Download Set 2

ENERGY FLOW IN ECOSYSTEMS
TOPICS LIST
ENERGY FROM THE SUN
 PERCENTAGES
 ALBEDO EFFECT
 PHOTOSYNTHESIS and
CELLULAR RESPIRATION
 THERMODYNAMICS
ROLES IN ECOSYSTEMS
• KEYSTONE SPECIES
• ECOLOGICAL NICHE
• INTRASPECIFIC VS.
INTERSPECIFIC
COMPETITION
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 wate
PERCENTAGES:
_______ % is reflected by Clouds and Earth’s Surface
_______ % warms the atmosphere, land, and hydrosphere
_______ % generates wind patterns
_______ % is used in the process of photosynthesis
ALBEDO EFFECT
A 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
glucose (sugar)
 H2O is water
C6H12O6is
O2 is oxygen
Oxygen is necessary for CONSUMERS.
Sugars are necessary as a usable form of
energy for nearly ALL LIFE on EARTH.
CELLULAR RESPIRATION
 What
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?
HOMEWORK
 Page
33
 Numbers 4 a), c), d)
THERMODYNAMICS
What is THERMODYNAMICS?
The study of ENERGY
TRANSFORMATIONS from one
form to another (ex: chemical
energy to heat energy)
2 Thermodynamic LAWS that apply to
ecosystems are:
FIRST LAW OF THERMODYNAMICS
Energy CANNOT be CREATED NOR DESTROYED, only
TRANSFERREDFROM 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.
Water weight varies greatly in living tissue,
so it is more accurate to eliminate it.
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
 WORM
 FIR
(10, 100 J, 10 kg)
(1000, 1000J, 50 kg)
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, 600 miles west of
Ecuador in South America. Largely untouched by
human impacts, Charles Darwin studied these
finches in 1835. By most accounts, a windstorm
blew one finch species to the island. Left
undisturbed for many centuries, and with very little
competition and many available niches, this little
finch evolved into many SUBSPECIES , all adapted
to a DIFFERENT NICHE.
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