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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
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 2
2. Tolerance ranges to variable conditions (Fig. 6-1):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 3
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 4
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 5
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 6
6. The “single-stressor” model (Fig. 6-2):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 7
7. Elaborated single-stressor model:
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 8
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
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 9
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 10
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).
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 11
11. Physiological responses & acclimatization - differences between Australian aborigines & European immigrants (Fig. 7-6):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 12
12. Single-stressor model of human adaptation to cold (Fig. 7-7):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 13
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”
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 14
14. Single-stressor model of human adaptation to humid heat (Fig. 7-12):
Bergmann’s rule���= pygmy?
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 15
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 16
16. Altitudinal changes in conditions in Hawaii (Fig. 8-2):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 17
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.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 18
18. Distribution of high-altitude regions (Fig. 8-5):
Most effective���adaptations to
altitude
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 19
19. Single-stressor model of human adaptation to high- altitude hypoxia (Fig. 8-6):
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 20
20. Natural hazards:
• Density-independent: – Storms – Blizzards – Tropical cyclones (hurricanes & typhoons) – Tornadoes – Earthquakes – Tsunamis – Volcanic eruptions
• Density may influence outcomes.
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 21
21. Vesuvius and Pompeii - AD 79: http://volcano.und.nodak.edu/vwdocs/volc_images/img_vesuvius.html
BIOS 5445: Human Ecology Dr. S. Malcolm Lecture 6: Slide - 22
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.