Transcript Chapter 6 Ecosystems and Their Interactions “You could cover the whole world with asphalt, but sooner or later green grass would break through.” Ilya.

Chapter 6
Ecosystems and Their
Interactions
“You could cover the whole world with
asphalt, but sooner or later green grass
would break through.” Ilya Ehrenburg –
Russian writer
Energy Flow in Ecosystems
The ultimate source of energy for all living
things is the sun.
Plants, algae and some bacteria
can capture solar energy and
store its food.
What is this process called?
Photosynthesis
Photosynthesis is a chemical reaction that
requires H20 and CO2.
Producers are organisms that produce
their own energy. They are also known as
autotrophs.
Consumers are organisms that get their
energy by eating other organisms. They
are also known as heterotrophs.
Important: All living things get
energy from the sun, some
directly and others indirectly.
List examples:
One exception to the rule:
Deep ocean communities that have a
bacteria that make energy from Hydrogen
Sulfide released through fissures in the
ocean floor.
What eats what list …define
together
Producer
–Produces its own food (energy)
through photosynthesis
Consumer
–Eats other things to convert to
energy
There are four types of
consumers Can you guess
what they are?
Herbivore
Carnivore
Omnivore
Decomposer
The process of breaking down
food to yield energy is called
cellular respiration.
Not to be confused w/ respiration
Does anybody know the chemical
equation????
C6H12O6 + 6O2 --->6CO2+6H2O
+Energy
Name three reasons for making
energy?
Immediate
Fix
energy-
Things
Store
for later
How is energy transferred
through (in) ecosystems?
Food Chains and Food Webs
Food Chains show the sequence in
which energy is transferred from one
organism to the next as one eats the
other.
Food Webs show the many feeding
relationships in an ecosystem.
There is a 90% energy
loss between Trophic
Levels
Tertiary
Consumer
.1%
Secondary Consumers
1%
Primary Consumers
10%
Producers (Plants)
100%
What role does sunlight play in an
ecosystem?

It provides the light that is transferred
into energy..

Could there be life on earth w/out
producers?

Would 20 acres of land support more
people if they ate only plants or plants
and animals both?
The Cycling of Materials
The Water Cycle:
The water cycle is the cycling of
water between the earth’s
atmosphere and its surface.
The process by which water
returns to the surface is called
Precipitation.
Precipitation falls in three states.
Rain (liquid)
Sleet (mix)
Snow or Hail (solid)
Transpiration- water released from plants
(remember photosynthesis)
H2O + CO2 + Light ---- C6H12O6 + O2
Groundwater may flow below the
surface and above ground at
different times
(How could pollution present a
problem and where is it most
sensitive?)
The sun is the driving force
behind the cycle.......
Describe why!!!!
The Carbon Cycle
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Problem exists because we are burning large
quantities of fossil fuels and over
concentrations of CO2 exist.
Plants also give off a certain amount of
carbon as cellular respiration is carried out.
C6H1206 + O2 ----------> CO2 + H2O +
Energy
Fossil fuels are Hydrocarbons (bonds of H &
C)
When burned C is released into the
atmosphere.
The Nitrogen Cycle:
78 % of the atmospheric gases are
nitrogen.

There are few species that can use N2 directly from the
atmosphere.
 These are bacteria and are known as nitrogen-fixing
bacteria.
 Fixing means transforming to usable forms.
 These bacteria provide N2 a way into plants and animals
eat plants as a source of nitrogen.
 These plant are called Legumes.
 Decomposers also provide a closure to the N2 cycle by
returning the fixed nitrogen back to the ecosystem.
What is Nitrogen used for in our bodies?
Nitrogen is a component in the production
of protein.
 Proteins are our bodies building blocks.
 They help build and fix things!!!

Succession
Succession is a regular pattern of change
in a community.
 This may take place over hundreds or
thousands of years.
 It occurs because of proper conditions and
seed dispersal.

What causes succession?
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Proper conditions and seed dispersal
Must be left undisturbed
Each new community makes it difficult for the
previous to survive.
ie/ The shrubs around your house make it
difficult for the grass to grow underneath.
A pine forest with larger pines shadow the
smaller ones
But oaks can grow taller and need less light
so they succeed and cause problems for the
smaller pines.
Primary Succession
The first group of plants to begin growing
in in an ecosystem.
 Usually small
 Referred to as Pioneer Communities
 Pioneers are those plants which first
colonize any newly available land.

Secondary Succsession
The volcanic eruption around Mt. St.
Helens leveled about 45,000 acres.
 It has since started to grow back...
 This is not primary succession.
 It is secondary. (a community already
existed there. )
 Secondary Communities are the second
group of plants to take over and area.

Questions

How does the water cycle help succession?

Explain why it could be damaging in the long run
to put out forest fires...

What are lichens?
 What is the role of lichens in primary
succession?
 If a lake becomes a forest is this primary or
secondary? Explain...