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The human brain. Differences in male and female brain size are relative to body size. [83] Early research into the differences between male and female brains showed that male brains are, on average, larger than female brains. This research was frequently cited to support the assertion that women are less intelligent than men.
However, such sex differences are primarily limited to the anthropoid primates; most of the strepsirrhine primates (lemurs and lorises) and tarsiers are monomorphic. [2] Sexual dimorphism can manifest itself in many different forms. In male and female primates there are obvious physical difference such as body size or canine size.
In the absence of a Y chromosome, the fetus will undergo female development. This is because of the presence of the sex-determining region of the Y chromosome, also known as the SRY gene. [5] Thus, male mammals typically have an X and a Y chromosome (XY), while female mammals typically have two X chromosomes (XX).
Sexual differentiation is the process of development of the sex differences between males and females from an undifferentiated zygote. [1] [2] Sex determination is often distinct from sex differentiation; sex determination is the designation for the development stage towards either male or female, while sex differentiation is the pathway towards the development of the phenotype.
The human skeleton is not as sexually dimorphic as that of many other primate species, but subtle differences between sexes in the morphology of the skull, dentition, long bones, and pelvis exist. In general, female skeletal elements tend to be smaller and less robust than corresponding male elements within a given population.
Sex differences in human physiology are distinctions of physiological characteristics associated with either male or female humans. These can be of several types, including direct and indirect, direct being the direct result of differences prescribed by the Y-chromosome (due to the SRY gene ), and indirect being characteristics influenced ...
In terms of brain size differences, it has been noted that given the larger skull in neoteny humans, brain volume may be larger than an average human brain. It has been hypothesized that this is one mode of which the brains of Homo sapiens grew as a species, as the prolonged development of neurons may have led to hypermorphosis, or excessive ...
Skull in situ Human head skull from side Anatomy of a flat bone – the periosteum of the neurocranium is known as the pericranium Human skull from the front Side bones of skull. The human skull is the bone structure that forms the head in the human skeleton. It supports the structures of the face and forms a cavity for the brain. Like the ...