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It is also a portmanteau term that describes all biological aspects of the human body, typically using the human body as a type organism for Mammalia, and in that context it is the basis for many undergraduate University degrees and modules. [4] [5] Most aspects of human biology are identical or very similar to general mammalian biology.
Human parents often display familial love for their children. For humans, sexuality involves biological, erotic, physical, emotional, social, or spiritual feelings and behaviors. [332] [333] Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. [333]
The human body is the entire structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organs and then organ systems . The external human body consists of a head , hair , neck , torso (which includes the thorax and abdomen ), genitals , arms , hands , legs , and feet .
A fetus is a stage in the human development considered to begin nine weeks after fertilization. [4] [5] In biological terms, however, prenatal development is a continuum, with many defining features distinguishing an embryo from a fetus. A fetus is also characterized by the presence of all the major body organs, though they will not yet be ...
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
The name Homo of the biological genus to which humans belong is Latin for 'human'. [e] It was chosen originally by Carl Linnaeus in his classification system. [f] The English word human is from the Latin humanus, the adjectival form of homo. The Latin homo derives from the Indo-European root * dhghem, or 'earth'. [220]
The sequence of human evolution from Australopithecus (four million years ago) to Homo sapiens (modern humans) was marked by a steady increase in brain size. [ 264 ] [ 265 ] As brain size increased, this altered the size and shape of the skull, [ 266 ] from about 600 cm 3 in Homo habilis to an average of about 1520 cm 3 in Homo neanderthalensis ...
The human body consists of biological systems, that consist of organs, that consist of tissues, that consist of cells and connective tissue. The history of anatomy has been characterized, over a long period of time, by a continually developing understanding of the functions of organs and structures in the body.