Homo sapiens
human

Humans are currently found throughout the world; in permanent settlements on all continents except Antarctica and on most habitable islands in all of the oceans. All available evidence suggests that humans originated in Africa. (Boaz and Almquist, 2002; Findley et al., 1975)

Anatomically modern Homo sapiens populations are known from the Middle East as long as 100,000 years ago, from east Asia as long as 67,000 years ago, and southern Australia as long as 60,000 years ago. European Homo sapiens fossils are known from 35,000 years ago. Homo sapiens populations were once thought to have colonized the New World approximately 11 to 13,000 years ago, but recent research indicates earlier dates of colonization. This is an area of active research. (Boaz and Almquist, 2002)

Humans are found in all terrestrial habitats worldwide. Humans extensively modify habitats as well, creating areas that are habitable by a much reduced set of other organisms, as in urban and agricultural areas. With the aid of technologies such as boats, humans also venture into many aquatic habitats, primarily to obtain food. (Boaz and Almquist, 2002; Findley et al., 1975)

Humans are an exceptionally diverse species morphologically and many aspects of size vary substantially with environmental factors such as nutritional status. Historically there has been an effort to organize human physical variation into "races," although there is no scientific basis for the application of a race concept to human variation. Human physical variation is continuous and available evidence suggests that gene flow among human populations throughout their history has been the rule rather than the exception. (Boaz and Almquist, 2002)

Humans are characterized by their bipedalism and their lack of significant body hair. Males are generally larger than females, with more pronounced muscle development and generally more hair on the face and torso than females. (Boaz and Almquist, 2002)

Human lifespans vary tremendously with nutritional status and exposure to diseases and trauma. Humans can live more than 100 years; the longest lived human that has been documented was 122 years old. Most humans live 50 to 80 years old, providing they survive their most vulnerable childhood years. Average life expectancy in many parts of the developing world is from less than 40 years old to 65 years old. In the developed world average life expectancy can be over 80 years old. (U.S. Central Intelligence Agency, 2008)

Humans are one of the most behaviorally, socially, and culturally complex animal species. Ancient humans were nomadic hunter gatherers but the development of agriculture approximately 10,000 years ago revolutionized the way that humans live. Agriculture ultimately led to increases in regional human populations and concentration in urban centers, and dramatically altered the cultures, economies, and relationships among human populations. In general, humans are highly social animals that are active mainly during the day. Some human populations remain nomadic or migratory, while most live mainly in one general area. (Boaz and Almquist, 2002; Findley et al., 1975)

One of the most notable aspects of human biology and evolution is the extensive use of tools. Early human populations constructed sets of specialized tools, such as chisels and knife blades, from stones, bone, antler, and ivory. Human technological innovation is one of the most definitive human characteristics. Related to this innovation is the complex development of human art and symbolism, including written languages. (Boaz and Almquist, 2002)

Home Range

Human home ranges vary widely among populations and use of space is extremely flexible.

Like most primates, humans use vision extensively in perception and communication. Humans have excellent color vision, although visual acuity in low light is limited. Humans also use sounds extensively. Human languages represent one of the most complex systems of communication in the animal world, and the diversity of human languages is astounding. Touch is an important mode of perception, it is especially important in close social bonds. Humans have a moderately well developed sense of smell and taste, which is used to determine the suitability of foods and discover information about the environment and conspecifics. (Boaz and Almquist, 2002)

The evolution of complex language is considered one of the hallmarks of Homo sapiens. Archaic humans were capable of complex language, although Homo sapiens anatomy seems to have evolved to favor the production of complex sounds in anatomically modern humans. (Boaz and Almquist, 2002)

Humans generally eat a highly variable omnivorous diet. The components of diets vary tremendously with regional availability of foods. Some human cultures restrict their diet to a vegetarian one, relying on plant sources of proteins. Foods are often extensively prepared and stored for future use. The use of fungal colonies, such as yeasts, for creating cultured foods, such as beer, bread, and cheeses, is widespread. (Boaz and Almquist, 2002)

Humans have few natural predators and often sit at or near the top of the food chain in regional ecosystems. Humans are sometimes opportunistically preyed on by large wild cats, such as tigers (Panthera tigris) and lions (Panthera leo). Other instances of large, carnivorous animals eating humans are often cases of mistaken identity or are opportunistic events. This includes cases involving large sharks, bears, monitor lizards, and crocodiles.

Humans act as top predators in many ecosystems, although they are also sometimes preyed on by larger predators, such as tigers. Humans modify habitats and ecological communities in countless ways, often substantially changing the interactions of nearly all other species in those habitats. (Boaz and Almquist, 2002)

Humans are parasitized by many species of internal and external parasites. Some research suggests that hairlessness in humans is an adaptation to reduce ectoparasite loads. (Boaz and Almquist, 2002)

Humans and human societies have evolved multiple relationships with other species, including commensal species and domesticated and companion species. Human commensals are too numerous to mention, but some important commensal species are house mice (Mus musculus), black rats (Rattus rattus), Norway rats (Rattus norvegicus), and Oriental cockroaches (Blatta orientalis). Important domestic species include domestic dogs (Canis lupus familiaris), pigs (Sus scrofa), cattle (Bos taurus), sheep (Ovis aries), goats (Capra hircus), chickens (Gallus gallus), guinea pigs (Cavia porcellus), horses (Equus caballus), llamas (Lama glama), camels (Camelus species), turkeys (Meleagris gallopavo), honeybees (Apis mellifera), and many other animals. Humans have also domesticated many species of plants for food and other uses, such as corn (Zea mays), rice (Oryza sativa), wheat (Triticum aestivum), manioc (Manihot esculenta), apples (Malus domestica), and soy (Glycine max). (Boaz and Almquist, 2002)

Human interactions are often complex and negative at interpersonal levels and among social groups, cultures, and governments. Human activities often destroy or transform ecosystems, and these changes can have negative economic and/or medical impacts on other human populations. (Boaz and Almquist, 2002)

Human populations are not monitored by conservation agencies. Although human populations worldwide are large and growing, some regional or isolated populations may be in decline as a result of economic disadvantage, disease, habitat degradation, emigration, and cultural erosion.

Earliest Homo sapiens appeared approximately 700,000 years ago, although anatomically modern humans are known from about 100,000 years ago. Patterns of colonization of the world by ancient humans and the details of interactions between ancient Homo sapiens and co-occurring Homo species are areas of active research. (Boaz and Almquist, 2002)