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.