S
Science 1206
Life Science – Sustainability of Ecosystems
Exploits Valley High
Version 1.0
Unit 1 – Life Science
Sustainability of Ecosystems
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Define sustainability
Examine historical attitudes and practices in relation to those of sustainability.
Define a paradigm and paradigm shift.
Discuss how attitudes towards pesticides have changed
Discuss how attitudes towards forests have changed with respect to commercial
usage, residential usage and replanting programs.
Define ecology and ecosystem.
Explain how biotic and abiotic factors affect ecological interactions.
Define abiotic factors (include space, temperature, oxygen, light, water, inorganic
and organic soil nutrients)
Define biotic factors (include decomposing animals, disease, predator/prey,
competition, symbiosis).
Define succession.
Describe the factors that contribute to succession.
Describe what is meant by the term climax community.
Examine the flow of energy in ecosystems using the concept of pyramid of
energy.
Examine how energy availability affects the total mass of organisms in
ecosystems and summarize this relationship in a pyramid of biomass.
Define niche and relate it to habitat.
Classify organisms as producer, consumer, autotroph, heterotroph, decomposer,
herbivore, carnivore, omnivore, and saprobe.
Define competition and explain how competition arises among organisms.
Differentiate between interspecific and intraspecific competition.
Describe the feeding relationships in terms of competition, food chains, and food
webs.
Demonstrate how the many interrelated food chains give a community its stability
and identify the conditions required for a stable self sustaining ecosystem.
Examine the use of pesticides over the course of human history.
Describe the impact that DDT usage has had on bird populations
Describe how continued DDT usage in third world countries is impacting bird
populations
Diagram the carbon cycle and describe the processes required to cycle from
carbon reservoirs to the atmosphere.
Describe the importance of oxygen to ecosystems.
Describe the significance of global warming and eutrophication.
Describe how humans have altered the C, O, and N cycles in ecosystems.
Describe what is being done to negate human impact on these cycles
Analyze the impact of external factors on the ecosystem biomes; include weather
change, introduced species, pollution and industry/agriculture.
Explain why ecosystems may respond differently to short-term stress and longterm change
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Describe the potential impact that a large scale logging project could have on a
native species such as the pine martin
Explain the impact that an abnormally dry summer could have on a bog
ecosystem
Describe how ecosystems are able to respond to changes and return to its previous
state
Describe how soil composition and fertility can be altered and how these changes
could affect an ecosystem.
Explain the role that fertilizers and irrigation practices have had on soil quality
Describe the potential impact that overuse of fertilizers can have on ecosystems
Relate the distribution of biomes within Canada to the impact of external factors.
discuss how abiotic factors affect the distribution of organisms
discuss the reasons for ecosystems that share similar abiotic features also sharing
similar animal life.
Describe how Canadian research projects in environmental science and
technology are funded.
Compare the risks and benefits to the biosphere of applying new scientific
knowledge and technology to industrial processes
Propose and defend a course of action on a multi-perspective social issue.
Describe the role peer review has in the development of scientific Knowledge.
Identify examples where scientific understanding about an ecosystem was
enhanced or revised as a result of human invention or related technologies.
Discuss the improvements that have occurred with respect to pest control.
Define sustainability
 Sustainable development – the development of our resources to meet both the
current demands and the long-term demands of the resource; the practice of
managing a resource in such a way that it will meet the needs of the present
without jeopardizing the needs of future generations.
 Discuss historical attitudes and practices in the fishing industry, the forestry, the
moose population and other resources in relation to sustainability.
 Read the Lorax by Dr. Seuss (Appendix A).
 Complete activity: A Sustainable Resource (Appendix A).
Define a paradigm and paradigm shift.
 Paradigm – A generally accepted viewpoint or way of thinking. The way that
humans view the world is known as a paradigm. "The earth and all things on it
exist for the sole benefit of humans" was an old world paradigm.
 Paradigm Shift – when how everyone views something suddenly changes; refers
to a change in view with respect to a generally held belief. Changes in paradigms
are known as paradigm shifts.
 Examples:
 Cod fishery (endless supply of cod vs. limited numbers)
 Endless supply of wood on NL (vs. forests are limited)
 Spontaneous generation (vs. biogenesis)
 World is flat (vs. sphere)
 Earth the center of the universe (vs. the sun)
 Models of the atom
 The Earth's resources are not in endless supply for our plunder.
J.E. Lovelock, a British scientist, compares the earth to a living body. Our planet is a
living, self-regulating system; (in terms of climate and chemical composition).
The earth must be in a state of balance or equilibrium with every other component. What
affects one part affects all parts.
Paradigm shift to come from the 1992 World Summit in Rio:
 The world must cut their emissions of green house gases to 5% below the
1990 level.
 We have the power to influence all life on this planet. With this power comes
an equal responsibility for stewardship.
 We must recognize that we share this planet with many other creatures and
that we are willing to balance our needs with those of other species
Kyoto accord:
 Attempt to reduce the greenhouse gas emissions 5% below 1990 levels.
 Each country would be given so many credits. If they used up all their credits,
they would have to pay a fine or fee.
Comment on the statement – Canada should (should not) ratify the Kyoto accord
Examine historical attitudes and practices in relation to those of
sustainability.
Changes in our paradigms about our forests:
If trees were cut down to build a ship, a home, or to use as fuel, little or no thought was
given to it. The forests extended as far as the eye could see, and beyond. The forest would
simply grow new trees to replace those taken. People would never have to worry about
having enough trees for their use. The early foresters used simple tools including an axe
and a saw. A typical forest worker could cut and stack about two cords (a cord is defined
as a pile of wood 4 feet high x 4 feet wide x 8 feet long) of wood per day. Today,
technology has changed and the equipment is available which can cut 2 cords of wood in
just a few minutes rather than a day. With this change in technology, can our forests now
be considered limitless? What will happen to our forests if we cut them down at a rate
faster than they can grow back? What effect does clear-cutting have on the forest
ecosystem?
Changes in our paradigms about our fishery:
Fish would be taken from the seas with no thought about the number that remained. It
was believed that man could never take all the fish that existed within the lakes and
oceans because there were so many fish and relatively so few fisherman. The technology
used by the inshore fisherman included the use of an open boat known as a dory and a
single jigger (large hook with an attached lead weight fashioned like a fish) attached to a
length of line. The jigger was thrown over the side of the boat and allowed to sink to the
bottom. The jigger would then be brought up just off the bottom and jigged up and down
until it struck a cod. The cod was then hauled to the surface and thrown into the boat at
the fisherman's feet. This cycle was repeated until the boat was full.
Modern technology has changed to include the use of factory ships which make use of
drift nets more than 5 km long, and electronic equipment designed to detect the location
of the fish. As a result of modern technology, fish are caught by the metric ton rather than
as individual fish. The number of fish taken as a result of the use of modern technology
has destroyed the fish stocks to the point that the Atlantic Canada fishery has been shut
down to allow the recovery of the fish stocks. Was the change in fishing technology
sustainable? Can we manage a sustainable fishery in the future?
Discuss how attitudes towards pesticides have changed.
Use of pesticides over the course of human history
 First-Generation Pesticides
o As early as the 500BC sulfur was first used to repel insects
o During the 15th century arsenic, lead and mercury were applied to crops as
insecticides
o In 1763 French gardeners began using nicotine sulfate, a chemical extracted
from the tobacco plant, to kill insect
o By the mid 1800’s two more plant extracts were being used: Head of the
chrysanthemum and the Root of a tropical legume
o Many plants have developed chemical defenses against animals
 Second-Generation Pesticides
o Chemical made in the lab
o In 1939 Paul Mueller created DDT
o Over 500 chemical pesticides are registered for use in Canada alone
o 2.3 million tons of pesticides are used every year  0.4 kg for every person
Chemicals taken from plants create a much lower risk for humans and the ecosystem
Many people now consider pesticides themselves to be a problem and many provincial
and municipal governments have banned their usage in many locations. The town of
GFW has now banned the sale of these products in local stores and their usage must be
regulated by certified lawn care specialists. This is a major paradigm shift in this field.
Farmers use of pesticides:
 30% of the annual crop in Canada is lost due to pests
 Cost
 In 1954 three million tones of wheat from the Prairies was destroyed by stem rust
Homeowners may use pesticides:
 To grow nice/productive gardens
 Control lawn and reduce unwanted weeds/pest
Discuss how attitudes towards forests have changed with respect to
commercial usage, residential usage and replanting programs.
Many individuals and companies now understand the proper need for a sustainability
program for the forestry. This has led to reductions in the amount of wood that can be cut
for residential purposes and has seen major changes in the industry related to cutting
practices, replanting and other issues related to silviculture.
Forestry companies use pesticides on huge tracks of forest land
 Spruce budworm
 From 1986 to 1990 NB dispensed about 170,000 kg of chemicals over 443,000 ha
every year to control the growth of budworms
People are concerned about spraying pesticides close to communities and in the
watershed that provides communities with drinking water.
 Public ideas about chemicals
 Unknown effects of chemicals
Define ecology and ecosystem
Ecology - The study of the interactions among living organisms and between organisms
and their non-living environment. (Oikos – the place where one lives; logos – the study
of).
Ecosystem - An area, which includes the relationships between populations of species
and between those populations and the non-living (abiotic) factors in their environment.
An Ecosystem is a community of organisms and the physical environment in which it
lives.
Ecosystems are dynamic (always changing) and change be either natural or artificial
(man-made). The area between and connecting 2 or more ecosystems is called an ecotone
(the grassy meadow found between a pond and a forest).
Population - All of the members of the same species in an ecosystem or habitat.
Community - The collection of all the populations of species in the ecosystem.
Define abiotic factors
Abiotic factors are nonliving factors (were never alive) in an ecosystem.
Abiotic factors:
 Temperature (Environmental temperature affects biological processes and
the ability of most organisms to regulate their temperature. Few organisms
have active metabolisms at temperatures below 0oC or above 45oC
because enzymes function best within a short range of temperature and
become denatured if the temperature is too high).
 Amount of sunlight (Sunlight is the ultimate source of energy for all
photosynthetic organisms which in turn provide the resources for other
living things (in most ecosystems). Light also affects the development and
behaviour of many organisms).
 Strength and direction of wind
 Soil (inorganic and organic soil nutrients) Inorganic soil nutrients include
minerals such as phosphates, nitrates, potassium, magnesium and a host of
other minerals derived from rocks. Organic nutrients include organic
compounds in humus which promote the growth of bacteria, fungi, and a
host of other organisms beneficial to the soil. The physical structure, water
holding potential, pH, and nutrient level of soil limit the distribution of
plants and in turn the animals that inhabit a terrestrial region.
 Space (All organisms require enough space or territory to insure adequate
resources to food, water, shelter, and mates).
 Oxygen (Most living organisms require oxygen for cellular respiration,
which is a process that releases energy from food).
 Water (Water (humidity) is necessary for all life. The ability to find water,
to maintain water balance, and to conserve water help determine the
habitat range for each species).
Define biotic factors
Biotic factors are the living factors/components found with an ecosystem. It includes any
once-living factors. Biotic factors include all other organisms that interact with the
individual both of the same species and all other species.
 Predator-prey relationships (important biotic factor which helps to limit
the size of populations within an ecosystem. A predator is an animal that
kills and eats another animal for food. The prey is the hunted animal. An
example is the lion and the zebra. When a lion kills a zebra for food, the
lion helps to prevent the overpopulation of the zebra. If the number of
zebra declines too much the lion will starve. There is a balance between
the number of predator and prey in any ecosystem.
 Food chains/webs
 Disease (bacteria, etc.) Disease is the result of infection by fungi, bacteria,
virus, and other pathogens. Disease is an important biotic factor because
disease tends to reduce the number of organisms within the community.
 Competition (struggle for survival that occurs between two organisms
either of the same or different species. Competition tends to limit the size
of the population keeping it in balance with the available resources.)
 Decomposition (animals and plants (detritus)). Detritus refers to
decomposing plant and animal materials including their dead bodies as
well as their wastes. Bacteria and fungi living in the ecosystem help to
break down the materials within the detritus and recycle these materials
back to the plants.
 Symbiosis (biotic relationships in which two different organisms live in
close association with each other to the benefit of at least one).
Symbiotic relationship: A relationship in which two different organisms
live in a close association.
Types of symbiosis:
a) Parasitism – one organism benefits (parasite) and the other is
harmed (host). E.g. Tapeworm
b) Commensalism – one organism benefits but the other is not
harmed. E.g. Beaver and fish, Tree and nesting bird.
c) Mutualism – both organisms benefit.
E.g. fungus provides the algae with carbon dioxide and
water for photosynthesis and the algae provides food to the
fungus
d) Parisitoidsm –One organism benefits the other is eventually
killed.
E.g. Wasp stings a spider causing paralysis. The wasp then
lays a single egg, which hatches into a larva and eats the
body of the spider.
e) Predation –where the interaction is good for one species and
detrimental to the other. E.g Bear and caribou.
Explain how these factors affect ecological interactions.
Perform a lab activity to investigate how abiotic factors of wind, temperature and
light affect the distribution of plants (page 24 in text – schoolyard ecosystem or
log lab).
Define succession and describe what is meant by the term climax
community.
Ecological succession refers to the series of ecological changes that every community
undergoes over long periods of time. It is mainly the gradual change from one plant
community to another. The process of succession begins with relatively few pioneering
plants and the animals that are associated with these plants. The plant life serves as food,
and often shelter for the animal life that can survive in that environment. The succession
in the plant life is therefore paralleled by a succession in animal life. As a result of the
process of succession, a primitive community develops.
The organisms that make up the primitive community gradually change the
environmental conditions so each successive community paves the way for the next. Each
successive community develops through increasing complexity until it becomes a final,
sustainable, stable, or self-perpetuating community, of dominant organisms, known as a
climax community. In an ecosystem with a climax community, the conditions continue to
be suitable for all the members of the community. The climax community is the final
stage of ecological succession.
Two types of succession:
Primary succession refers to a sequence beginning in an area where there is no soil or
previous forms of life. Primary succession occurs in an area such as a freshly cooled lava
field, or a newly formed sand dune. In terrestrial habitats, primary succession is a very
slow process because it begins with the formation of soil. The soil forms as a result of
weathering and the action of pioneer organisms. Large rocks are broken down into
smaller pieces and eventually bacteria, fungi, and lichens inhabit the area. These
organisms are known as pioneer organisms because they are the first type of life to
inhabit the region.
The pioneer organisms add organic matter to the primitive soil, changing the conditions
of the microenvironment so that mosses, ferns, and other primitive plants begin to take
over. Grasses may eventually replace the more primitive plants and when they die, they
make the soil even richer. Shrubs grow and shade the grass causing it to die. Then trees
may grow and shade out the shrubs. Seedlings of other trees may grow well in the shade.
In this way, one community of trees will be succeeded by another community with
different trees. This process of succession will continue until a dominant or climax
community is finally established.
Secondary succession occurs in an area in which an existing community has been
partially destroyed and its balance upset, either by natural causes, such as fire, or as a
result of human activity, such as the cutting of a forest, or abandoning a farm.
The major difference between primary and secondary succession in a terrestrial
environment is that in secondary succession, soil already exists. Seeds of plants will
begin to grow. Those that do grow will come from dormant seed already in the soil, or
will come from plants in communities nearby. The seeds will establish a community but
succession will eventually result in a climax community that is often the same as would
normally be found in the typical climax community in the region. An abandoned farm
may become a forest given enough time.
The final climax community is generally the same as the climax community that
surrounds the disturbed area. The series of stages leading to the climax community will
not be the same as for a primary succession that created the original climax community.
Describe the factors that contribute to succession.
The type of climax community that is established will depend on the environmental
conditions of the area. The most important environmental conditions that affect
succession include:
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climate (temperature, precipitation, and availability of sunlight),
soil (salinity, fertility, moisture, texture, etc.),
geographical features (latitude, altitude, and proximity to mountain ranges or
large bodies of water).
For example, in a hot arid desert, the climax community will certainly be quite different
from the climax community that would form in a humid but cool environment such as a
boreal forest (Taiga).
Some biologists argue that there is no such thing as a climax community because the
entire earth is in constant change or upset. The causes of upset include:
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natural (catastrophic events such as flood, fire, volcanic activity, climate change,
species extinction, etc.),
and human influenced (such as acid rain, ozone depletion, enhanced global
warming, pollution, habitat destruction, monoculture farming, clear-cut logging,
over-fishing, etc.).
Every ecosystem exists because there is a balance between its members (producers,
herbivores, omnivores, predators, scavengers, parasites, competitors, decomposers, etc.)
and its abiotic environment (climate, soil, availability of sunlight, pH, oxygen levels,
salinity, etc.). It is this balance between the biotic and abiotic factors that creates the
stability of the ecosystem.
In general, the greater the biodiversity, the greater the stability. In spite of this stability,
every ecosystem is also relatively fragile in that the entire ecosystem may be stressed or
even destroyed. Any factor or group of factors that upsets the balance that maintains
stability must be of concern to all humankind. Humankind must be aware that what we do
as a species will ultimately affect the spaceship Earth.
Define niche and relate it to habitat.
Niche, refers to the role that a species plays within its ecosystem. In balanced
ecosystems, each species occupies its own niche. The niche is like the organism's
profession - what it does to survive.
 Each organism has its own place within an ecosystem
 The organism’s place in the food web, its habitat, breeding area, and the time
of day that it is most active is its ecological niche
 The niche an organism fills in an ecosystem includes everything it does to
survive and reproduce
 Each organism in an ecosystem tends to have a different niche. This helps
reduce competition between species for the same resources and territory
 Example: Owl and hawk feed on the same organism but they occupy distinctly
different niches. See page 41, figure 2 - warbler
Habitat – refers to the place were an organism lives. The habitat of a species is different
than its niche, it is the particular part of the environment in which it lives. The habitat of
an organism is part of its niche. The organism's habitat is its address - where it lives.
Classify organisms as producer, consumer, autotroph, heterotroph,
decomposer, herbivore, carnivore, omnivore, and saprobe.
 The source of all the energy found in ecosystems is the sun.
 Plants use the suns energy to make carbohydrates (sugars) through a process
called photosynthesis
 The levels of a food chain are called trophic (feeding) levels. Trophic structure
refers to the feeding relationships within the ecosystem. These feeding
relationships are generally divided into five trophic levels based on their source of
nutrition and include primary producers, primary consumers, secondary
consumers, tertiary consumers, and decomposers (also known as detritivores).
Feeding relationships are generally viewed as a food web consisting of all the
possible food chains that exist within the ecosystem.
 Autotrophs or producers - Organisms that can make their own food; these are
located in the first trophic level; an organism that uses photosynthesis or another
form of chemical synthesis to make food. Ex: plants, algae and some types of
bacteria
 Heterotrophs or consumers - Organisms that cannot make their own food; obtain
nutrients from other organisms. They eat other living things. There are several
groups of heterotrophs: herbivores, carnivores, omnivores and saprobes.
 Primary consumers – Organisms that feed on the producers, located in the second
trophic level. (Herbivores – eat only plants)
 Secondary consumers – Located in the third trophic level and feed on the
organism in the second trophic level (carnivores – eat only meat, or omnivores –
eat plant and meat)
 Tertiary consumer - top carnivore; an organism that relies on the secondary
consumers for its principal source of energy; organisms at the fourth tropic level
Other roles animals/organisms could play are:
 Detritus – waste from plants and animals, including their dead remains
 Scavengers - clean-up dead carcasses
 Saprobe – also called decomposers; breaks down dead plants and animals (bacteria
and fungi); get nutrients by breaking down the remains of dead plants and animals, or
their wastes. Their main role is to recycle nutrients in dead organisms and their
wastes. Without the decomposers to recycle nutrients, there could be no life since
plants would run out of nutrients.
 Decomposers - microorganisms that complete final breakdown of organic matter; an
organism that feeds on detritus, in the process releasing nutrients to the soil and
water, where they can be used by other organisms
The importance of decomposers in an ecosystem:
 Break down detritus to get nutrients for their own use
 In the process, nutrients are released to the soil and water
 Plants and algae use those nutrients to grow
Define competition and explain how competition arises among organisms.
Competition: the struggle for survival that occurs between two organisms.
Ex. habitat, food, water, space, etc.
Competition arises because:
 Climate changes and the pressure of competition from other species force
organisms to adapt or die
 A species that is better at finding food, reproducing or defending its territory
could force competing species into extinction
 If one species disappears, it can affect other species that rely on it for food
Differentiate between interspecific and intraspecific competition.
Two types of competition:
1. Interspecific Competition – Involves competition among similar species for a
limited resource, (eg. Food or space). Example: mouse and vole
2. Intraspecific competition – involves competition within an ecological niche
between members of the same species
Describe the feeding relationships in terms of competition, food chains,
and food webs.
 Every organism provides energy for another organism. To show who eats whom we
use food chains.
Food chains
 show a step-by-step sequence of who eats whom in an ecosystem
 Ex: phytoplankton – small fish – cod – humans
 Each level in the food chain is called a trophic level.
Trophic level
 Functional classification of organisms according to feeding relationships
 In this case humans are at the top of the food chain and are referred to as the Tertiary
consumer (top carnivore)
 To show all the feeding relationships in an ecosystem we can use a food web.
 Food web:
Demonstrate how the many interrelated food chains give a community its
stability and identify the conditions required for a stable self sustaining
ecosystem.
Stability means that there is an ecological balance between the various organisms that
make up the food web, and because of this balance the ecosystem is self-sustaining over
long periods of time. To be stable there must be a balance between food production, food
consumption, and decomposition of dead organisms and/or their wastes.
This means that a stable ecosystem must have a source of energy (usually sunlight for
photosynthesis), producers to capture the sunlight and make food, and a means to recycle
the materials. The greater the biodiversity in the ecosystem the more stable it will be.
The many interrelated food chains of an ecosystem give a community stability because
every food level helps to control the numbers of organisms in the level below it. For
example, predators such as lions help to ensure the health of the zebras. Some biologists
have even remarked that the predator is the prey's best friend. The decomposers recycle
the nutrients back to the plants. In turn, the plants grow to supply the food for the
herbivores.
Examine the flow of energy in ecosystems using the concept of pyramid of
energy.
 Not all of the chemical energy that a plant creates can reach the animals that
eat it. The plant uses most of that energy to stay alive and to manufacture the
chemicals it needs to grow
 Once an animal takes chemical energy from a plant, it doesn’t store it all
 Most of the energy is used to:
o Move its limbs
o Pump blood
o Keep its body warm
o Manufacture the chemicals it needs to carry out its own life processes
 The further up the chain you travel, the less energy is available. As the food is
passed through the food web, most of the energy is lost. In general terms,
about 10% of the energy stored in one trophic level is actually transferred to
the next trophic level. This is known as the pyramid of energy. Eventually
there is so little energy remaining in the top trophic level that no higher
trophic level can be supported. This is why there are so few if any fourth order
consumers in an ecosystem.
Pyramid of Energy
 Measures the amount of energy available at each trophic level
 The larger the volume of each level, the greater the energy at that level
 Energy is measured in joules
 Why does the data produce a pyramid:
o The primary producers use light energy to manufacture food which is utilized
by all other trophic levels for all life activities such as growth, maintenance,
and reproduction, and in many cases, locomotion. The ecosystems entire
energy budget is determined by the photosynthetic activity of the primary
producers.
o In general, 10% of all the energy in a trophic level gets passed on to the next
level. This generalization suggests that 90% of the energy taken in at any
trophic level is lost during the life of the organisms to carry on its own life
processes and is lost as heat. Only 10% of the energy is therefore able to be
transferred from one trophic level to the next.
o Thus, the amount of life that can be sustained at each level, going to the top,
decreases. This is why we cannot have more than five levels in a food chain.
Example: If the corn plants in a given area of a corn field fix 10,000 J of energy, only
1,000 J will be available to be passed on to the mouse, 100 J would be passed on to the
snake, and only 10 J would be passed on to the hawk. The idea that each higher trophic
level has less energy available to it is known as the pyramid of energy.
Examine how energy availability affects the total mass of organisms in
ecosystems and summarize this relationship in a pyramid of biomass.
Pyramid of Biomass
 Measures the dry mass of the tissue in plants and animals; the dry mass is
known as biomass.
 Because the amount of energy at each level is 90% less than in the one in under it,
the number of organisms support at each level decreases.
 The pyramid of biomass is a graphical representation of the total biomass of all
the members of each trophic level. Generally the pyramid of biomass has the
same shape as the pyramid of energy. There is a large base representing the total
biomass of the producers with each higher trophic level having a progressively
smaller size, representing the progressively smaller amount of biomass present. In
a grassland environment, 10,000 kg of grass and other producers (dry mass)
should support about 1,000 kg (dry mass) of grasshopper and other plant eating
insects.
Pyramid of Numbers
 Measures the number of organisms at each trophic level.
 It shows the decrease in numbers of organisms as you move through trophic
levels of a food chain.
 The pyramid of number is often similar in shape to the pyramid of energy or
biomass, but there are exceptions (eg a tree) because of the physical size of the
members of a food chain
Examine the use of pesticides over the course of human history.
Pests are living organisms that are not wanted around us. Examples include unwanted
dandelions growing in the lawn; rodents or insects that eat fruits, vegetables or other crop
species; micro-organisms that cause disease in forest, fish, or crop resources, etc. A pest
is any organism that man believes is undesirable, has a negative impact on the human
environment, or is in competition with human use of a resource, either natural, or
cultivated.
Pesticides are chemicals designed to kill pests, organisms that people consider harmful or
inconvenient
Early Pesticide Use:
Early pesticides included the use of toxic inorganic metallic salts such as copper sulfate,
lead salts, arsenic, or mercury. These substances were generally effective against the
intended pest, but also created some environmental problems because they also killed
other beneficial organisms, and polluted water and soil resources used by man. Most
early pesticides were non-biodegradable (meaning that they were not broken down within
the ecosystem). As a result, these early pesticides began to accumulate in the
environment, contaminating water and soil resources, eventually poisoning humans.
Modern Pesticides:
By the twentieth century, chemists began to develop organic pesticides that were
designed to be less toxic to man and more specific toward the intended pests. Although
this was initially believed to be a step in the right direction, man soon discovered that the
organic pesticides also caused unexpected environmental effects. Some of these
pesticides were fat soluble. This characteristic lead to a problem known as
bioaccumulation.
Four types of pesticides
Type of Pesticide
Insecticide
Target
Insects
Example
DDT
Malathion
Herbicide
weeds
Fungicide
Moulds and other
fungi
Bacteria
2,4-D, Silvex,
Roundup
Captan
Persistence
High (2-15 years)
Moderate (1-12
weeks)
Mostly low (days to
weeks)
Low(days)
Penicillin
Mostly low
bactericides
Describe the impact that DDT usage has had on bird populations.
Because of bioaccumulation, as each organism feeds on one lower in the food chain, the
fat soluble pesticide began to be concentrated in ever higher amounts as one moved
toward the top of the food pyramid. Since every organism eats far more than its own
body mass in food, the tiny amounts found in each organism in the lower levels of the
food web began to accumulate in greater concentrations in species located at higher
trophic levels.
 Pesticides that contain chlorine, such as DDT, are soluble in fat but not in water
 As a result, they cannot be released in urine or sweat and accumulate in the fatty
tissues of animals
 Small amounts of chemicals enter the food chain at the lowest levels.
 The problems gets worst as the toxin moves up the food chain.
 At each stage of the food chain the concentration of toxin get higher
 The higher the trophic level, the greater the concentration of toxins
 This process is referred to as bioamplification
One example of this problem is illustrated by the damage done to predatory birds as a
result of bioaccumulation of DDT. As a result of this problem DDT has been banned
from use in North America.
Describe how continued DDT usage in third world countries is impacting
bird population.
Because DDT is a very effective pesticide that is readily available and cheap, it is still
used in many of the poor countries of the world. Due to the migratory nature of many
bird and fish species, this continues to create problems in many parts of the world.
Read 2.2 "Case Study: Pesticides" on pages 52 - 57. Answer questions 1 - 10 from
"Understanding Concepts," "Making Connections," and "Reflecting" on page 58.
Discuss the improvements that have occurred with respect to pest control.
IPM stands for Integrated Pest Management, a sustainable approach that combines the
use of prevention, avoidance, monitoring and suppression (PAMS) strategies in a way
that minimizes economic, health, and environmental risks.
Integrated pest management combines several approaches to the management of pests.
Two of these management control approaches are chemical control and biological
control.
Chemical control:
 Chemical control makes use of chemical pesticides in the control of insect pests.
 Problems: biomagnification or bioamplification during which concentrations of
pesticides accumulate in higher concentrations at higher trophic levels of the food
web.
 Pesticide resistance: Use of chemical pesticides kills most but not all of the pest
population, leaving those pests which are resistant to reproduce a new population
of chemical resistant pests..
 A third problem is related to the lack of specificity which means that the chemical
pesticide tends to kill beneficial organisms as well as the pest organism targeted.
This upsets the natural balance in the food web due to the death of many natural
predators.
Biological Control:
 Biological control makes use of natural predators, disease organisms, or
competitors to reduce the size of the pest population to a level that significantly
reduces their impact on the resource being protected.
 Trichogramma minutum is a tiny parasitic wasp that has been used in forest
management of spruce budworm in Ontario. The female wasp parasitizes the eggs
of the spruce budworm. It prevents the spruce budworm eggs from developing
into the larval stage.
 Winthemia occidentis:. This tiny fly lays its eggs on the pupa of the hemlock
looper. Once the fly eggs hatch, they begin to feed on the looper caterpillar. the
looper caterpillar dies as a result, but the parasitic adult fly soon emerges to infect
other looper caterpillars.
 Bacillus thuringiensis (B.T.): has been used in the management of forest insects
(mainly against spruce budworm and hemlock looper) in Newfoundland. The
bacteria are sprayed on the forest needles and picked up by the insect pest. Once
inside the digestive system of the insect, the bacterium acts like a disease
organism and kills the insect pest.
 Disadvantages to the use of B.t.
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the bacteria are washed off the needles of the tree by rain.
they become less effective after a few days exposure to sunlight, so B.t.
only works for a short period of time.
the production of the bacteria tends to be expensive.
 Pheromones are chemical "perfumes" produced by the female to attract a mate.
Pheromones have been used as a biological control technique both in forestry and
agriculture. Biochemists have isolated pheromone compounds and have been able
to manufacture them in the lab. The synthetic pheromones have been successfully
used in the biological control of some insect pests. One method of control
involves using the pheromone to attract insect pests to a trap. The trap contains a
sticky glue which prevents the escape of the insect. It is also possible to use the
pheromone to upset mating. This is accomplished by spraying the synthetic
pheromone within the forest ecosystem. The male insect detects the pheromone
from all directions so the male is unable to locate the female thereby preventing
mating.
Diagram the carbon cycle and describe the processes required to cycle
from carbon reservoirs to the atmosphere.
Although organisms are different in terms of the relative amounts of each type of element
present, the types of elements are the same. Fewer than 20 elements are presently known
to occur in the tissues of living things. Oxygen, carbon, hydrogen and nitrogen make up
the vast majority of living tissue. These elements are recycled between living organisms
and the soil, water and atmosphere of the Earth.
These elements are first taken up by plants, some oxygen is released to the atmosphere as
a product of photosynthesis, but the rest is converted into food, passed through the food
web as they pass through plants, consumers, and finally decomposers such as fungi and
bacteria, and then returned to the environment in a continuous recycling of materials. If
recycling of these materials did not occur, life could not exist.
The continuation of life depends on the continued recycling of the materials that make up
the food that passed through the ecosystem. Some of these elements (carbon, oxygen,
sulfur, nitrogen) are found in gaseous forms and their cycles involve the atmosphere. As a
result they have a global nature. One should also be aware that some of the elements may
have a short term cycle such as when carbon is transferred from animals to plants in the
form of carbon dioxide and a long term cycle such as the transfer of carbon from a fossil
fuel to a plant following combustion.
The elements are cycled between the living organisms and the environment (both long
and short term). It is a combination of biological and geological processes that drives
chemical recycling.
Biological processes include:

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respiration,
decomposition,
excretion,
photosynthesis,
and assimilation.
Geological processes involve fossilization, erosion, combustion of fossil fuels (peat, oil,
coal), weathering, and formation of sedimentary rock.
The importance of sunlight to sustainability of an ecosystem:
 It is the source of all energy for ecosystem
 It lights and warms the surface of our planet
 Gives energy needed to evaporate water from oceans and lakes
 Provides the energy for green plants to make the compounds that maintain
their lives and serve as food for all other organisms
 Figure 1, pp. 32
o 30% reflected by clouds or earth’s surface
o 44% heats atmosphere and earth’s surface
o 25% heats ad evaporates water
o 1% generate winds
o 0.023% photosynthesis
Carbon Cycle
 The matter cycle in which through the processes of photosynthesis, digestion,
cellular respiration, decomposition ad combustion, carbon atoms move from an
inorganic form in the air, water or soil to an organic form in living things and then
back to an inorganic form
 Plants extract carbon dioxide and water from their environment. They use the
energy they capture from the sun to carry on a process known as photosynthesis
which converts the atoms in the carbon dioxide and water into sugar and oxygen.
Photosynthesis
 The process by which green plants use sunlight energy to produce
carbohydrates
 Photo – means ‘light’
 Synthesis – means ‘to make’
6CO2 + 6H2O + energy (sunlight) → C6H12O6 (glucose) + 6O2
 Photosynthesis and cellular respiration are complementary processes
 The carbon that they use is repeatedly cycled through both processes
 Most of the carbon that forms living organisms is returned to the atmosphere
or water as body waste and the dead organism decays
 However, sometimes the decay process is delayed and the organic matter may
be converted into rock or fossil fuels
 These are not released until it is released by processes such as uplifting and
weathering or burning of fuels
 See Figure 1, pp. 62
 Main carbon reservoirs
 Inorganic forms:
o The Atmosphere
o The oceans
o Earth’s Crust
 Organic Forms:
o Living matter
The oxygen, released as a byproduct of photosynthesis, generally passes into the
atmosphere. The sugar (known as glucose) serves a food for all consumers in the
ecosystem. The consumers carry on a metabolic process known as cellular respiration.
During cellular respiration, oxygen is taken in from the atmosphere and used to break
down the sugar resulting in a release of energy and the molecular products, carbon
dioxide and water.
C6H12O6 + 6O2→ 6CO2 + 6H2O + energy (ATP)
As you can see from the equations, photosynthesis and cellular respiration are
complementary processes. Provided these processes occur in balance, the amount of
carbon dioxide (about 0.023% of the air) and oxygen (about 21% of the air) are
maintained in equilibrium. This balance is called the carbon-hydrogen-oxygen cycle (or
carbon cycle).
Describe the importance of oxygen to ecosystems.
Oxygen is necessary to support life in terrestrial and aquatic ecosystems.
 Most living things use oxygen to break down sugars , their source of energy
 Carbon dioxide and water are released as the sugars are broken down
 The reaction is called cellular respiration
Sugar + oxygen  carbon dioxide + water
 Any organism that requires energy will undergo some form of respiration
 Plants do undergo respiration
 However, plants produce about 9X as much oxygen by photosynthesis as they use
in cellular respiration
The Earth's atmosphere contains about 21% oxygen (by volume). Oxygen (O2) is a
byproduct of the process of photosynthesis and is used by the consumers to carry out
cellular respiration from which energy is released from the foods they eat. Oxygen is also
required by plants because they also carry out cellular respiration to release the food
stored in their cells. Oxygen is therefore necessary for life on Earth.
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




Oxygen gas (O2) is recycled as part of the carbon, hydrogen, and oxygen cycles.
Oxygen gas is cycled between the atmosphere and the living organisms of both
aquatic and terrestrial ecosystems.
Oxygen gas from the atmosphere is absorbed by the water in aquatic ecosystems.
Oxygen is also produced as a byproduct of the photosynthetic organisms that live
in the aquatic ecosystems.
Heterotrophs (consumers) living in aquatic ecosystems require oxygen for cellular
respiration but they receive their oxygen from the dissolved oxygen in the water.
Ozone Protects Life from UV Radiation. Ozone is a form of oxygen (O3) that
serves as a protective layer, filtering out the harmful UV radiation and thereby
protecting life here on Earth from the harmful effects of UV radiation. In recent
years, human activities have lead to the destruction of the ozone layer. This
environmental problem is known as ozone depletion.
The Nitrogen Cycle






The movement of nitrogen through ecosystems, the soils and the atmosphere
About 79% of the atmosphere is nitrogen
All living things need nitrogen to make proteins
Nitrogen is also required for the synthesis of DNA
However, neither plants nor animals can use nitrogen directly
See figure 1. pp. 66
Nitrogen is essential to living things for the production of amino acids used to synthesize
proteins, and nucleic acids which are used to carry the hereditary or genetic code. Life
can not occur without these compounds. Even though the atmosphere is about 79%
nitrogen gas, plants and animals are unable to use nitrogen gas directly as a source of
nitrogen to make organic nitrogen compounds. The nitrogen cycle can occur in both
terrestrial and aquatic ecosystems.
In order for plants to make use of nitrogen it must first be converted into ammonia or
nitrates. Some plants can make use of ammonium ions (NH4+) but these types of plants
are relatively rare. The vast majority of plants must obtain their nitrogen in the form of
nitrate ions (NO3-) dissolved in soil water. There are two pathways by which nitrate ions
can be produced in natural terrestrial ecosystems.


Nitrogen fixation – processes in which atmospheric or dissolved nitrogen in
converted into nitrate ions
The first is nitrogen fixation by lightning which produces nitrates directly. The
energy from the lightning causes nitrogen gas to react with oxygen in the air

producing nitrates. The nitrates dissolve in rain or surface water, enter the soil ,
and then move into plants through their roots
The second is nitrogen fixation by bacteria (producing ammonia) followed by
nitrification by bacteria (converting the ammonia to nitrates). The bacteria in the
soil ‘fix’ nitrogen by producing nitrates and making them available to plants
o These bacteria provide the vast majority of nitrates found in ecosystems
o They are found mostly in soil
o Can also be found in small lumps called nodules on the roots of legumes
(peas, beans, clover, brussel sprouts, etc.). The nitrogen fixing bacteria
found in nodules usually make more nitrates than the plant or bacteria
needs. The excess moves into the soil providing a source of nitrates for
other plants
o The bacteria provide the plant with a built-in supply of usable nitrogen and
the plant provides the bacteria with sugar (mutualism). \
When animals consume plants, the animal breaks down the plant proteins into amino
acids and then can use the amino acids to make the protein it needs
Denitrification:




The process, performed by some soil bacteria, in which nitrates are converted to
nitrites, and then to nitrogen gas
It is part of the nitrogen cycle
It does not require oxygen
It ensures the balance among soil nitrates, nitrites and atmospheric nitrogen
Describe the significance of global warming and eutrophication.
Global warming is the term given to describe the recent increase of the earth’s
temperature as a whole. The earth’s weather and climate is controlled by energy from the
sun, which warms the surface of the earth as it, in turn, deflects the energy back into
space. Some of this deflected energy is retained within the atmosphere of the earth by
greenhouse gases which prevent the energy from passing into space, thereby preserving
heat. It is this process that results in the earth having a temperature which supports life.
Global warming has occurred since the 1980's, and during this time, the seven warmest
years in global meteorological history have been recorded.
The three primary greenhouse gases which are responsible for this warming include
carbon dioxide, methane, and nitrous oxide, all of which naturally exist in the earth’s
atmosphere. These three gases are required in order for the natural process of temperature
control to occur. The problems arise when there is a surplus of these gases in the
atmosphere.
Causes of excess greenhouse gases include:



Carbon dioxide is released into the atmosphere by the combustion of solid waste,
fossil fuels, wood and wood products.
Methane emissions are a direct result of the production and transportation of coal,
natural gas, and oil. The raising of livestock, and the decomposition of organic
waste also contribute to the amount of methane emitted into the atmosphere.
Nitrous oxide emissions are a result of agricultural and industrial activities as well
as the burning of solid waste and fossil fuels.
There are also greenhouse gases which do not occur naturally, that are generated by
human activity. Examples of these gases include; chlorofluorocarbons found in
refrigeration devices, hydrofluorocarbons, and perfluorocarbons. Each varies in their heat
trapping ability and combined with those gases originally present in the atmosphere,
serve to retain a sufficiently larger amount of heat then would naturally be retained.
Effects of global warming:
 Human health. Throughout the world, the occurrence of particular diseases and
other threats to human health depend largely on the local climate. For example,
extreme temperatures can directly cause the loss of life (although it has the
greatest toll on very old and very young people), many severe diseases are only
found in warm areas, and as well warmer temperatures have been shown to
increase air and water pollution.
 Increasing temperatures may also increase the risk of infectious diseases, which
only occur in warm areas, such as malaria, dengue fever, yellow fever, and
encephalitis. These diseases which are spread by mosquitoes and other insects
could become more common if warmer temperatures allowed these insects to
inhabit places farther north.
 Water supply, Forests and Soil may also be affected.
Eutrophication:
 The evolution of a lake to a shallow lake and final to dry land
 See page 127
 Oligotrophic lakes
o Are typically deep and cold
o Nutrients levels are slow thus limiting the number of producers available
 Eutrophic Lakes
o Are generally much shallower and warmer
o Have an excellent supply of nutrients
o Have many producers
 In general, Oligotrophic lakes gradually become eutrophic
 Eutrophic lakes become increasingly shallow eventually filling in and becoming
dry land
 This process may take hundreds or even thousand of years
One of the factors that determine how many microscopic organisms live in water is the
availability of nutrients. The nutrients that have the most profound effect on the number
of microorganisms found in the water are nitrates and phosphates. Low levels of nitrates
and phosphates reduce the number of micro-organisms. The water appears clear and
sunlight can penetrate deeper supporting the production of oxygen by photosynthetic
organisms. Under these conditions, the pond or lake can support large populations of fish
and other organisms that are adapted to relatively high levels of oxygen. Such a lake in
which oxygen levels are relatively high is known as an oligotrophic lake.
Enrichment, the fertilization of a body of water, by nitrates and phosphates mainly from
agricultural lands and from untreated human or animal sewage causes the number of
micro-organisms to increase to the point that the water actually appears turbid (cloudy).
As a result of the bacteria, less light is able to penetrate the water and oxygen
concentrations tend to be reduced. Such a lake is said to be eutrophic.
Eutrophic lakes are generally shallower and warmer than oligotrophic lakes and because
there is a lower oxygen concentration in the water, they are unable to support the same
type of fish populations as found in oligotrophic lakes. Fish that tend to require relatively
high levels of dissolved oxygen, such as pike or trout, tend to die out and are replaced by
fish species, like catfish or carp, that can survive in lower levels of oxygen.
Years ago, phosphates were used in the manufacture of laundry detergents. Other sources
of phosphates and nitrates are untreated sewage from human and farm animal sources,
plant residues in waterways, and chemicals used in industrial processes. A ban on the use
of phosphates in the manufacture of laundry detergents, and better sewage treatment have
helped to solve the problem of accelerated aquatic eutrophication, but the problem has
not been completely solved.
According to the National Water Quality Inventory Report (1992), the main cause of
accelerated aquatic eutrophication is the contamination of freshwater systems by
fertilizers used in agriculture. As the human population expands, there is a greater need
for food resources. Fertilizers have enabled the same area of land to produce increased
crop yield but the same fertilizers are causing the acceleration of aquatic eutrophication
of our lakes and other freshwater systems.
Describe how humans have altered the C, O, and N cycles in ecosystems.
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By releasing carbon from organic reserves faster than would normally occur
Mining, burning fossil fuels, Burning forests
We are also increasing the amount if carbon dioxide in the inorganic
reservoir of the atmosphere by clearing away vegetation
In modern times (past 200 years) people have discovered these fossil fuel deposits and
have used them to supply our energy needs. Humans have also affected the carbon cycle
by cutting down forests. As a result of human activity, the amount of carbon dioxide is
being produced at a faster rate than nature can recycle it. As a result of this imbalance,
the amount of carbon dioxide in the atmosphere is increasing. As a result the earth is
presently undergoing an enhanced greenhouse effect in which the atmosphere is
gradually heating up. The gradual rise in temperature is predicted to have a disastrous
effect on world biomes. If the rise in temperature occurs too fast for organisms to adapt,
widespread extinction of plants and animals may be the result. Extinction events have
occurred in past history, but never the result of human influence. We are the only species
that can do something about the problems we have created.
As a result of human activities and their technology, the dynamics of most ecosystems
has been either totally destroyed or have had major components (trophic structure, energy
flow, chemical cycling disrupted. Most of the effects are local or regional (agricultural
effects on nutrient cycling, accelerated eutrophication of freshwater systems, introduction
of toxic compounds in food chains, etc), but some (acid rain, greenhouse effect, ozone
depletion, etc) are of global scale.
Human activities (introduction of exotic species, habitat destruction, etc) are altering the
distribution of species and reducing biodiversity (biodiversity crisis).
Describe what is being done to negate human impact on these cycles
Discuss issues of conservation and alternative fuels. Research the Kyoto Accord and
similar attempts to resolve issues related to global warming.
To reduce carbon dioxide emissions:
 Kyoto Accord
 Alternative power sources – cars
 Recycling programs
 Global awareness
Explain why ecosystems may respond differently to short-term stress and
long-term change
Short Term Stress and Long Term Change
Every living organism has a range of tolerance within which it can survive. The way that
a population responds to short term stress and long term change depends on the ability of
the organisms within the population to continue to meet their biological needs for
appropriate range of climatic conditions (temperature, light, moisture), food, water,
shelter, space, and opportunity for reproduction. Most organisms are capable of
withstanding a loss of one or more of these factors for a short period of time, but will die
if one or more of these biological needs is not met for a long period of time. Some
populations may become extinct as a result of long term change.
Short Term Stress:
Examples of short term stress include seasonal peaks in temperature, sudden changes in
water supply, or sudden but limited human impact.
Long Term Change:
Climate change (global warming), infestation by foreign plants and animals (exotic
species), and permanent human influence (habitat destruction, acid deposition, etc.) are
examples of long term change.
Read 4.5 "The Great Lakes" p. 140 - 142. Answer questions a - m and questions 1 - 4
from p.142
Describe how soil composition and fertility can be altered and how these
changes could affect an ecosystem.
Components of Soil:
Soil has a series of layers, each having different physical and chemical properties. In
general the texture of the soil becomes more coarse, and the amount of organic or living
material becomes reduced with greater depth.
 The uppermost layer is known as topsoil and consists of fine textured mineral
particles (sand, clay, etc.) and organic material (decaying plant and animal
material) known as humus. This is the layer in which plants grow. Litter is found
on top of this layer.
 Below the topsoil is the subsoil. In general the subsoil is more coarse in texture
and has less organic material. The number of organisms living in the subsoil is
generally reduced. Plant roots often invade the subsoil to gather water and mineral
resources stored in this layer.
 Below these two layers is the bedrock, which is not considered a soil layer, but
the support for the soil layers above.
Factors which affect the ability of soil to support plant life are a major concern in both
forestry and agricultural industries. These factors include:
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soil fertility,
water storing capacity,
soil pH,
salinity,
porosity to air (oxygen, nitrogen, and carbon dioxide).
Farming practice, including the use of fertilizers, pesticides, tilling and plowing of soil,
irrigation practice, and harvesting technologies all influence the soil as a living
community. One of the more important questions to consider is whether or not soil use in
forestry and agricultural industries can be maintained as a sustainable resource.
Explain the role that fertilizers and irrigation practices have had on soil
quality
 Fertilizer: Materials used to restore nutrients and increase production from land
 The numbers on a bag of fertilizer indicate the percent of each of the major
nutrients by percent. Informs the user as to how much nitrogen, phosphorus and
potassium are contained in the bag. Example: 15-52-15 contains 15% nitrogen,
52% phosphorus and 15 % potassium.
 This can be used by the consumer to reduce the negative effects of adding to
much nitrogen and phosphate to the soil
 Perform an experiment to investigate the amount of nutrients in different soil
samples (Core lab - modified)
Describe the potential impact that overuse of fertilizers can have on
ecosystems
 Farmers use fertilizers on their fields because some estimates suggest that
fertilizers containing nitrates and phosphates can as much as double yields of
crops. However, they must be used responsibility; more is not necessarily better
 Farmers should be careful to use a fertilizer with the correct ratio of nutrients and
not to overuse fertilizers. Normally, soil bacteria convert nitrogen content of
fertilizers into nitrates. However, high levels of nitrates may result in an increase
in the amount of nitric acids in the soil. This changes the pH of the soil. Changes
in the levels of acidity can affect all organisms living in the soil, including
decomposer bacteria
 Example: the annual application of 6-9 kg/ha of nitrogen fertilizer can in 10 years
produce a soil that is 10X more acidic
 This will have devastating effect on crop production
Analyze the impact of external factors on the ecosystem biomes; include
weather change, introduced species, pollution and industry/agriculture.
Relate the distribution of biomes within Canada to the impact of external
factors. Discuss how abiotic factors affect the distribution of organisms
Biome
 A biome is defined as a large geographical region that has a particular type of
climax community; A collection of ecosystems that are similar or related to each
other. Usually, based on the types pf plants they support
 A biome is a distinct ecological community of plants and animals living together
in a particular climate.
 There are many different climates on the earth, and different plants and animals
have adapted to living in certain conditions. These conditions, such as the range
of temperature and rainfall that occur on average in a particular place, are called
the climate.
 The biomes are generally distributed over the earth in horizontal bands that are
linked to climatic conditions associated with latitude and other geographical
features such as the proximity to large bodies of water or mountain ranges.
 The main factors that determine biome distribution include latitude, altitude, soil,
temperature, precipitation, and light.
 Terrestrial (land) biomes are defined by the dominant type of plant life (climax
community). The terrestrial biomes include the:
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Tropical Rain Forest,
Temperate Deciduous Forest,
Deserts,
Grasslands,
Taiga,
and Tundra.
 There are also two types of aquatic biomes:
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the marine (saltwater or ocean) biome,
and the freshwater biomes (rivers, lakes, ponds, swamps, bogs, etc.).
Biomes of Canada:
Due to its latitude, Canada has four main terrestrial biomes:
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Tundra
Boreal Forest/Taiga
Temperate Deciduous Forest
Grassland
Identify several plants and animals found in the Tundra biome (pp. 89); boreal forest
biome (p.89); Grassland biome (pp. 89); Temperate Deciduous Forest biome (pp. 89)
Identify the most important abiotic factors in the Tundra biome (pp. 89); the Boreal
Forest biome (pp. 89); Grassland biome (pp. 89); Temperate Deciduous Forest biome
(pp. 89)
Identify location of the Boreal forest biome in Canada (pp. 88); Grassland biome in
Canada (pp. 89); Temperate Deciduous Forest biome in Canada (pp. 88);
Explain why the Temperate Deciduous Forest biome contains the most biodiversity of the
four biomes (pp. 91)
Discuss the reasons for ecosystems that share similar abiotic features also
sharing similar animal life.
Abiotic factors (sunlight, temperature, water, soil, etc.) have a dominant role in the type
of plant life that can occur in a particular ecosystem. As plants form the basis of the food
chain, they play a major role in the animals that are found within a particular ecosystem.
Thus, if ecosystems have similar abiotic factors, they will have similar plant life which in
turn impacts the animals that prefer that ecosystem.
Describe the potential impact that a large scale logging project could have
on a native species such as the pine martin
Explain the impact that an abnormally dry summer could have on a bog
ecosystem
Describe how ecosystems are able to respond to changes and return to its
previous state
Describe how Canadian research projects in environmental science and
technology are funded.
Compare the risks and benefits to the biosphere of applying new scientific
knowledge and technology to industrial processes
Describe the role peer review has in the development of scientific
Knowledge.
Identify examples where scientific understanding about an ecosystem was
enhanced or revised as a result of human invention or related
technologies.