Lessons From the Past, Lessons For the Future

1
Chapter 14

• Lessons From the Past, Lessons For the Future

2
Chapter Outline

• How Successful Are We?
• Humans and the Impact of Culture
• The Loss of Biodiversity
• The Present Crisis Our Cultural Heritage?

3
Neolithic

• The period during which humans began to
  domesticate plants and animals.
• The Neolithic is also associated with increased
  sedentism.
• Dates for the Neolithic vary from region to
  region, depending on when domestication occurred.

4
Mesolithic

• The period preceding the Neolithic, during which
  humans increasingly exploited smaller animals
  (including fish), increased the variety of tools
  they used, and became somewhat less nomadic.

5
Map of Deforestation
6
The Loss of Biodiversity

• Biodiversity is the totality of all living
  things, from bacteria and fungi to trees and
  humans.
• We are currently losing biodiversity, but we
  dont know the exact rate of loss or what its
  impact will be.
• The geological record indicates that in the past
  570 million years, there have been at least 15
  mass extinction events, two of which altered all
  of the earths ecosystems.

7
Mass Extinction Events

• The first occurred 250 million years ago and
  resulted from climatic change following the
  joining of all the earths landmasses into one
  supercontinent.
• The second event happened 65 million years ago
  and ended 150 million years of evolutionary
  processes that produced the dinosaurs.
• This is believed to be the result of climate
  changes following the impact of an asteroid.

8
Mass Extinction Events

• A third major extinction event is occurring now,
  and may have begun in the late Pleistocene or
  early Holocene
• Many scientists believe several large mammalian
  species were pushed toward extinction by humans,
  near the end of the Pleistocene, some 10,000
  years ago.
• 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.

9
Overpopulation

• Scientists estimate that around 10,000 years ago,
  only about 5 million people inhabited the earth.
• By A.D. 1650, there were perhaps 500 million, and
  by 1800, 1 billion.
• Between 10,000 years ago and A.D. 1650 population
  size doubled 71 times.

10
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

11
Line Graph Depicting Exponential Growth of Human
Population
12
The Greenhouse Effect And Global Warming

• Activities involved in the production of goods
  and services produce waste and pollution, all of
  which leads to environmental degradation.
• Much of the energy used for human activities is
  derived from burning of fossil fuels.
• Burning fossil fuels releases carbon dioxide into
  the atmosphere, and this, in turn, traps heat.

13
Deforestation

• Deforestation contributes to global warming,
  since were reducing the number of trees
  available to absorb carbon dioxide.
• In the tropics, trees are burned as land is
  cleared, a practice that releases yet more carbon
  dioxide.
• An estimated 20 of all carbon dioxide emissions
  are accounted for by the burning of the Amazon
  rain forest alone.

14
Climate Change

• Since records began being kept in 1860, the 1990s
  were the hottest decade, followed closely by the
  1980s.
• The year 2002 had the distinction of being the
  warmest year on record, with 1998 running a close
  second.
• The summer of 2003 was the hottest on record in
  Europe, and for the first time in recorded
  history, the temperature reached 100F in London.

15
Climate Change

• According to the U.N. Intergovernmental Panel on
  Climate Change, the average surface temperature
  of the earth increased by 0.8 C between 1961 and
  1990.
• An increase in the mean annual temperature
  worldwide of 0.51C could result in melting of
  the polar caps and flooding of coastal areas.
• Experts believe Greenlands ice sheet will
  disappear if temperatures increase 3.0C.
• This could raise sea levels by as much as 23 feet
  over the next 1000 years.

16
Quick Quiz
17

• 1. The population of the world today is around
  ______ billion.
• 2
• 4
• 6
• 10

18
Answer c

• The population of the world today is around 6
  billion.

19

• 2. The adaptive strategy of humans has always
  been
• fight or flight.
• culture.
• aggression.
• expansion.

20
Answer b

• The adaptive strategy of humans has always been
  culture.

21

• 3. In the past 570 million years, there have been
  ______ mass extinctions.
• 4
• 10
• 15
• 21

22
Answer c

• In the past 570 million years, there have been 15
  mass extinctions.

23

• 4. The problem that is linked to all other life
  forms and is therefore the most important problem
  facing human beings is
• population increase.
• competition for resources.
• polluted air.
• loss of biodiversity.

24
Answer a

• The problem that is linked to all other life
  forms and is therefore the most important problem
  facing human beings is population increase.