Transcript ECOLOGICAL PYRAMID AND BIOLOGICAL MAGNIFICATION NOTES

ECOLOGICAL PYRAMID,
ENERGY AND BIOLOGICAL
MAGNIFICATION NOTES
ENERGY
 The ability to do work & transfer heat
 Some Different Forms of Energy:
1. Kinetic Energy – moving energy
2. Heat – kinetic energy of molecules &
atoms
3. Electricity – movement of charged particles
4. Chemical Energy – energy stored in bonds
of molecules
5. Gravitational Potential Energy – energy
stored by an object that can fall
Energy
All energy used in biological
systems originally comes from the
sun
The amount of energy gained by
producers is defined as 100% of
the energy available to biological
systems and is stored as
chemical energy
Law of Conservation of Energy
Energy cannot be created or
destroyed!!
When a consumer eats a producer,
the chemical bonds in the producer’s
molecules are broken and new
molecules are made in the consumer
which releases energy (this is the
energy used by the consumer)
Mass
In no part of the food chain
process is any matter destroyed
(no atoms disappear)
So mass is also conserved – Law
of Conservation of Mass
Mass can be neither created or
destroyed
BIOMASS
Total mass (amount of
living tissue) of all the
organisms within a given
trophic level
Only a small fraction of the biomass
from one trophic level moves to the next
2 Reasons for this:
Many organisms are not consumed
by organisms at the next trophic level
– energy is not available for transfer
Some of the biomass at each level
consists of materials consumers won’t
eat – bones, teeth, beaks, claws,
shells, wood
ECOLOGICAL PYRAMID
Shows the relationships between
producers and consumers at the trophic
levels in an ecosystem
Owls
Snakes
Rabbits, mice
Grass, flowers
WHY A PYRAMID SHAPE?
In most food chains fewer organisms
occupy each higher trophic level (lots
of producers, many primary
consumers, fewer secondary
consumers and very few tertiary
consumers)
Energy in a Trophic Pyramid
The energy the producers gained from the
sun has 2 directions it can go:
1. up to the next trophic level
2. released as heat
10% of the energy is consumed by the next
trophic level and the rest (90%) is released
into the environment as heat
Notice this adds up to 100% because of the
Law of Conservation of Energy
Energy in a Trophic Pyramid, cont.
The same is true for primary consumers –
the energy that primary consumers gained
from the producers has 2 directions it can go:
1. up to the next trophic level
2. released as heat
10% goes to the next trophic level and 90%
is released as heat, which again adds up to
100%, keeping in line with the Law of
Conservation of Energy
10 PERCENT LAW
Energy available at each trophic level is
about 1/10 the energy available from the
level below
20
200
2,000
20,000
3rd
consumers
.1%
2nd consumers
1st consumers
producers
1%
10%
100%
Heat
As said earlier, much of the energy from
one level to the other on a pyramid is
released as heat
Heat can move from one place to another
in only 3 ways:
1. Conduction
2. Convection
3. Radiation
Heat, cont.
 Conduction – when two objects come into physical
contact and heat is transferred (ex. Touching the
stove)
 Convection – when heat moves through a fluid
(liquid or gas) because hot fluids rise and cold
fluids sink (ex. Holding your hand above the stove
and getting hot)
 Radiation – when heat is transferred by
electromagnetic energy (like light and infrared); the
radiation causes the molecules to start moving (ex.
You get hot while outside because the sun’s
radiation heats you up)
BIOLOGICAL MAGNIFICATION
The buildup of a pollutant in
organisms at higher tropic levels in a
food chain
The concentration of a pollutant (like
DDT) multiplies as it passes up the
food chain from producers to
consumers, so the amount of DDT in
top-level consumers can be magnified
nearly 10 million times