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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. WRONG!!
A Global Perspective
All people hold a set of assumptions regarding the world and how it
works.
Individuals have varying perspectives on the environment, its problems
and how to fix these problems that are dependent on where they live,
their social and economic backgrounds, cultural identity and many other
factors.
World views are sets of commonly shared beliefs, values and ideas
concerning the nature of the world and the role that people play within
it. Every society's world view is reflected in and transmitted through
its culture.
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
Ecological 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
Mid 20th Century
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
First wave 1968 – 1976
- 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
Second Wave- 1985- Present Day
population concerned about
- global warming
- ozone depletion
- oil spills
- resource depletion
Environmental Problems
What are our main environmental problems?
- Pollution
- Extinction
- Resource depletion
Resource Depletion
When a natural resource is used up it is called resource depletion. Natural
resources include all living things, sunlight, air, water, soil, minerals, plants,
forests and fossil fuels.
Some resources can not be replaced, they are called nonrenewable resources.
Fossil fuels such as oil and natural gas can not be replaced because they formed
over millions of years.
Renewable resources can be replaced such as sunlight, vegetation like corn and
trees. Renewable resources can be depleted if they are not given time to
recover.
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.
The root of Environmental Problems
Although all humans live in the biosphere, people in different countries have
different immediate needs and priorities.
The worlds nations can be categorized into one of two groups: developed
countries and developing countries.
Developed countries are highly industrialized with high average incomes such as
the US, Canada and Australia.
Developing countries are less industrialized and have lower average incomes.
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.
In developing countries, the population crisis is most severe because there are more
people than resources.
In developed countries, the consumption crisis is the most severe because people
are overusing the resources.
The Goal on Environmental Science
The goal of environmental science is to achieve a sustainable world where all
populations can continue to exist indefinitely with a high standard of living and
health.
Pure and Applied Science
In order to solve environmental problems, we mus first understand our
environment. The tool that we use to do this is science.
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, and 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 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.
Organism (smallest)
Population
Community
Ecosystem
Biosphere (largest)
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
Niche, and Habitat
Habitat- the place where the organism lives; the specific type of area in which
a plant or animal lives (on the planet).
Niche- the way of life of an organism. This includes the area where the
organism feeds, reproduces etc. It is biotic (living i.e. plants, other animals,
humans) resources
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, and prey
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.
Feeding Relationships, Three trophic levels
Each species in an ecosystem belongs to a certain trophic (feeding) level based on
their main source of nutrition.
In studying the feeding relationships between organisms, we are actually looking at
the living, or biotic, factors of the environment.
Producers
Consists of all plants, may also be called autotrophs.
Has the ability to make its own food through photosynthesis.
Supports all other feeding groups.
Makes up the greatest amount of biomass on the planet.
Eaten by consumers.
Consumers
consists of all animals.
These organisms are not able to produce their own food so they must find their
own food. They are also referred to as heterotrophs.
There are 3 orders of consumers:
1st order = herbivores eat the producers (plants) i.e cow, sheep, deer etc
2nd order = carnivores eat other consumers (animals) i.e. lions, hawks, foxes etc
3rd and 4th = feed on other carnivores in the environment i.e. killer whales
Humans are considered omnivores because we eat both plants and animals. Bears,
pigs and other animals are also omnivores because they eat both.
Decomposers
Life forms that live on dead, dying or decayed plant and animal matter.
Mostly consist of fungi and microscopic organisms, such as bacteria. Scavengers
like ravens, crows etc help decomosers by breaking down dead material.
Essential to the natural environment. They help to recycle nutrients back into the
ecosystem.
They break down animal excretions and dead organisms into simpler components
that can be taken in and reused by producers.
Food Chains
Food chains can be written in a number of different ways, the simplest is: Sun 
producers  consumers
Food Webs
All of the possible feeding relationships within an ecosystem are shown
using a food web.
Summary of food webs and food chains
Within ecosystems there are producers, consumers and decomposers who transfer
energy to one another through food chains or food webs.
Trophic Level = the level in the food chain that an organims occupies. It can be
producer, consumer, primary consumer, etc.
Producers are the 1st trophic level and contain the most energy and each
subsequent level has less and less energy.
Food Chain = simplified way to show which organisms eat one another.
Food web = represents all possible food interactions that can occur between certain
organisms
Optimal Living Conditions
Each species will respond differently to these abiotic factors. The way that they
respond determines where they will live. Different species will do well under
different conditions.
Every organism has an optimum, a level they thrive at. This is called the optimal
zone. i.e. a good amount of water, sun etc.
There is also a point where life is not possible. A high and low end of this range of
optimance and this is the limit of tolerance. If an organism reaches this point they
cannot survive. The stress is too much for them.
Zones of stress exist between the optimal environmental and the high and low
limits. The organism would experience levels of stress as they become closer to
their tolerance limit.
Ecosystem Function
Energy Flow in Ecosystems
What do organisms in an ecosystem require to function?
Nutrients (Matter)
Energy
How do they obtain these nutrients?
Photosynthesis
Respiration
Cycling/Recycling
Key elements of all living things:
-
N (nitrogen)
C (Carbon)
H (Hydrogen)
S (Sulfur)
P (Phosphorus)
O (Oxygen)
These elements make up 95% of all living matter.
In water, air and minerals, atoms are found in relatively simple inorganic
compounds.
Matter and Energy
Matter is the substance that everything is made of. Water, food, soil, computers,
rocks etc all consist of matter.
Matter is anything that occupies space and has mass. This includes all solids,
liquids and gases.
Energy
Energy is the ability to do work and can act on matter.
We use energy to move matter around i.e. we might move a table, chair etc.
Animals in nature might move rocks or tree limbs.
Matter can also be changed from one form to another and energy allows us to do
this i.e. a windmill can convert wind into energy that humans can use.
Photosynthesis
Producers (plants) use photosynthesis to obtain their food and energy.
This is the equation for photosynthesis:
12 H2 0+6 CO2 +sunlight energy=C6 H12 O6+6 H2 0+ O2
Cellular respiration
Consumers (animals and other organsims) use celluar respiration to obtain their
energy
Stored energy from plants and animals is released
During this reaction energy is produced. This energy is used by consumers
The chemical equation for cellular respiration is shown below:
C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy
Does this formula look familiar to you? Where have you seen it before? What is
the relationship between photosynthesis and respiration?
Energy Flow in Ecosystems
All organisms requires energy for growth, maintenance, reproduction, locomotion,
etc...
There are three main types of energy:
Heat Energy
Mechanical Energy
Chemical Energy
Other Types of Energy
-
light
electric
atomic
sound
nuclear
Sources of Energy
In Canada we use 10 basic sources of energy:
-
hydropower (energy from water) i.e. mactaquac dam
nuclear energy (point lepreau)
oil (colson cove)
coal (belldune) and petroleum
natural gas (courtney bay)
solar
biomass
geothermal
wind
tidal and wave
Renewable vs. Non-renewable energy
Non-renewable resource (Exhaustible) - These are energy resources that we can
run out of or be used up
- Examples could be:
o Oil
o Gas
o Coal
o Nuclear Power (uranium)
- Positives for these types of resources are that they are efficient sources of
energy, meaning you can get a lot of energy out of burning a small
amount of these fossil fuels.
- Negatives for these types of resources are that the burning of all fossil
fuels leads to greenhouse gas emissions (dirty), and that their resources
can be used up.
Renewable Resources – These are resources that can be used up, but can also be
replaced or replenished. Meaning as you use the resource, you can also replace the
resources.
- Examples are:
o Wood from trees
o Biomass/Bioconversion for energy – using plants, garbage, and
other living materials for energy. Living material is broken down
using methanol to alcohols which can be used for energy.
- Positives for these types of energy are that their resources can be replaced
when used up.
- Negatives for this type of energy are that burning of wood and release of
gases caused by biomass can lead to emission/pollution. Biomass is also
very inefficient, meaning it takes a lot of living material to produce a
small amount of energy.
Inexhaustible Resources – These are resources that can never be used up, and
cannot be replaced as well.
- Examples are:
o The suns energy – Solar power
o Hydro Power – Power from Dams
o Tidal and Wave – Using the movement of tides for energy
o Geothermal – Earth’s natural heat (hot springs)
o Wind – Wind mill turbines
- Positives for these types of energy are that they have unlimited resources.
You can never use up the sun’s energy, there will always be water
current, and there will always be wind. Also, these types of energy
cause little to no emissions.
- Negatives for these types of energy are that they are very inefficient. It
takes too much conversion of the resource to produce too little energy.
Matter is recycled.
Each organism serves as food for another. Producers eat consumers, consumers
eat other consumers and decomposers feed on the dead and dying.
Therefore all of the nutrients (like carbon, hydrogen, oxygen and nitrogen) which
made up the organism recycle back into the environment.
Cycling of Materials
Energy and matter are recycled in an ecosystem in order for it to function.
Within this matter that is recycled are the key elements.
Each of these key elements is recycled in what is called a cycle. We have the
carbon cycle, water cycle, nitrogen cycle and phosphorus cycle.
The Water Cycle
Energy comes from the sun.
The water cycle has 3 processes:
Evaporation
Condenstation
Precipitation
The sun evaporates the water from ocean, rivers, lakes, soil and from the surface of
leaves into the atmosphere.
When the water vapor reaches the colder air of the atomosphere is condenses back
into liquid water and is stored in the clouds.
When the clouds become filled with this liquid water it is returned to earth as
precipitation (rain, sleet, snow, hail etc). This water collects in rivers, lakes,
oceans or is absorbed into the soil.
The process is then able to begin again.
The Carbon Cycle
Carbon enters the ecosystem through the atmosphere as CO2.
Producers (plants) absorb the CO2 during photosynthesis.
Consumers eat the producers and obtain carbon from them it is then released back
in the atmosphere during cellular respiration.
When animals and plants die and are decomposing, decomposers release the CO2
back into the atmosphere as well through cellular respiration. The remaining
carbon from the dead and decaying organsims is placed into the soil.
Carbon can also be produced by the burning of wood and fossil fuels through
combustion and be released into the atmosphere.
The Nitrogen Cycle
All organisms require nitrogen, however only nitrogen fixing bacteria are able to
use nitrogen gas directly.
Nitrogen fixing bacteria are able to take nitrogen from the atmosphere and
transform it into ammonia.
Plants obtain ammonia through the soil.
Animals obtain ammonia from eating plants.
As plants and animals die and decompose the nitrogen they contain in their
proteins is returned to the soil or water and the bacteria can break it down into
nitrate or nitrites, which is returned back to the atmosphere.
Ecosystem Succession
How Ecosystems Change
We have looked at energy flow in the system and cycling of materials, now we will
look at how ecosystems change. Ecosystems undergo succession which is the
regular pattern of changes over time in the types of species in a community.
The process may take hundreds or thousands of years.
The final stable community that forms if the land is left undisturbed is called the
climax community.
Primary Succession
When succession occurs in areas where no ecosystem existed before. Ex: Islands
created by volcanic eruptions and areas exposed when a glacier retreats. Primary
succession is slower because it begins where there is no soil.
pioneer species = the first species of plant, animal or decomposer to inhabit a
piece of land, water etc
these species are joined by other organisms and then these organisms are replaced
with other species as the community becomes more mature.
Secondary Succession
- occurs where an ecosystem previously existed.
i.e. areas burned by fire that have re-grown, farmland that has been abandoned
being used for farms again
Fresh Water Pollution
A pollutant is a waste material that pollutes air, water or soil.
There are two types of pollutants:
Point Pollution: pollution that is discharged from a single source such as a
factory.
Nonpoint Pollution: pollution that comes from many sources rather than a
single source such as homes, lawns, farms etc.
Water pollution is the introduction of a chemical, physical or biological material
into water that degrades the quality of the water and affects the organisms that
drink it and live in it.
Two causes: industrialization and human population explosion.
Air Pollution
Air Pollution: the air contains substances that are harmful to living things. These
can come from smoke or other harmful gases Ex: oxides of carbon, nitrogen and
sulfur
Two Types of Air Pollutants: Primary and Secondary
Primary Pollutant: a pollutant that is put directly into the atmposphere by human
activity Ex: soot from smoke, exhaust from cars.
Secondary Pollutant: a pollutant that forms when a primary pollutant or a
naturally occurring substance such as water comes into contact with other primary
pollutants and a chemical reaction takes place.
Ex: ozone production
Major Air Pollutants
Carbon Dioxide: produced by incomplete burning of fossil fuels. Sources:
vehicles and industrial processes. Harmful effects: interfers with oxygen transport
in the blood causing drowsiness, headaches and death.
Nitrogen Oxides (NOx): nitrogen and oxygen combine when combustion
temperatures exceed 5380C. Sources include: vehicles and power plants. Harmful
effects:respiratory infections, lung diseases, cancer.
Sulfur Dioxide (SO2): produced by reactions between sulfur and oxygen.
Sources: burning fossil fuels (smelters, paper mills). Harmful Effects: acid
rain, harm plant life, irritate respiratory systems.
Volatile Organic Compounds (VOC): organic chemicals that vaporate into
toxic fumes (gasoline). Sources:burning fuels from solvents, cars. Harmful Effects:
smog, cancer, harm plants.
Particulates: Smoke, ash etc from burning fuels. Sources: industrial
processes, vehicles, burning wood. Harmful Effects:produce clouds that
reduce visibility, cancer.
Greenhouse Effect
Natural warming makes the Earth livable
Natural gases in our atmosphere act like a blanket or a glass in a greenhouse- they
keep the surface of the Earth warm.
Increases in gases i.e. CO2 from human activity add to the natural Greenhouse
Effect and trap more heat than we need this results in global warming.
The blanket surrounding the earth becomes larger and more heat is traped,
increasing temperatures on Earth.
Major Greenhouse Gases
CO2 - carbon dioxide - emitted when fossil fuels are burned in cars, factories and
powerplants.
CFC's - used in making some plastics, foam insulation, and electric equipment, it
is in car air conditioners, fridges and spray cans.
methane - the main source is from cows and livestock
nitrous oxide - produced naturally, but humans have increased it by using
chemical fertilizers
ozone - car exaust and coal burning plants
What is Global Warming/Climate Change?
Global Warming = an increase in the earth's average atmospheric temperature that
causes corresponding changes in climate and that may result from the greenhouse
effect
Climate Change = any long-term significant change in the weather patterns of an
area
= can be natural or caused by changes people have made to the
land or
atmosphere.
Ozone Layer
The stratosphere contains the Earth's ozone layer.
Ozone is formed by three oxygen atoms and it absorbs most of the UV light
from the Sun.
It acts like a sunscreen to protect the Earth from damaging UV rays.
Chlorofluorocarbons (CFCs)
CFCs were believed to be miracle chemicals used in coolants, Styrofoam
making and in everyday products like hair spray.
CFC molecules can be broken apart high in the stratosphere where UV
radiation is absorbed. When CFCs go up into the atmosphere, the
chlorine atoms destroy ozone. Each CFC molecule has 4 chlorines and
each chlorine can destroy 100,000 ozone molecules.