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ENERGY FLOW IN ECOSYSTEMS
TOPICS LISTENERGY FROM THE SUN
PERCENTAGES
ALBEDO EFFECT
PHOTOSYNTHESIS and CELLULAR RESPIRATION
THERMODYNAMICS
ROLES IN ECOSYSTEMS
• KEYSTONE SPECIES
• ECOLOGICAL NICHE
• INTRASPECIFIC VS.
INTERSPECIFIC
COMPETITION
• EXOTIC SPECIES
PYRAMIDS
•PYRAMID OF ENERGY
•PYRAMID OF BIOMASS
•PYRAMID OF NUMBERS
WHERE DOES OUR ENERGY COME FROM?
The SUN is the source of energy for the vast
majority of life on Earth.
ENERGY FROM THE SUN
What happens to
the majority of the
Sun’s energy?
It heats the atmosphere, earth’s surface, and water.
PERCENTAGES:__27___ % is reflected by Clouds and Earth’s Surface
__69___ % warms the atmosphere, land, and hydrosphere
___1___ % generates wind patterns
_0.023_ % is used in the process of photosynthesis
ALBEDO EFFECTA measure of the AMOUNT of sunlight
REFLECTED from an object.
Expressed as a decimal value
Example: 27 % reflection by clouds is 0.27
What are examples of objects that REFLECT
sunlight?
In general, LIGHT-COLOURED objects such
as:_______________________________________
These highly reflective objects have a HIGH
ALBEDO.
What are examples of objects that
ABSORB sunlight?
In general, DARK-COLOURED objects such as:
_________________________________________
These light-absorbing objects have a LOW
ALBEDO.
Also, GREENHOUSE GASES have a low albedo.
ALBEDO EFFECT
PHOTOSYNTHESIS
What is it?
A biochemical process
whereby PRODUCERS use
the Sun’s energy, carbon
dioxide, and water to
produce sugar and oxygen.
GENERAL CHEMICAL EQUATION:
6 CO2+ 6 H2O + Sun’s Energy C6H12O6 + 6 O2
CO2 is carbon dioxide C6H12O6 is
glucose (sugar)
H2O is water O2 is oxygen
Oxygen is necessary for CONSUMERS.
Sugars are necessary as a usable form of
energy for nearly ALL LIFE on EARTH.
CELLULAR RESPIRATIONWhat is it?
A biochemical process whereby CONSUMERS release the energy stored in the sugar they ingest.
By eating sugars and breathing in oxygen, consumers produce carbon dioxide, water, and energy for life processes.
GENERAL CHEMICAL EQUATION:
C6H12O6+ 6 O2 6 CO2+ 6 H2O + Energy
WHAT KINDS OF LIFE
PROCESSES?
THERMODYNAMICS
What is THERMODYNAMICS?
The study of ENERGY
TRANSFORMATIONS from one
form to another (ex: chemical
energy to heat energy)
There are two Thermodynamic LAWS that
apply to ecosystems
FIRST LAW OF THERMODYNAMICS
Energy CANNOT be CREATED NOR
DESTROYED, only TRANSFERRED FROM
ONE FORM TO ANOTHER.
SECOND LAW OF THERMODYNAMICS
During energy transfers, SOME ENERGY is
“LOST” as HEAT ENERGY and is not passed
on.
PYRAMIDS
PYRAMID OF ENERGY
Recall from an earlier lesson that we can
represent ENERGY TRANSFER in an
ecosystem with a pyramid of energy, and
that only about 10 %of energy is passed
from one trophic level to the next.
There are 2 other types of pyramids that
are USEFUL GRAPHICAL INDICATORS of
ecosystem patterns:
PYRAMID OF BIOMASS
PYRAMID OF NUMBERS
BIOMASS
The mass of an organism WITHOUT water;
its dry weight. Measured in kg.
A PYRAMID OF BIOMASS is a graphical representation of the TOTAL BIOMASS of all the members of each trophic level.
Often similar in shape to a Pyramid of Energy.
PYRAMID OF NUMBERS
A graphical
representation of the
TOTAL NUMBERS of all
members of each trophic
level in a food chain.
Sometimes, these are
shaped liked pyramids,
but there are exceptions!
AN EXCEPTION:
For example, if the following was a rough
sketch of our pyramid of energy, would
the pyramid of numbers look the same?
ANSWER:
No, of course not! There would be more caterpillars than any other organism, so our “pyramid of NUMBERS” would look like:
HOMEWORK
Page 39, # 3, 4, 5, 7, 14
Draw 3 pyramids (energy, biomass, and numbers) for the following food chain:
HAWK (1, 10 J, 5 kg)
WOODPECKER (10, 100 J, 10 kg)
WORM (1000, 1000J, 50 kg)
FIR TREE (1, 10000J, 150 kg)
ROLES IN ECOSYSTEMS
It is time to discuss some of the
interrelationships that take place in
ecosystems between species.
Some specific roles organisms can take
on include:
KEYSTONE SPECIES
ECOLOGICAL NICHE
INTRASPECIFIC VS. INTERSPECIFIC
COMPETITION
EXOTIC SPECIES
KEYSTONE SPECIES
A species that is considered so important to
ECOSYSTEM STABILITY, that if that species
declined, the ecosystem might collapse.
Why is it called “keystone”?
It is an analogy for a
keystone that holds together
an archway.
Example:
SEA OTTER is a keystone in the
CALIFORNIA KELP ecosystem
Without otters, kelp does not grow.
ECOLOGICAL NICHE
An organism’s NICHE is its “role” that it
plays in a particular ecosystem.
It includes everything an organism does
to survive and reproduce, including:
•Feeding relationships
•Habitat
•Breeding grounds/behaviours
•Activity times
•Competitive relationships
Organisms tend to have UNIQUE niches,
based on where and how they are best
adapted to survive.
EXAMPLE:
Galapagos Island Finches
Found on the Galapagos Islands,this little finch
evolved into many SUBSPECIES , all adapted to a
DIFFERENT NICHE.
http://www.youtube.com/watch?v=l25MBq8T77w
SPECIES COMPETITION
Sometimes in nature there is COMPETITION
for NICHES when two or more organisms
have similar requirements for SPACE, FOOD,
and/or WATER.
“Survival of the Fittest” usually prevails
2 MAIN TYPES:
INTRASPECIFIC COMPETITION
Between the SAME SPECIES
EX:___________________________________________________
INTERSPECIFIC COMPETITION
Between DIFFERENT SPECIES
EX:____________________________________________________
INTRASPECIFIC COMPETITION
SAME SPECIES COMPETING
INTERSPECIFIC COMPETITION
DIFFERENT SPECIES COMPETING
EXOTIC SPECIES
These are NON-NATIVE species that are
not natural parts of ecosystems.
Compete INTERSPECIFICALLY with native
species in the area.
Examples:
Moose in NL –4 in 1904
Green Crab in Atlantic Canada
Zebra Mussels (p. 42-44)
EXOTIC SPECIES –GREEN CRAB
HOMEWORK
READ P. 42-44
P. 44, # 2, 3, 4
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