Human Variation in Anthropology

The process by which organisms with traits better suited to their environment tend to survive and reproduce more successfully, passing on their advantageous traits to their offspring.

A type of natural selection where one extreme phenotype (trait) is favored, leading to a shift in the population's average trait over time.

A type of natural selection where the average phenotype is favored, reducing variation in the population.

A type of natural selection where multiple phenotypes are maintained within a population, preventing fixation of a single trait.

Traits that do not significantly affect an organism's survival or reproductive success in an environment, and therefore are not subject to strong natural selection.

The process by which organisms adjust to their environment over time. This can happen within an individual's lifetime (acclimatization) or over generations (adaptation).

Changes in the physical environment, like climate, altitude, and diet, can influence human growth and development.

Cultural practices, like cooking and clothing, can influence human growth and development by modifying our physical needs and selection pressures.

A rule stating that individuals in colder climates tend to have larger body sizes, reducing surface area to volume ratio for better heat retention.

A rule stating that individuals in colder climates tend to have shorter limbs, further reducing surface area for heat loss.

The amount of melanin, a dark pigment, in the skin plays a significant role in determining skin color.

Facial features, like a prominent nose, are often associated with colder climates, potentially aiding in warming and humidifying inhaled air.

Skin color is a complex trait influenced by multiple factors, including ancestry, genetic variation, and exposure to sunlight.

A condition of oxygen deficiency that often occurs at high altitudes.

The tendency for individuals from populations with a long history of living in a particular environment to be better adapted to that environment compared to individuals from populations with less time in that environment. This can involve both genetic and cultural factors.

The idea that the genetic homogeneity of a population increases its vulnerability to disease outbreaks. This is because there is less genetic variation in the population, so a disease is more likely to be able to infect a large proportion of individuals.

The situation where a disease is introduced to a population that has no prior exposure to it, leading to a rapid and widespread outbreak.

A genetic disorder that affects red blood cells and can have a protective effect against malaria in certain environments.

The occurrence of a trait (like sickle cell anemia) within a population even though it can be harmful, because it also provides a survival advantage in certain environments (like malaria-prone areas).

The idea that humans are biologically divided into distinct and separate races is a misconception, as there is more genetic variation within groups than between them.

Race is a social construct, meaning it's a concept created by humans to categorize and understand differences. These categories are based on perceived physical characteristics, often linked to social and cultural meanings, but don't reflect underlying biology.

Skin color is determined by the amount of melanin, a pigment, produced by our body. Genetic factors inherited from our parents, and exposure to sunlight, determine melanin production.

Gloger's Rule states that darker pigmentation in animal populations is more common in warmer climates. This is understood as an adaptation to protect against the damaging effects of ultraviolet (UV) radiation from the sun.

Dark skin offers protection from UV radiation, reducing the risk of skin cancer and folate deficiency. This is thought to be an advantage in sunny climates.

Light skin, while less protective against UV radiation, allows for better Vitamin D absorption in areas with less sunlight. This is crucial in temperate climates where vitamin D deficiency can be a problem.

A condition characterized by a reduced amount of oxygen in the blood, often caused by high altitude or other environmental factors. Individuals living in high altitudes tend to have larger lungs, a higher density of red blood cells, and other adaptations to compensate for hypoxia.

Cultural factors can indeed contribute to differences in height, such as through diet and access to healthcare. These factors can influence growth and development, but cultural factors alone do not explain all height variations. Genetics, environment, and overall health play important roles.