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Lactose
enzyme that allows you to digest lactose, which is a sugar in milk
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Lactose intolerance
Insufficiency in lactase
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Populations with long history of dairying are generally _____
lactose TOLERANT
(Mutation for ability to digest milk as adults would have provided an natural selective advantage)
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phenotypically different populations in a species
polytypism
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Polytypism is a result of ____ of environments that we inhabit.
Our populations diversify phenotypically (and genetically) because of _______, but our pops. remain within a single species because of _____.
diversity
- natural selection,
- gene flow.
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not a biologically useful grouping of humans
Race
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Two problems with the concept of race:
1.
2.
- 1. Failure to understand genetic basis for phenotypes
- 2. Researchers differ in identification of the # of races
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result of natural selection
Evolutionary perspective
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Any beneficial modification that relieves environmental stress & enhances survival of individuals
Human variation perspective
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Types pf adaptations (4)
- Behaviors
- Short term (reversible) acclimatization
- Developmental (irreversible) acclimatization
- Genetic (result of natural selection)
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Physiological & anatomical adjustments to the environments that occur during an individuals lifetime
Acclimatization
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Info on Pigmentation
Pigment is ____
Melanin is produced in ____, which are in epidermis of skin
Melanosomes are transferred to _____, which are also in epidermis
- melanin,
- melanocytes,
- keratinocytes
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All people have the same number of melanocytes
True)
False)
True
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Compared to lightly melanized individual, heavily melanized individuals:
1. Produces ____ melanosomes
2. Has ____ melanosomes
3. Melanosomes are ___ dispersed in keratinocytes
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Dark Skin Pigmentation
Adaptive in areas of intense UV radiation
melanin functions to absorb UV radiation
Reduces likelihood of cancer
Light Skin Pigmentations
Adaptive in areas of low UV radiation
Allows sufficient synthesis of vitamin D
Reduces likelihood of rickets
.
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Among populations within a species, body mass is higher in areas w/ lower temperatures
Bergmann's Rule
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Among populations within a species arms & legs are shorter in areas w/ lower temperatures
Allen's Rule
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Populations living in _____ temperature environments show an "extremities" adaptation
Higher basal metabolic rate
Efficient cycling of vasoconstriction and vasodilation
Maintain higher temperature of fingers and toes
Low temperatures
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Populations living in ____ temperature environments show a "hypothermic" adaptation
Lower vasal metabolic rate
High temperature
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A stress of high altitude
Hypoxia (Low atmospheric oxygen levels)
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Increase concentration difference of oxygen between lungs & blood
Hyperventilation
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Increase # of "vehicles" for picking up & carrying oxygen
Increase red blood cell produciton
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Releases oxygen from hemoglobin, thereby maintaining concentration gradient for diffusion for oxygen from blood cells
Increase in 2.3-DPG
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Increase surface area for diffusion of oxygen from blood cells
Increase number of blood vessels
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