The Environment Has Changed Through

TimeHumans change any environment they have inhabited by: - hunting - farming - developing the land

Manhattan, NYC 1609 vs. Manhattan, NYC 2009

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 mighthave contributed to the extinction?

Human Changes to the Environment

Description Effects on Environm

ent

Effects on Society

Hunter - GathererAgricultur

al Revolutio

n

Industrial

Revolution

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

How big is the problem?• Although Earth is a complete system,

environmental problems can occur on different scales.Local – effects

individuals or small communitiesRegional – effects large areas potentially hundreds of miles apart (sections of countries or entire nations)Global – effects the entire world

Think – Pair - ShareCategorize the following environmental

problems as local, regional, or global:

1. A new landfill construction2. Township insect spraying3. Smog4. Release of ozone depleting chemicals5. Wildfires6. Excessive burning of fossil fuels

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

Main Environmental Problems

1- Resource DepletionNatural 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)

Main Environmental Problems

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

Deforestation Excessive Mining

Renewable or Nonrenewable?

• 1) Trees 5) Coal

• 2) Gold 6) Diamonds

• 3) Chickens 7) Notebook

• 4) Groundwater 8) Lightbulb

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)

Main Environmental Problems2 - Pollution

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

Air Pollution Water Pollution

The big G.W.

• How is air pollution related to global warming?

Main Environmental Problems

3 – 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)

Main Environmental Problems

3 – Loss of BiodiversityOnce they’re gone… they’re 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.

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?