Human Ecology I Flashcards

Question

A history of responses to environments

Answer 1

Largely, species wide adaptations to environment until 100-70 KYA within Africa & response to climate changes. Out of Africa: Some population wide & serial adaptations to differing environments (H. erectus as well as e.g. 1) before humans arrive in western hemisphere, first experience environment of north Asia 2) moving north & south => seasonal environs Also: Acclimatization and aclimation = plastic response to varying environments (reversible physiological responses)

Answer 2

Humans are organisms who conform to laws of physics and the same basic requirements of most other living organisms - particularly mammalian organisms with whom we share millions of years of evolution. Energy obtained from the sun via photosynthesizers (plants). Laws of thermodynamics Energy transformation Entropy (organization requires energy) Heat production through metabolism Examples of adaptation to abiotic factors

Answer 3

Organisms transform energy into biomass (metabolism, biomass, offspring) Transformation requires energy & specific resources that vary e.g. plants require CO2, minerals, water and light to photosynthesize animals require 02, water, minerals, carbon source (fixed energy), etc

Answer 4

1st law of thermodynamics: conservation of energy in the conversion of energy from one form to another, energy is neither lost nor gained from a system Think of biomass as standing stocks of energy Can't make new energy except through capture of solar energy. Energy is fixed via photosynthesis by plants

Answer 5

2nd Law of Thermodynamics: energy conversions result in a loss of free energy in the system (increased entropy) or: it costs energy to maintain organization of systems because they naturally go toward a state of disorder.... Conversions of biomass cost energy: e.g. more energy arrives from sun than is converted by photosynthesis to plant biomass, plant biomass to herbivores, herbivores to carnivores, etc... e.g. conversion of foods to animal biomass requires energy for metabolic processes to occur it takes energy to maintain biomass organization

Answer 6

LEIBIG'S LAW OF THE MINIMUM: Distribution of a species is controlled by that environmental factor for which the organism has the lowest range of adaptability or control E.g. No water => no human occupation (unless provided artificially) even if food IS somehow available. Related: Numbers will decline with decrease in levels of required nutrients.

Answer 7

Distribution of a species is controlled by that environmental factor for which the organism has the lowest range of adaptability (how well can it do with low or no levels) or control (ability to acquire resource) If you supplement that lowest factor, then the next lowest becomes limiting

Answer 8

No organism can live under every condition : Geographical distribution is determined by upper and lower bounds of physical tolerance Shelford 1913 Outside of these boundaries don't find the organism; Obvious example: no oxygen => no human habitation Biological adaptation (e.g. body size to cold) Humans: Cultural adaptation (e.g. clothing is a cultural adaptation that increases tolerance to cold environment)

Answer 9

CARRYING CAPACITY (K) = maximum population size of a biological species that can be sustained by that specific environment. LIMITING FACTOR & K: Change in level of resource results in change of carrying capacity (individuals per square area) REGULATING FACTOR: Change in level of factor changes vital rates (birth rate, death rate) as population density increases (e.g. death due to cholera or Covid-19 increases with population density)

Answer 10

Selection tends to occur near the edges of tolerance or minimums e.g. tolerance for starvation Selection for ability to survive on less food to slow growth, to reduce reproductive rate, migrate out of area where food is scarce

Answer 11

Many species wide adaptations clearly responses to abiotic environment e.g. Temperature e.g. body size, fur & underfur UV Radiation skin coloration hair ? body coverings

Answer 12

Bergmann's Rule: Larger bodies (trunks) evolve in colder temperature Why? Produce our own heat Require body temp near 37 degrees Ambient equilibrium = 29 degrees In cold temperatures need to conserve heat to maintain body temperature Lose heat from surface Larger body has less surface area per volume for heat dissipation

Answer 13

Bergmann's rule - Body size of homeotherms increases with decreasing mean temperature Humans better adapted to tropical than to temperate or arctic environments longer evolution in warm climates

Answer 14

The problem is excessive heat build-up core burns energy producing heat which must be dissipated hot environment -> little thermal gradient You don't have any content yet. Adaptations Large surface area : volume Small trunk and elongated appendages Higher surface area / volume ratio

Answer 15

(English / cold temperate latitude) anthropologist Colin Turnbull with Mbuti people from the Ituri forest (hot, humid) Reduced expression of Growth Hormone Receptor Many exceptions and complications - Different ways to adapt - Dry versus humid heat - Diet and energy requirements - Recent migrations Is climate the only reason for body size and shape variation?

Answer 16

Length of appendages of mammals decreases with decreasing mean temperature

Answer 17

Layers of loose clothing (insulation) reduce exposure to UV and reduce water loss

Answer 18

Patterns of adaptive responses to some abiotic selective pressures are relevant to some inter-population variations. These adaptations must have occurred since dispersal out of Africa (within last ~70KYA) The selective pressures result in clines of variation related to the environmental gradient of the relevant selective pressure Body size, size of extremities, and skin colour demonstrate clinal variation correlated with environmental variation These adaptations are specific applications of "laws" of ecology and biological adaptation that apply to most homeotherms