Download Ecology

Unit #1
Ecology – Living things and the Environment
Chapter 5 & 37
“Big Idea”


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Living things need to obtain & use energy
in order to do work!
Where do they get this energy from?
Ecology – the study of how living things
interact with each other & their
environment
WHAT DO WE CALL THE ENERGY IN OUR FOOD?

Calories
 Measure

the amount of energy stored in your food
Where is the energy stored in your food?
 Molecules
that are bonded together to make that
food.

Bonds are a form of chemical energy!
BONDS

When you break a bond…
 You
release energy!
 Decomposition
 Exergonic Reaction

When you make a bond…
 You
store energy!
 Synthesis
 Endergonic Reaction
IS ANYTHING 100% EFFICIENT?



Not all the chemical energy stored in food can be used to
do work.
The portion of chemical energy you can use (or that is
“free”) to do work is called: free energy
 The more free energy you can obtain from what you eat,
the more efficient you are!
Any free energy left over (after you have done your work) is
then stored.
BASICALLY 2 WAYS LIVING THINGS GET THIS
ENERGY…

Heterotroph
 Obtain
energy from other living things.
 AKA  EAT
 Cellular Respiration

Autotroph
 Use
surrounding to make their own food!
 Plants  photosynthesis
 Bacteria  chemosynthesis
ENERGY & ECOSYSTEMS
Would a deer come running out of the woods
and try to eat you? Why?
 Organisms have certain roles!
 Autotrophs – producers
 Heterotrophs – consumers

 Special
Case – Decomposers (consume dead or
decaying matter)
 Bacteria,
fungi, worms, vultures
 Recycle important nutrients (not energy!) back into soil for
producers such as plants to use again
TYPES OF CONSUMERS

If you eat plants (herbivore) you are a primary (1o)
consumer
If you eat herbivores (carnivore) you are a secondary
consumer (2o)
If you eat 2o consumers then you are a….

Trophic Levels


Food Web
More Realistic than chain
 Display the flow of energy through an
ecosystem

 Arrow points in the directions the energy is traveling!

Ecosystem – all the living & nonliving things in
an area
 All Living Things – Biotic Factors
 All Non Living Things – Abiotic Factors
Some More Vocab…

Habitat – places where particular organisms live

Niche - organism’s role in its environment
The Re-Introduction of Wolves
The mouse population
would most likely increase
if what happened?
What would cause the
mouse population to
decrease?
Using this information, why
do you think we have such
an overpopulation of deer in
New Jersey?
Laws of Thermodynamics

Study of Energy Changes

1st Law – energy cannot be created or destroyed,
but it can change forms.
○ Law of conservation of energy
 initial
energy = final energy
○ Forms of Energy
 Chemical (bonds)
 Heat
 Work
 Light
 Sound
What does the 1st law mean for living things?

Living things can not create their own energy, they must
obtain it from their environment!

Amount of Usable, Available Energy (chemical energy) is
always decreasing in an ecosystem because it is being
turned into other (unusable) forms of energy.

Relate to food web/food pyramid  need more
autotrophs to support a smaller number of heterotrophs

Why it looks like a pyramid!
2nd Law

Systems tend to change in a way that increases
disorder or entropy!

What does this mean for living things?


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Organisms must be well organized to remain alive & grow!
Use energy to fight against entropy to maintain homeostasis
1-way flow of energy
• Biomass – dry weight of all
organic matter contained
within a trophic level
(grams/kg)
• Only about 10% of the
energy stored in biomass is
transferred from 1 level to
the next
– What happens to the rest of it?
• Used up or Lost as heat
energy
Put this information all together!
• Using what you have just learned, why can’t
trophic levels go on forever (5,6,7th level
consumers)?