Energy Flow
How does energy move through the ecosystem?
http://www.armofthesea.info/images/landscapes/crommet_lg.jpg
Conservation:• Law of Conservation of Matter -
– In any ordinary physical or chemical change, matter is neither created nor destroyed, only transformed from one form to another.
• Law of Conservation of Energy -– In any ordinary physical or chemical change,
energy is neither created nor destroyed, only transformed from one form to another.
Energy:
• 2nd Law of Thermodynamics:–When energy is changed from
one form to another, some energy will be lost to the larger environment.• Nothing is ever 100% efficient.• This is due to entropy (nature’s tendency
towards randomness).
How does energy flow through ecosystems?
• Food Chain: A simple diagram of one string of feeding relationships in an ecosystem, showing the direction of the transfer of energy in that system.
Sun Grass Rabbit Wolf Bacteria
Soil
Producers
• Organisms that make their own food from inorganic molecules and energy. – eg. Plants, blue-green algae – Most accomplish energy building through
photosynthesis • H20 + Sunlight + CO2 Sugar + O2
Inorganic Molecules = molecules that
are not part of a living organism
Energy is almost always from the sun
(very rare exceptions)
What are the parts of a food chain?
Consumers• Organisms that cannot make own food.
– eg. all animals, fungi and most bacteria – Obtain energy by eating other organisms —
through a process called cellular respiration • Sugar + O2 CO2 + H20 + energy
Decomposers• Bacteria and fungi
that break down organic material
Decomposers are essential to
ecosystem health because they
recycle nutrients back for producers
to reuse.
Food Web:• a group of
food chains showing all of the feeding relationships in an ecosystem.
Food Web
Human Wolf FoxSheep
BacteriaRabbit Mice Deer
Grass Flower Carrots
Nutrient Rich Soil
Sun
Biological Magnification
• Increasing concentration of a substance in organisms in higher trophic levels in a food chain or web.
Many toxins in the water
Many toxins in the person
• Biological Magnification- accumulation of increasing amounts of toxin within tissues of organisms.
Video on Biological Magnification
Food Webs con’t:• Trophic level — a
layer in the feeding relationship of an ecosystem, one link in the food chain/web.
• Biomass — total amount of organic material present in a trophic level.
Organic = is currently living or lived in the past
So, all producers are at the same trophic level and all primary consumers are at the
next trophic level.
Energy Pyramids• Another way to look at
trophic levels.• a diagram showing the
relative amounts of energy/biomass in the different trophic levels.
• Lowest trophic levels are at the bottom: Producers have the greatest biomass.http://www.earthforce.org/files/
1284_image2_Energy_Pyramid_for_Galvbay.jpg
http://www.vtaide.com/png/foodchains.htm
Example of an Energy Pyramid
MAN
FOX
RABBIT
100 % of the sun’s energy
10%
1%
0.1%
10%
10%
10%
1 MAN
10 FOXES
100 RABBITS
1000Bunches ofGRASS90%
90%
90%
Energy Lost during
conversion to heat, waste….
Grass
Rabbit
- The decreasing size of the pyramid shows that each level of the pyramid has a smaller and smaller number of those organisms.