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Role of Resources, Behavior and Disease in Shaping the Human Population

Role of Resources, Behavior and Disease in Shaping the Human Population. A Historical Perspective. Disease. Defects that cause disease now might have just been simple variations. May have been harmless or useful but are harmful now. http://www.daviddarling.info/images/DNA.jpg. Disease.

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Role of Resources, Behavior and Disease in Shaping the Human Population

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  1. Role of Resources, Behavior and Disease in Shaping the Human Population A Historical Perspective

  2. Disease • Defects that cause disease now might have just been simple variations. • May have been harmless or useful but are harmful now. http://www.daviddarling.info/images/DNA.jpg

  3. Disease • James Neel: In the ancient environment humans needed a “thrifty gene.” • In modern times however, in the Western World, humans don’t require reserves of glucose. • Explanation for obesity and diabetes.

  4. James V. Neel Source: http://www.scielo.br/img/fbpe/gmb/v23n3/4349f1.jpg

  5. Behavior • The behavior of our ancestors can also be a factor in explaining the modern human populace.

  6. Bipedalism • Resources forced our ancestors to turn to bipedalism. • Bipedalism causes some problems: • Examples: Prenatal & Birthing problems, back aches, knee problems. Source: http://www.crystalinks.com/lucypaleon2.jpg

  7. Depression • Depression: social technique dating back to the ancient environment. http://www.drjoecarver.com/clients/49355/1053332_org.jpg

  8. Theories about Depression • Various theories: • Nesse: Depression a strategy to conserve energy and resources. • Allen and Badcock: Signaled to dominant individuals that the depressed individual was not a threat and needed support.

  9. Depression in the Modern World • In the modern world depression may no longer be useful because humans live in a non-hierarchal environment that is much more isolated. http://upload.wikimedia.org/wikipedia/commons/d/db/NYC-Skyline-1.jpg

  10. Stress • Stress may also have been beneficial to ancient humans, explaining why it still exists. • Stress prepares the body to overcome a threat and to then recover from an experience. http://www.worksafesask.ca/files/ont_wsib/certmanual/stress.jpg

  11. Stress in the Modern World • Stress, beneficial to our ancestors may now be harmful to modern humans. • The body secretes adrenaline and cortisol which mobilizes fatty acids and glucose. • Now this is not as necessary and can cause much more harm by contributing to certain disease.

  12. Tool Making • Tools allowed our ancestors to do a lot of things they couldn’t previously do: • Examples: scavenging marrow from bones, extracting termites. • This invention had consequence that have been extremely helpful to the modern human populace.

  13. Adaptations necessary for tool-making • Needed to evolve mobile thumb joints, powerful muscles and large fingertips. • These adaptations allow humans to do things that other animals and even other primates cannot do. http://www.southpalmorthopedics.com/portals/2/MedicalLibraryAssets/Medical/CMCArthroFINAL_small.jpg

  14. Consquences • Humans could vary their diet. Allowed the evolution of a much larger brain, which requires a great deal of nutrients on a daily basis. • Larger brain has benefits such as the ability to reason, the evolution of language and so on. • Natural selection favored those ancient humans with the abilities to make tools. http://www.h4ppy.com/blog/uploaded_images/Jebel%20Acacus%20Cave%20paintings%203-756757.JPG

  15. Consequences • A larger brain itself is helpful to humans. • Debate as to how the brain evolved to become so large. • Bruce Lahn: As society developed, the greater cognitive abilities that a large brain provided were beneficial. • Larger brains could manipulate the social structure and their environment. http://psyweb.com/Brain/Bimages/BW_brain.jpg

  16. Evolution of Language • The ability to speak language for our ancestors provided great advantages. • Communicate ideas, express your needs and even convince others. • Group survival capabilities would be much higher as well. • Noam Chomsky: Those who could use language would be isolated from other groups, result a “new language-based species.” • Evolution of larynx itself shows its importance. • Position of larynx makes humans susceptible to choking. • Variation would not be passed on to another generation, unless a selective advantage such as language existed.

  17. Sources • Barbujani, Guido, and Laurent Excoffier. "The History and Geography of Human Genetic Diversity." Evolution in Health and Disease. Ed. Stephen Stearns. New York: Oxford UP, 1998. 27-40. • Feachem, Richard, and Oliver Sabot. "Surviving disease." Survival : The Survival of the Human Race. Ed. Emily Shuckburgh. New York: Cambridge UP, 2007. 99-122. • Nesse, Randolph M., and George C. Williams. "Research Designs." Evolution in Health and Disease. Ed. Stephen Stearns. New York: Oxford UP, 1998. 16-22. • Pollard, Tessa. Western Diseases: an Evolutionary Perspective. New York: Cambridge UP, 2008. • Richards, Graham. Human Evolution : An Introduction for the Behavioral Sciences. New York: Routledge, 1987. • Strassman, Beverly L., and Robin Dunbar. "Putting the Stone Age in Perspective." Evolution in Health and Disease. Ed. Stephen Stearns. New York: Oxford UP, 1998. 91-101

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