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Goose bumps are an example of a vestigial human reaction to stress. The formation of goose bumps in humans under stress is a vestigial reflex; a possible function in the distant evolutionary ancestors of humanity was to raise the body's hair, making the ancestor appear larger and scaring off predators.
In humans, the vermiform appendix is sometimes called a vestigial structure as it has lost much of its ancestral digestive function.. Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. [1]
The general characterizing feature of the dental morphology of humans are the lack of facial prognathism, a parabola-shaped mandible and maxilla, and molars that are the same size as the front teeth. Humans also have small crowns in relation to body mass and tend to show a reduction in cusp and root number. [8]
Atavisms have been observed in humans, such as with infants born with vestigial tails (called a "coccygeal process", "coccygeal projection", or "caudal appendage"). [8] Atavism can also be seen in humans who possess large teeth, like those of other primates. [9]
Vestigial teeth in narwhal. [101] Rudimentary digits of Ateles geoffroyi, Colobus guereza, and Perodicticus potto. [102] Vestigial dental primordia in the embryonic tooth pattern in mice. [103] Reduced or absent vomeronasal organ in humans and Old World monkeys. [104] [105] Presence of non-functional sinus hair muscles in humans used in whisker ...
A number of other changes have also characterized the evolution of humans, among them an increased reliance on vision rather than smell (highly reduced olfactory bulb); a longer juvenile developmental period and higher infant dependency; [180] a smaller gut and small, misaligned teeth; faster basal metabolism; [181] loss of body hair; [182] an ...
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In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies among individuals and ...