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Science 10
Unit 1: Sustainability of Ecosystems
G.Burgess
Sept.2006
Terms to know:
Ecosystem
Producer
Primary consumer
Secondary consumer
Trophic level
Detritivore
Decomposer
Pyramid of numbers
Biomass
Pyramid of biomass
Pyramid of energy flow
Carrying capacity
Competition
Intraspecific
competition
Interspecific
competition
Population density
Density-dependent
factors
Productivity
Biological
magnification
Sustainability of Ecosystems
Sustain / Ability Ecology / System
=maintain
=competency
=Environment
=organization
:the ability for people to interact with the environment so
that they may prosper and the environment may
prosper as well.
Question: Can we continue to mine for metal resources
and fuel without destroying the environment?
**The diamond mines of N.Territories must
reintroduce the organisms and non-living materials
that were present prior to the mining.
Human need for nature
What materials do humans collect
from the natural environment?
IE.
Where do we get the materials
we eat?
How do these materials interact
with the environment?
Capturing Energy from the
SUN.
• All organisms rely on the sun for
energy.
• Energy makes it possible for
organisms to perform growth,
reproduction, nutrition, transport of
materials, react to the environment,
metabolize materials, assimilate and
synthesize materials
• Energy is what enables our bodies to
perform the chemical reactions
required for life.
Ecosystem
• Includes all organisms in an area that interact with
one and other, and the non-living environment
(sunlight, water, soils, etc…)
• The interactions of organisms and the cycling of
materials within an ecosystem can be shown through
food chains and food webs.
• Organisms may be classified as producer or
consumer depending on their roll in the ecosystem.
• Consumers may be classified as herbivores,
carnivores, omnivores, detritivores, or decomposers.
Ecosystem
• Producer:
• all green plant, blue-green algae
(cyanobacteria/ archaeobacteria)
• Any organism that is capable of
creating its own food
• Consumer:
• all animals, fungi, animal like protists,
some bacteria
• Any organism that relies on another for
its food.
Types of Consumers
• Herbivores: plant eating organisms
• Carnivores: meat eating organisms
• Omnivores: Eats both plants and meat
• Detritivore: organisms that feed on dead
decaying organic matter
• Decomposer: organisms that breakdown
large compound (ie. proteins) into smaller
compounds that may be used by producers
Food Chain/ Food Web
• Perform Laboratory Activity 1.
• Exploring Energy Cycling
Ecological Pyramids
Food Pyramids
We use pyramids to express relationships between
organisms.
1. Pyramid of Numbers: used to demonstrate the relation
between the populations found with in trophic levels.
ie. Fig 1.8 pp.14 demonstrates how the population is
reduced as the trophic level increases. NOTICE: the
population of grass compared to the population of
mice. Which is larger? Why?
Examine Fig.1.10 on pp.15. Why is the population of
trees much smaller than the population of herbivorous
insects?
Ecological Pyramids
2.
Pyramid of biomass: demonstrates a relationship
between organisms by combining their size with
their population.
•
This pyramid shows how the biomass
decreases as the trophic level increases.
•
NOTICE: fig.1.12 shows how the pyramid can
be reversed if the reproduction rate of the
producer is faster than the reproduction rate of
the consumer.
•
QST: What would happen if the environment
changed so that the phytoplankton could not
reproduce as fast?
Ecological Pyramids
3.
Pyramid of Energy Flow: shows the changes of
total chemical energy that moves from trophic level
to trophic level.
•
Energy is continually lost as trophic levels
increase
•
Producers always have the most energy
NOTICE: there is always a drop in energy between
levels
Carrying Capacity
•
•
The largest population that can be sustained by an
environment.
Factors that influence the carrying capacity;
1. Materials and energy: there is a limited supply of
sunlight, water, soil nutrients,
2. Food Chains: the population of one species limits the
populations of successive species
3. Competition: limits of food/shelter/mates/space for
living generates competition amongst and between
species. This inevitably influences the populations of
individual species.
Competition
• Intraspecific competition: between members of
same species.
• Interspecific competition: between different species
• Population density: refers to the population of a
species that can survive in a certain area. This is
closely linked with the carrying capacity for an area.
• Density-dependant factors: those factors that
increase stress as the population increases.
• Density-independent factors: factors that limit
population no matter what the size was initially.
Pop-Bottle Terrarium