Modern Human Variation 2 Flashcards
human adaptability
- have high phenotypic diversity
- however there is very little genetic diversity on modern H. sapiens; have less variation than closest primitive relatives despite larger population size
gene x environmental interactions
- phenotypes result from genotype and environmental interactions
what is a driver of change in human adaptability
- stress
- homeostasis
homeostasis
any self-regulating process by which an organism tends to maintain stability while adjusting to conditions that are best for its survival
responding to external factors/challenges
- behavioural
- cultural
- genetic
acclimatization
- individual level
- short term
- Reversible
adaptation
- population level
- long term/evolutionary
Developmental/phenotypic plasticity of human adaptability
- individual level
- adaptive process
- short-term or long-term
behavioural and cultural of human adaptability
- population and individual level
- long-term
growth and development
- adaptation and plasticity
- secular trends
- developmental process and landmarks
- growth; hyperplasia , hypertrophy
hyperplasia
a process that involves the increase in cell production in a normal tissue or organ, and can occur during development and maturation
hypertrophy
increase in size of cells or tissues in response to various stimuli, including exercise and injury
anthropometry
the scientific study of the measurements and proportions of the human body
scammon curves
tracking growth of different parts of the body
distance curves/height-for-age
- a graph that shows the height or other growth achieved at a given age
- growth reference standards; standard deviation
- normal growth = 0 SD
stunting = -2 SD or lower
weight for age curves
- attainment of weight relative to age
- growth reference standards
- underweight = -2 SD
- also measured relative to height; wasting, overweight
endocrine system and hormones
- cortisol
- growth hormones (pituitary gland)
- sex hormones (testosterone, estrogen)
onset of puberty
- 8-9 for females
- 10-11 for males
- development and emergency of secondary sexual characteristics
factors that comprimize growth
- nutrition; quality, quantity
- stress; disease loads, psychosocial and socioeconomic stress
developmental/phenotypic plasticity of growth and development
- environmental influences
- moderation of growth and development
- variable responses between individuals
nutrition in growth and development
- macronutrient deficieny; kwashiorkor, marasmus
- comprimises in height and weight; stunting, wasting
- micronutrient deficiency; lack of vitamins and minerals
Disease in growth and development
- infectious disease ex. cholera
stress in growth and development
- psychosocial or socioeconomic stress
- ex. marginalization, poverty
genetic variation in growth and development
- growth hormone deficiencies
- excess growth
can we recover after a negative episode?
- catch-up growth
- compensation varies with timing of stressors
when is growth and development the most important
- first 1000 days
- critical window in terms of growth and development
- early life influences have later life impacts
climate
- range of responses to climate variation; acclimation, adaptation
cold stress acclimation
- vasoconstriction to conserve hear
- skin/hair reactions
- shivering thermogenesis
- hunting phenomenon
- behaviour: cold mitigation/avoidance
hunting phenomenom
phenomenon that occurs in the skin when it’s exposed to cold. It’s characterized by alternating vasoconstriction and vasodilation in the extremities
heat stress acclimation
- vasodilation; radiation, convection, conduction
- sweating (evaporation)
climate adaptation bergmann’s rule
- size/body mass
- animals adapted to colder climates are larger, while those adapted to warmer climates are smaller
climate adaptation allen’a rule
- shape/limb length
- animals adapted to colder climates have shorter and thicker limbs compared to animals in warmer climates
issues with bergmann’s and allen’s rule
- katzmarzyk and leonard
- was there research bias? northern hemisphere and wealthier countries
- can change in nutrition also have effect
ex. edo individuals with a larger body size lose less heat from the hands than those with a smaller body size?
do individuals with more muscle mass or more fat mass lose less heat from the hands?
result: skeletal muscle mass relative to body mass was a highly significant predictor of heat loss, body/fat mass and stature were not
altitude
changes at greater altitude have implications for human body functions; barometric pressure, hypoxia
altitude sickness
- hyperventilation
- changed sleep patterns
- increased urination
- headache
- loss of appetite
- nausea
- fatigue
other challenges of altitude
- uv radiation
- cold temperature
- low humidity
- resource losses
altitude acclimation
- red blood cell numbers increase
- haemoglobin encouraged to release more oxygen
- increase in cardiac output
- increase in capillary network
- hyperventilation
- cellular metabolic changes
physiological adaptions of altitude in different climates
- tibet: increased blood flow with low oxygen saturation
- andes: respiration and haemoglobin increases
- ethiopia: oxygen uptake and delivery
