The Environment Has Changed Through Time

1
The Environment Has Changed Through Time

• Humans change any environment they have inhabited
  by
• - hunting
• - farming
• - developing the land

Manhattan, NYC 1609 vs. Manhattan, NYC 2009
2
Ex The Extinction of Large Mammals

• At the end of the last Ice Age, many large
  mammals (like the Wooly Mammoth) became extinct
  in North America. Scientists are not exactly
  sure why large mammals went extinct, but the
  extinction coincides with the arrival of humans.
• Think Pair Share
• 1) How might humans have
• contributed to the extinction?
• 2) What other factors might
• have contributed to the extinction?

3
Human Changes to the Environment
Description Effects on Environment Effects on Society
Hunter - Gatherer
Agricultural Revolution
Industrial Revolution
4
Spaceship EarthEarth has been compared to a ship
traveling through space

• Earth is a closed system
• - nothing comes in (except solar energy)
• - nothing goes out (except excess heat)
• Problems
• - some resources are limited
• - no where to put excess wastes

5
How big is the problem?

• Although Earth is a complete system,
  environmental problems can occur on different
  scales.

Local effects individuals or small
communities Regional effects large areas
potentially hundreds of miles apart (sections of
countries or entire nations) Global effects the
entire world
6
Think Pair - Share

• Categorize the following environmental problems
  as local, regional, or global
• A new landfill construction
• Township insect spraying
• Smog
• Release of ozone depleting chemicals
• Wildfires
• Excessive burning of fossil fuels

7
Why are environmental concerns pressing now more
than before?

• Human population growth increased due to
• The Agricultural Industrial Revolutions
• Development of sanitation modern medicine
• Environmental concerns from population growth
• Overuse of natural resources
• Habitat destruction
• Pollution

8
Main Environmental Problems1- Resource Depletion

• Natural Resource any natural material used by
  humans
• - Renewable Resources can be replaced
  relatively quickly by natural processes (plants,
  animals, air, water, soil, etc.)
• - Nonrenewable Resources form at a much
  slower rate than they are consumed - once it is
  used up, it will take millions of years to
  replenish it (fossil fuels, minerals, gems)

9
Main Environmental Problems1- Resource Depletion

• Resources are considered depleted when a large
  amount of the resource has been used up.

Deforestation Excessive Mining
10
Renewable or Nonrenewable?

• 1) Trees 5) Coal
• 2) Gold 6) Diamonds
• 3) Chickens 7) Notebook
• 4) Groundwater 8) Lightbulb

11
Main Environmental Problems2 - Pollution

• Pollution an undesired change in air, water, or
  soil that negatively affects the health,
  survival, or activities of living organisms.
• Biodegradable pollutants can be broken down by
  natural processes (ex sewage, food waste)
• Nondegradable pollutants cannot be broken down
  by natural processes (ex mercury, lead, plastics)

12
Main Environmental Problems2 - Pollution

• Pollutants that do not break down easily can
  build up to dangerous levels in the environment

Air Pollution Water Pollution
13
The big G.W.

• How is air pollution related to global warming?

14
Main Environmental Problems3 Loss of
Biodiversity

• Biodiversity the number and variety of species
  that live in an area
• Endangered Species - a plant or animal species
  existing in such small numbers that it is in
  danger of becoming extinct (ex bald eagles)
• Mass Extinction a large-scale coming to an end
  or dying out (ex 250 mya, over 90 of all
  species became extinct)

15
Main Environmental Problems3 Loss of
Biodiversity

• Once theyre gone theyre gone

Humans are more dependent on species than they
might know we depend on organisms for food,
oxygen to breathe, and potential economic,
scientific, and recreational uses, among others.
16
Tasmanian Tiger

• The last known Tasmanian Tiger died in captivity
  in an Australian zoo in 1936. It was officially
  declared extinct in 1986.
• Why do you think people should be concerned with
  the modern extinction of an individual species
  like the Tasmanian Tiger?