response to exposure to ultraviolet radiation. Humans tend to be physically weaker than other similarly sized primates, with young, conditioned male humans having been shown to be unable to match the strength of female orangutans which are at least three times stronger.

Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short 'flush' canine teeth. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young specimens. Humans are gradually losing their wisdom teeth, with some individuals having them congenitally absent.

The average sleep requirement is between seven and eight hours a day for an adult and nine to ten hours for a child; elderly people usually sleep for six to seven hours.