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What is environmental Science?
It is the study of how humans interact with the environment
What is the environment?
It includes the natural world as well as things produced by humans!
Environmental Movement: Differing World Views
As you know, the environment has not always been our top priority. It is actually
more of a recent phenomenon.
In Canada, we felt that because we had a large land mass (10 million square
kilometres) which is only 6.7% of the total land mass of the planet, and a smaller
population (30 million) our resources were unlimited and the environment should
not be our concern.
Now we know the environment is important and globally this view has begun to
change.
Two world views towards the environment
Expansionist world view
believed that although wastefulness was to be avoided in a developing society,
nature could be exploited for gains in personal wealth and in the name of progress
Ecologist world view
asserts that all living things are valuable, regardless of their use to humans, and
that any human activity must work within the confines of the healthy Functioning
of the Earth's natural processes.
Environmental History
Industries popped up and expanded
More automobiles were purchased
Environmental problems became obvious i.e. color of air was darker, people
developed more respiratory problems, beaches were filled with garbage and
sewage etc.
Wilderness was beginning to disappear therefore environmental groups were
developed i.e. Sierra Club, Canadian Forest Industry etc.
Two waves of environmentalism
The first wave
- department of the environment developed in Canada
- first earth day celebrated in the US in 1970
- population concerned about
- pollution
- energy crisis
- nuclear power
-
Populations
The Second Wave
population concerned about
- global warming
- ozone depletion
- oil spills
- resource depletion
The Scientific Method
Pure and Applied Science
We use science to help us learn about the environment.
There are two basic types of science:
Pure science seeks to answer questions about how the natural world works. Ex:
Physics and biology
Applied science uses the information provided by pure science to solve problems.
Ex: Engineering and medicine
What is Science?
Science is something you know - it is all the information gathered by scientist
throughout history.
Science is something you do - it is the way of getting the answers about our world.
The way scientists get answer is through the scientific method.
Scientific Method
1) Problem: Identify a problem from what you know
2) Form a Hypothesis: a hypothesis is a prediction of what the correct answer will
be based on what you know
3) Materials: gather and record your materials that you are using
4) Experiment: (Procedure)Test the hypothesis. When testing you need a control
and a variable.
Hypothesis, Theory, Law
A hypothesis is an educated guess. A hypothesis can be supported or rejected.
A theory summarizes a hypothesis that has been supported with repeated testing.
A theory is valid unless there is information to disprove it. A theory tells you why
something happens.
A law is a description of a principle but it does not explain them. Ex: Newton's law
of gravity predicts what happens when an object falls, but not why it falls.
What are our Main Environmental Problems?
Environmental Problems
-Pollution
- Extinction
- Resource Depletion
Resource Depletion
When a natural resource is used up it is called resource depletion. Natural
resources include sunlight,plants,animals, forests and fossil fuels.
Two types of resources:
Nonrenewable resources: resources that cannot be replaced. Ex: Fossil fuels such
as oil and natural gas.
Renewable resources can be replaced such as sunlight, vegetation like corn and
trees.
Pollution
Pollution is the poisoning of our air, water or soil.
Pollutants are such things as car
exhaust, pesticides or radiation.
Extinction
Extinction means that the last individual member of a species has died and the
species is gone forever.
The extinction rate has increase due to habitat destruction and pollution.
Why does this matter to us?
All livings things exist in an area surrounding the Earth called the biosphere.
The biosphere extends 8 km above the surface of the Earth to 8 km below the
surface into the deepest part of the ocean.
Root of environmental problems
Although all humans live in the biosphere, people in different countries have
different immediate needs and priorities.
There are two types of nations:
Developed countries have good industry with high average incomes such as the
US, Canada and Australia.
Developing countries less industry and have lower average
There are two main environmental problems:
Population crisis which means the number of people is growing too quickly for the
Earth to support
Consumption crisis which means people are using up, wasting or polluting natural
resources faster than they can be renewed, replaced or cleaned up.
The Goal of Environmental Science
The goal of environmental science is to achieve a sustainable world where all
populations can continue to exist with a high standard of living and health.
What is an Ecosystem?
An ecosystem includes all the different organisms living in a certain area, along
with their physical environment.
An ecosystem is like a car, all the parts work together to make the car move. If
one part breaks, the car may not run.
Ecosystems are not an isolated unit. They do not have clear boundaries.
Ecosystems are composed of two factors:
biotic factors: living parts of an ecosystem. Ex: animals, plants and micorganisms
abiotic factors: nonliving parts of the ecosytem. Ex: temperature, sunlight,
humidity, water supply and minerals
Ecosystem have a level of organization.
(Smallest) Organism
Population
Community
Ecosystem
(Biggest)Biosphere
organism - an individual living thing
species - a group of organisms that are able to reproduce together and that
resemble each other in appearance, behaviour and internal structure.
Population - a group of individuals of the same species living in a particular place.
Community - a group of interacting populations of different species
Habitat- the place where the organism lives.
Niche- the way of life of an organism. This includes everything an animal does
and how it interacts with everything in its environment.
Ecosystem, Biome, and Biosphere
Before we continue discussing ecosystem structure, we must understand how
everything fits together.
Ecosystem (Smallest)
Biome
Biosphere (Biggest)
How species interact with each other.
Within an ecosystem, different species can affect each other negatively or
positively.
We will look closely at five major types of species interactions:
Predation
Competition
Parasitism
Mutualism
Commensalism
Predation, Predator, Prey
Predation is the act of killing and eating another organism
i.e. a lion kills a zebra
the organism that kills and eats another organism is called the predator
the organism that is killed and eaten is called the prey
Competition
the relationship between species that attempt to use the same limited resources
Animals compete for the limited resources available to them. Resources can
include food, sunlight, space etc.
Parasitism
the relationship between a parasite and its host
Parasites are organisms that feed on or live within another organism without killing
it immediately. However some parasites can lead to death.
Examples of parasites = tapeworm, ticks, fleas, leeches
The organism the parasite infects is called the host.
Can you think of any reason why the parasite may not want to kill its host?
Mutualism
A relationship between two species in which both species benefit
Ex. Anemones and clownfish are known to benefit from each other in an intimate
relationship. The clownfish becomes immune to the stinging nematocysts of the
anemone. The anemone provides protection and food scraps for the fish. The fish
lures other creatures into the anemone's tentacles and may also remove dead and
dying tissue from the anemone.
Commensalism
A relationship between two species in which one species benefits and the other
species is neither harmed nor helped.