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Chapter 17. Lessons From the Past, Lessons For the Future. Lessons from the Past & for the Future. How Successful Are We? Humans are animals Religious views Exploitation of resources Reproduction # of Species Longevity. Culture as an adaptive strategy Emergence of Agriculture.
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Chapter 17 Lessons From the Past, Lessons For the Future
Lessons from the Past & for the Future • How Successful Are We? • Humans are animals • Religious views • Exploitation of resources • Reproduction • # of Species • Longevity
Culture as an adaptive strategy Emergence of Agriculture. Increased sedentism. Health & nutrition Infectious diseases Where humans meant to live the lifestyles we live today? Impact of Humans
The Loss of Biodiversity • What is biodiversity? • Loss of biodiversity. • Geological record: 15+ mass extinction over the past 570 million years.
Mass Extinction Events • 1st- 250 m.y.a.- climatic change-landmasses into one supercontinent. • 2nd - 65 m.y.a. ended 150 million years of evolutionary processes that produced the dinosaurs. (impact of an asteroid). • 3rd- Occurring now-large mammalian species-pushed toward extinction by humans (Pleistocene 10,000y.a.) • In North America, at least 57 mammalian species became extinct, including the mammoth, mastodon, giant ground sloth, saber-toothed cat, several large rodents, and numerous grazing animals
Extinction • Species disappearing • Reasons • Rainforest deforestation • Contributes to global warming- absorption of carbon dioxide. • Burning trees as land is cleared- +carbon dioxide. • An estimated 20% of all carbon dioxide emissions are accounted for by the burning of the Amazon rain forest alone. • Could humans become extinct?
Overpopulation • Main problem facing humanity • Reasons? • 10,000 years ago-about 5 million people. • By 1650- 500 million • By 1800- 1 billion. • Between 10,000 years ago and A.D. 1650 population size doubled 71 times. • 50% are under 15 yrs. old
Overpopulation • Dates and associated population estimates up to the present are as follows: • mid-1800s, 1 billion • 1930s, 2 billion • mid-1960s, 3 billion • mid-1980s, 4 billion • present, 6 billion
The Greenhouse Effect And Global Warming • Activities- produce waste and pollution-environmental degradation. • Energy for human activities is derived from burning of fossil fuels. • Burning fossil fuels releases carbon dioxide into the atmosphere- traps heat. • Effects of deforestation • Results
Global Warming • Kyoto Protocol • Since 1860- 1990s hottest decade. • 2002 -the warmest year on record,1998 as second. • 2003 in Europe- hottest on record. • temperature reached 100°F in London.
Climate Change • The average surface temperature of the earth increased by 0.8 C (1.4F)between 1961 and 1990. (U.N. Intergovernmental Panel on Climate Change) • An increase in the mean annual temperature worldwide of 0.5–1°C(.9-1.8 F) could result in melting of the polar caps and flooding of coastal areas. • Experts believe Greenland’s ice sheet will disappear if temperatures increase 3.0°C (5.4 F). • This could raise sea levels by as much as 23 feet over the next 1000 years.