This document discusses various ways in which human populations vary and adapt both physically and culturally to different environmental conditions. It covers topics like acclimation, adaptation, albinism, physical variations between populations, Allen's rule, Bergmann's rule, founder effect, genetic drift, impacts of high altitude and agriculture, lactose tolerance, natural selection, responses to heat and cold, skin color variations, vitamin D production, and diseases like smallpox and syphilis. The document is a compilation of definitions and explanations of these biological and anthropological concepts by Obaje Godwin Sunday from the Anatomy Department of Alex Ekwueme Federal University.

1. HUMAN VARIATION
OBAJE GODWIN SUNDAY
ANATOMY, ALEX EKWUEME FEDERAL UNIVERSITY
NDUFU ALIKE, EBONYI STATE
+2348068638121, OBAJE199@GMAIL.COM

2. ACCLIMATION
 To altitude, cold, heat, and UV radiation
The way that a person or organism adapts to
a new environment.
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3. ACCLIMATIZATION
 To altitude, cold, heat and UV radiation
A form of phenotypic plasticity that enables
an individual organism to accommodate to a
complex of environmental factors.
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4. ADAPTATION
 To altitude, cold, heat, and UV radiation
A structure, function, or behavior of an
organism that helps it survive and
reproduce.
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5. ALBINISM
A characteristic of many mammals, including
humans, in which a genetic mutation results
in the inability to produce melanin pigment,
thus resulting in individuals with very light
skin and hair color.
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6. PHYSICAL VARIATION IN HUMAN
POPULATIONS
Noticeable physical variations are: body
build, facial features, skin colour, and height
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7. ALLEN'S RULE
The idea that, within a warm-blooded
species that is spread over a large
geographic area, populations in colder
climates tend to have shorter limbs, hence
having a lower surface-area-to-volume ratio.
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10. BERGMANN'S RULE
The idea that, within a warm-blooded
species that is spread over a large
geographic area, populations in colder
climates tend to have larger body size.
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11. FOUNDER EFFECT
A change in allele frequencies in a newly
established population, relative to an
ancestral population, due to the chance o
which individuals were part of the founding
ancestors of the new population.
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13. GENETIC DRIFT
Changes in allele frequencies seen in natural
populations from generation to generation
in circumstances for which selective,
mutational, and gene flow effects are
otherwise accounted.
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15. HIGH ALTITUDE AND GROWTH
Altitude has an effect on the growth of
height and weight during late childhood and
a more dramatic effect on adolescent
growth.
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18. LACTOSE TOLERANCE
A mutation in the human genome allowed
many adults to digest lactose and drink milk.
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20. LEWIS HUNTING PHENOMENON
A process of alternating vasoconstriction
(narrowing of the blood vessels resulting
from contraction of the muscular wall of the
vessels) and vasodilation (widening of blood
vessels) in extremities exposed to cold.
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21. HYPOXIA
Low oxygen pressure/saturation levels at
high altitude
Lower air pressure at high altitude makes it
feel like there is a lower percentage of
oxygen; normal saturation at sea level is
about 98%.
A condition of low oxygen availability.
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22. NATURAL SELECTION
The process by which adaptive traits
predominate in biological populations due
to a differential reproductive rate; natural
selection forms the basis for evolutionary
change.
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24. CULTURAL ADAPTATION
The process and time it takes a person to
integrate into a new culture and feel
comfortable within it.
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Heat and cold, dairying and
milk digestion

25. NEGATIVE IMPACTS OF AGRICULTURE
Land conversion, habitat loss, wasteful water
consumption, soil erosion, and degradation.
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26. SMALLPOX
An acute contagious viral disease, with fever
and pustules usually leaving permanent
scars. It was effectively eradicated through
vaccination by 1979.
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27. SYPHILIS
Disease caused by intimate contact that is
caused by the Treponema spirochete; the
disease is present in venereal (sexually
transmitted) and non-venereal forms.
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28. UV RADIATION AND SKIN COLOR
Variations in human skin color are adaptive
traits that correlate closely with geography and
the sun's ultraviolet (UV) radiation.
Melanin, the skin's brown pigment, is a natural
sunscreen that protects tropical peoples from
the many harmful effects of ultraviolet (UV)
rays.
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WHY EUROPEANS ARE SO WHITE-SKINED
CREAM USED TO FIGHT POLLUTION AND UV RAYS
UV MATERIALS

30. VITAMIN D, CALCIUM & UV RADIATION
Vitamin D is a hormone that controls
calcium levels in the blood. It is needed to
develop and maintain healthy bones,
muscles and teeth and is also important for
general health.
Vitamin D is made through a series of
biochemical processes that start when the
skin is exposed to the sun's UV rays.
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31. GENETIC DRIFT CONTINUED ……..
Refer to various random processes that
affect gene frequencies in small but isolated
populations.
Its also called Wright effect
Founder principle occurs here, where a small
group recently derived from a larger
population migrates to a relatively isolated
location.
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32. SKIN COLOUR
Wide range of skin colour among people of
the world
Skin colour of a person depends on:
1. Amount of melanin pigment (dark)
2. Amount of blood that flows to skin surface
3. Gloger’s Rule
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Warm climate have more melanin, and more darker people