ANTHRO ch.5 inquizitive

Although early scientists attempted to classify people into races based strictly on static ____________ categories, we now know that human _____________ variation is too gradual and dynamic to be categorized.

-Phenotypic feedback: Early scientists collected information on phenotypic variation, or variation in the way different populations from widely separated geographic areas look on the outside. They failed to observe the more gradual changes that occur across geographic space, and only paid attention to a small number of the most obvious variables. This is why they thought that different human populations belonged to different races. -Genotypic feedback: We now know that we can only determine whether or not human populations are significantly different from one another by looking at the genotypic variation that exists between them. If there were enough of a difference between different human populations, we could consider those populations to be different races. This has not been observed in our species.

Match the life history stage to its description.

-The postnatal stage: The stage beginning with birth and involving substantial increases in height, weight, and brain growth and development until the reproductive years begin. feedback: The postnatal stage is where the most drastic phases of human growth occur. It includes the neonatal period (about the first month), infancy (the second month to the end of lactation, usually by the end of the third year), childhood (ages 3-7, generally postweaning), the juvenile period (ages 7-10 for girls and 7-12 for boys), puberty (days or weeks), and adolescence (5-10 years after puberty). -The adult stage: The stage of life involving the reproductive years and senescence. Feedback: The adult stage includes the reproductive period, which can last from about age 20 to the end of the childbearing years, usually by age 50 for women and later for men. It ends with senescence, the period of time after the childbearing years. -The prenatal stage: The stage beginning with the zygote in utero, terminating with birth, and involving multiple mitotic events and the differentiation of the body into the appropriate segments and regions. feedback: The prenatal stage includes development during the three trimesters (9 months) that a fetus spends inside its mother's womb during pregnancy. This period ends with birth.

Bergmann's and Allen's rules differ. Bergmann's rule pertains to ____________ whereas Allen's rule pertains to ______________.

-body breadth and size feedback: Bergmann's rule, developed by German biologist Carl Bergmann, states that heat-adapted and cold-adapted animals have different body sizes and breadths, resulting in different volume-to-surface ratios. A shorter and stockier body offers better thermoregulation in colder climates, whereas a taller and narrower body dissipates heat better for hot climates. -limb length feedback: Allen's rule, developed by American zoologist Joel Allen, states that heat-adapted and cold-adapted animals have different relative-sized limbs (arms and legs) or appendages. Narrow and thin appendages such as arms and legs—and in other cases hands and feet—help dissipate heat better and are more favorable in hot environments.

Skin color is a genetic adaptation related to UV radiation. Drag and drop the skin color to the latitude where it is found.

0-20: Dark skin 60-80: Light skin

Place the following human life history stages in chronological order of growth and development.

1.) The prenatal stage feedback: This is the first stage. It occurs in the mother's womb, before birth. 2.) The postnatal stage feedback: This is the second stage. It occurs after a human exits the mother's womb, but before a human can make babies of his or her own. 3.) The adult stage feedback: The adult stage is the third and final stage. It occurs after a human has grown and developed into sexual maturity.

The map above shows B blood group frequencies across eastern Asia and far western Europe. There is a gradual change in the characteristic from one population to the next. This pattern is called a ___________.

Cline Feedback: This is a cline, or a gradual change in some characteristic from one population to the next.

Identify the statements that accurately describe the human reaction to heat stress.

Describes Human Reaction to Heat Stress: -Humans depend on sweating to regulate their temperature more than other primates do. feedback: Sweating is most effective in areas of the body without dense hair cover. Humans are unique among the primates because they have very little body hair and therefore sweating in humans is much more effective in cooling the body than in other primates. This is why humans depend on sweat to regulate their temperature more than other primates do. -Humans sweat to lower their body temperature. feedback: Sweating is a response to heat. The human body can produce a remarkable amount of sweat on the body's surface. Evaporation of the thin layer of water on the skin results in cooling. Does Not Describe Human Reaction to Heat Stress: -Human bodies experience vasoconstriction, the narrowing of blood vessels. feedback: Vasodilation is an acute response to high (hot) temperatures. The blood vessels expand near the body's surface, allowing the body to move more blood (and associated heat) away from the body's core. In contrast, vasoconstriction, which is the narrowing of blood cells, occurs in very cold conditions. -The target temperature of the human body changes when the environment changes. feedback: Humans are homeothermic, which means they require a constant body temperature (98.6 °F) to maintain the functionality of their organs. A body temperature above 104-107 °F for an extended period can result in death. Therefore, human bodies must react to hold body temperature constant. -All human individuals have the same capacity to react to excessive heat. feedback: Individuals who have not often experienced extreme heat are less able to conduct heat away from their cores and less able to sweat than are individuals living in hot climates. Furthermore, women are less able to tolerate heat than are men because they have more body fat and a relatively reduced ability to experience vasodilation.

Who was the first scientist to challenge the concept of race?

Franz Boas feedback: Franz Boas, who is also commonly referred to as the founder of American anthropology, was among the first scientists to challenge the taxonomic approach to human biological variation. He conducted his work in the early 1900s.

The following examples are possible physiological and morphological outcomes of high-altitude exposure in humans. Which one is a functional adaptation?

Greater diameter of arteries and veins, and greater relative blood flow to body tissues feedback: This is a functional adaptation. An individual may not be born with the phenotype, but is born with the genetic flexibility or capacity to develop it if he or she is found in high altitudes.

The following table presents three outcomes of solar/UV radiation. Which effect includes a genetic adaptation? Click on your answer.

High melanin production (dark skin) feedback: High melanin production is a genetic adaptation. It is coded in the DNA and can be passed from generation to generation. An individual is born with this adaptation.

What is the adaptive reason for low levels of melanin at higher latitudes?

Lower levels of melanin lead to higher vitamin D absorption at higher latitudes feedback: The body needs UV radiation to synthesize vitamin D, which is important for functions such as bone mineralization (skeletal structure). Because higher latitudes have low UV radiation levels, individuals who live in these environments only benefit if their melanin levels are low and they have light skin.

The tennis player in the picture, Serena Williams, has a dominant right arm, which she uses more frequently than her left arm. Which of the humerus (upper arm bone) cross-sections presented below most likely belongs to her right arm?

Right humerus feedback: This is the woman's right humerus. The bones of the arms and legs become denser, and are able to resist bending and twisting, when they are subjected to more strain due to repeated use. Such rigidity allows them to prevent breaking or fracture during normal use. Note that the cross-section of this humerus has a greater diameter and greater overall bone mass.

Bergmann's rule demonstrates how climate is related to body size and shape. Drag and drop the climate information to where it belongs on the graph.

Taller, narrow body-- Hot climate feedback: To adapt to hot climates, people have to radiate the heat in their bodies more than people found in colder climates. Because our ability to dissipate heat is related to body volume and surface area, in hot climates, individuals have taller and narrower bodies. Shorter, wider body-- Cold climate feedback: To adapt to cold climates, people have to retain the heat in their bodies more than people found in hotter climates. Because our ability to conserve heat is related to body volume and surface area, in cold climates, individuals have shorter and wider bodies.

Below is a list of traits that R. C. Lewontin and subsequent scientists used to test whether there is more genetic diversity (i.e., the difference) between populations (i.e., between races) or within them. What did he find to be true about each trait? Match each trait to the correct statement.

There is more variation within the population than between populations: -blood groups -serum proteins -red blood cell enzyme variants

Human populations that engage in activities that exert physical forces on the skeleton (e.g., walking, lifting, carrying) have bones with optimum density.

True feedback: Although it may seem that putting stress on your bones would make them more brittle, it actually makes them stronger. Bones become denser with more use. If you engage in an activity repeatedly, osteoblasts or bone cells will rebuild at a higher rate than they are destroyed. This is the body's built-in defense system to protect against the potential dangers of everyday life. See an example on the left in the image below.

Identify the ways in which the work of Franz Boas challenged the concept of race.

Way(s) That Boas Challenged the Concept of Race: -By studying traits in both parents and their children, Boas showed that the phenotypic characteristics associated with race can change in a single generation. -By studying traits in immigrants, Boas showed that racial types were not static and differed across different environments. Not Way(s) That Boas Challenged the Concept of Race: -By having a very small study group of immigrants who did not freely interbreed where they migrated, Boas showed that genetic drift could not even change racial markers. -By studying genetic markers, Boas showed that there are larger genetic differences between parents and children than between individuals who look the same.

Variation in skin color is an example of a __________

cline feedback: Skin color transitions along a gradient from equatorial to higher latitudes. Those people who live closer to the equator have darker skin colors and those who live farther away have lighter skin color. Because the clinal distribution of skin color allows us to see that the strongest factor in determining skin pigmentation is exposure to ultraviolet radiation, we know that it is not a marker of distinct racial groups.

How many calories per day are consumed in the majority of human populations across the world?

far fewer than 2,000 feedback: The majority of human populations are undernourished. Most of these populations come from developing nations in Africa, South and Central America, and Asia. These populations not only struggle to receive enough calories to survive, but they are also lacking in micronutrients (vitamins and minerals), which can cause suppressed immune function and susceptibility to disease, stunted growth, shortened life expectancy, and poor general functioning.

The top map presents the distribution of skin pigmentation in indigenous populations, and the bottom map represents the UV radiation. What evolutionary force explains discrepencies between the expected and observed pattern?

gene flow feedback: Although the major selective force that affects skin color is the distribution of UV radiation, the fact that all human populations are one species, modulates the expected distribution by interbreeding between light- and darker-skinned people, creating a cline.

High levels of melanin are adaptive at low latitudes because it allows the body to __________ folate

protect feedback: Folate, which is essential for the synthesis and repair of DNA, is naturally produced in the body. However, it can be destroyed by too much UV radiation. High levels of melanin protect folate so neural tube defects, cleft palate, pregnancy loss, and reduced sperm production do not occur. Without folate protection, reproductive success would be negatively impacted.