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

Impact of Humans  Culture as an adaptive strategy  Emergence of Agriculture.  Increased sedentism.  Health & nutrition  Infectious diseases  Where humans meant to live the lifestyles we live today?

The Loss of Biodiversity  What is biodiversity?  Loss of biodiversity.  Geological record: 15+ mass extinction over the past 570 million years.

Mass Extinction Events  1 st m.y.a.- climatic change-landmasses into one supercontinent.  2 nd - 65 m.y.a. ended 150 million years of evolutionary processes that produced the dinosaurs. (impact of an asteroid).  3 rd - 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?

Map of Deforestation

Overpopulation  Main problem facing humanity  Reasons?  10,000 years ago-about 5 million people.  By million  By billion.  Between 10,000 years ago and A.D 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

Line Graph Depicting Exponential Growth of Human Population

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 s hottest decade.  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 (U.N. Intergovernmental Panel on Climate Change)  An increase in the mean annual temperature worldwide of 0.5–1°C( 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.