BIOS 5445: Human Ecologyhomepages.wmich.edu/~malcolm/BIOS5445-humanecology... · 2014-01-08 · Dr....

BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 1

•  Lecture 6. Human niche dimensions: –  Lecture summary:

•  Tolerance ranges. •  Stress and physiological response. •  Adaptations. •  Conditions, work and physiological fitness. •  Natural hazards (e.g. Vesuvius).

BIOS 5445: Human Ecology Dr. Stephen Malcolm, Department of Biological Sciences

Pompeii and Vesuvius

Herculaneum & Vesuvius

Vesuvius erupting 1944

http://volcano.und.nodak.edu/vwdocs/volc_images/img_vesuvius.html


2. Tolerance ranges to variable conditions (Fig. 6-1):


3. Niche dimensions:

•  Stiling (2002): –  Fig. 8-20. –  2-dimensional

niche overlap –  Homo sapiens

could be described by the yellow niche:

•  massive overlap with other species.

•  Likely competitive exclusion of species b.


4. Physiological responses to conditions:

•  Stress from physical and biological factors generates a biological response.

•  Internal homeostasis can be disrupted by:

– Heat, pressure, humidity, radiation, pollution. – Predators, parasites, food resource

availability.


5. Human adaptability:

•  Genetic variation. •  Phenotypic plasticity:

– Reversible such as seasonal acclimatization. – Non-reversible such as developmental

adaptations. •  Demographic adjustments:

– e.g. density-dependent effects. •  “Nature vs nurture:”

– gene x environment interactions.


6. The “single-stressor” model (Fig. 6-2):


7. Elaborated single-stressor model:


8. Adaptation to cold and heat:

•  Thermoregulation: –  Balance (Δ S) between heat gain & heat loss

(homeostasis). –  Heat gain through:

•  Metabolic activity: –  Basal + active

metabolism. •  Heat exchange

through body surface via:

–  Conduction K –  Convection C –  Radiation R –  Evaporation E

Fig. 2.6. Begon et al. (2006) Δ S = Mb + Ma + K + C + R - E


9. Cultural adaptations to cold:

•  Protection: –  Clothing & insulation:

•  1 clo = 0.155°C/m2/W (thermal resistance). –  warmth of WWII business suit. –  Inuit clothing = 7-12 clo units.

–  Housing: •  e.g. Inuit igloo & Athapaskan Quin-zhee.

•  Behavior/culture: –  Increased activity. –  Fire. –  Groups, sharing body heat. –  Heated foods & water.


10. Biological adaptations to cold:

•  Insulative adaptations - body size/form & blood flow: –  Minimized ratio of body surface area:volume

•  Bergmann’s rule (1847) - larger body size of homeothermic species in colder climates.

•  Allen’s rule (1877) - shorter extremities of homeotherms in colder climates.

•  Both appear to apply to humans. –  Subcutaneous fat could be adaptive. –  Vascular responses - constriction, dilation and heat exchange.

•  Metabolic adaptations: –  Voluntary muscle use - movement. –  Involuntary muscle use - shivering. –  Nonshivering thermogenesis - hormonal responses that

increase basal metabolism through lipid use (e.g. Ama divers).


11. Physiological responses & acclimatization - differences between Australian aborigines & European immigrants (Fig. 7-6):


12. Single-stressor model of human adaptation to cold (Fig. 7-7):


13. Single-stressor model of human adaptation to dry heat (Fig. 7-9):

“mad dogs & Englishmen go out in the midday sun”

High ratio of eccrine:apocrine��sweat glands

Homo sapiens is probably��best adapted to dry heat:��“the naked ape”


14. Single-stressor model of human adaptation to humid heat (Fig. 7-12):

Bergmann’s rule��= pygmy?


15. Adaptation to altitude:

•  High altitude hypoxia: – Lower barometric pressure and so less

oxygen (Fig. 8-2). – Other stresses include:

•  High ultra-violet radiation (Fig. 8-2). •  Diurnal cold (Fig. 8-2). •  Aridity. •  Isolation and rugged terrain. •  Poor soils & low biodiversity.


16. Altitudinal changes in conditions in Hawaii (Fig. 8-2):


17. Physiological responses to altitude (Fig. 8-3):

•  Oxygen transfer –  To lungs:

•  Increased ventilation rate: –  Fig. 8-3.

•  Loss of body fluid acidity through exhaled CO2 reduces ventilation.

•  Acclimation restores balance. –  From lungs to blood

•  Increased lung pressure & enlarged right ventricle.

•  Polycythemia: –  Increased red blood cells

–  Transport in blood •  Changes in heart rate and supply

–  From blood to tissues •  Less “sticky” hemoglobin.

•  Cellular changes in oxygen use.


18. Distribution of high-altitude regions (Fig. 8-5):

Most effective��adaptations to

altitude


19. Single-stressor model of human adaptation to high- altitude hypoxia (Fig. 8-6):


20. Natural hazards:

•  Density-independent: – Storms – Blizzards – Tropical cyclones (hurricanes & typhoons) – Tornadoes – Earthquakes – Tsunamis – Volcanic eruptions

•  Density may influence outcomes.


21. Vesuvius and Pompeii - AD 79: http://volcano.und.nodak.edu/vwdocs/volc_images/img_vesuvius.html


22. References: •  Begon, M., C.R. Townsend, & J.L. Harper. 2006. Ecology: From

individuals to ecosystems. 4th edition. Blackwell Science, Oxford, 738 pp.

•  Cavalli-Svorza, L.L., & F. Cavalli-Svorza. 1995. The great human diasporas. The history of diversity and evolution. Perseus Books, Cambridge MA, 300 pp.

•  Fagan, B. 2000. The little ice age. How climate made history 1300- 1850. Basic Books, New York. 246 pp.

•  Glantz, M.H. Currents of change. Impacts of El Niño and La Niña on climate and society. 2nd edition. Cambridge University Press, 252 pp.

•  Kormondy, E.J., & D.E. Brown. 1998. Fundamentals of human ecology. Prentice Hall. 503 pp. (chapters 6, 7 & 8).

•  Livi-Bacci, M. 1997. A concise history of world population. 2nd edition. Blackwell Publishers Inc., Malden MA, 249 pp.

•  Stiling, P. 2002. Ecology. Theories and applications. 4th edition. Prentice Hall, Upper Saddle River, NJ, 403 pp.

BIOS 5445: Human Ecologyhomepages.wmich.edu/~malcolm/BIOS5445-humanecology... · 2014-01-08 · Dr....

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