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

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?

Map of Deforestation

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

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 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.