Transcript Humans and the Environment

Do Now
• Name/List 3 reasons why the field of
environmental science is important?
Humans and the Environment
Objective: Students will be able to define
sustainability and describe ways to conserve
natural resources.
What is Environmental Science?
• Environmental Science is the study of the
impact of humans on the environment
• It is considered an applied science –
meaning that it focuses on tangible
problems more than theoretical ideas
• Environmental Science is also
interdisciplinary – it involves many areas
of study
• Some of the sciences that are a part of
environmental science are:
– Ecology, chemistry, geology, botany, zoology,
paleontology
– Economics, law, politics, and geography
Population Growth
• The Industrial
Revolution, modern
medicine, and
sanitation all allowed
the human
population to grow
faster than it ever
had before.
Population Growth
• In the past 50 years, nations have used
vast amounts of resources to meet the
worlds need for food.
• Producing enough food for large
populations has environmental
consequences such as habitat destruction
and pesticide pollution.
Population Growth
• Most scientists think that the human
population will almost double in the 21st
century before it begins to stabilize.
What is the current world population?
• Because of these predictions, we can
expect the pressure on the environment
will continue to increase and the human
population and its need for food and
resources grow.
What environmental problems
have you heard of?
3 Categories of Environmental
Problems
1. Resource Depletion
2. Pollution
3. Loss of Biodiversity
1. Resource Depletion
Any natural material used by humans is called a
natural resource
• Renewable resource
– a resource that is
replaced by natural
processes relatively
fast
• Nonrenewable
resource – a resource
that is consumed
much faster than it is
replaced
• A resource is depleted if a large fraction of
the resource is used up much faster than it
can be replaced
• Can nonrenewable resources be
depleted?
• Can renewable resources be depleted?
2. Pollution
• Pollution is an undesired change in air,
water, or soil that adversely affects health,
survival, or activities of humans, or other
organisms
• Pollution happens when wastes are
produced faster than be disposed of and
accumulate in the environment
Biodegradable v. Nonbiodegradable
• Pollutants that can be broken down in the
environment are called biodegradable
• These become a problem when they
accumulate faster than the environment
can break them down
• Can you name some biodegradable
pollutants?
Biodegradable v. Nonbiodegradable
• Non-biodegradable pollutants are those
that cannot be broken down easily or at all
in the environment
• Because they do not break down it’s easy
for them to build up to dangerous levels in
the environment
• Can you name some non-biodegradable
pollutants?
3. Loss of Biodiversity
• Biodiversity – the number and variety of
species that live in an area
• The organisms that share the world with
us can be considered natural resources.
• We depend on them for food, the oxygen
we breathe, and for many other things.
Loss of Biodiversity
• Only a fraction of the hundreds of millions
species that have ever lived on earth are
still alive – most are extinct
• Extinction is a natural process – so why
should people be concerned about
modern extinction of species?
Sustainability
• Sustainability - When human needs are
met in such a way that a human
population can survive indefinitely
• One of the key goals of environmental
science is to achieve sustainability
“The Tragedy of the Commons”
• The main difficulty in solving
environmental problems is the conflict
between short-term interests of individuals
and long-term welfare of society
• Someone has to take responsibility for
maintaining a resource, or it will become
overused and depleted.
Economic Pressures
• Law of Supply and Demand – the greater
the demand for a limited supply of
something, the greater the worth
• Cost-Benefit Analysis – balances the cost
of doing something with the benefits of not
doing it
• Risk Assessment – determination of the
risks of an undesirable outcome
Ecological Footprints
• An ecological footprint shows the
productive area of Earth needed to
support one person in a country
• It includes estimates for :
– Land used for crops, grazing animals, forest
products, housing, waste storage
– Ocean area for harvesting seafood
– Forest area needed to absorb air pollution
Ecological Footprint Activity
• You will calculate your ecological footprint by
taking a survey
• Survey will evaluate your usage in different
categories (water, food, energy, etc.)
• Assign yourself points based on the answer
choice that BEST matches your routine
• Add all points together and divide by 300 to get
your ecological footprint
Exit Ticket
• List the three categories of environmental
problems. Give one example of each.