2. Main Ideas
1. What happens to matter in an
ecosystem?
2. What happens to energy in an
ecosystem?
3. Where do living things get their energy
and matter?
3. Interdependence
All living things are
connected to other
living things, both
directly and indirectly.
Living things eat and/or
get eaten
Living things obtain
chemicals that came from
other living things
The actions of living
things affect other
organisms
4. So…
Ecosystems require MATTER and ENERGY
Matter is stuff – atoms that are used to make
molecules
Energy is… Not created or
destroyed, only
converted from
1 form to
another
5. Essential for all life
Energy
Matter
Can be symbolized by
Sunlight Producer
Primary
consumer
Secondary
consumer
6. An energy Pyramid
Gets smaller as it
goes up since there
is less and less
energy as you go up
7. Pyramid of
numbers
How many
organisms are at
each level
Usually mostly
producers, then
primary
consumers, then
secondary and
so on
100,000 plants
1000
voles
1 owl
8. Pyramid of
numbers
Could look like
this:
1 oak tree
supports lots of
primary
consumers,
which support
fewer secondary
consumers, then
even fewer
tertiary, etc.
1 oak tree
1000
caterpillars
50 bluetits
1 sparrow
hawk
10. Light energy to chemical
energy (photosynthesis)
Gross Primary Productivity – all
the light energy that is converted to
chemical energy in an ecosystem
Not all of this is available to
consumers though, because the
plants need some for themselves
Net Primary Productivity – the
chemical energy available to
consumers
11. Ecosystems with high NPP
Tropical rain forests
Estuaries
Coral reefs
Open ocean (just because so much of the
planet is covered in it)
12. What happens to energy in an ecosystem?
First – write your response
Use these terms
%
Trophic levels
Autotrophs
Heterotrophs
Primary
productivity
What to do
Younger person goes
first
Must use at least 3
terms in their answer
Older person must
write their answer
Switch – same rules
13. Giraffes eat the grass
Lions eat the giraffes
And when they die, they
become part of the soil
and feed the grass
15. Some basics
In all cases (except water) – plants get the C, N, P, and S first, then
animals get it from their food
Decomposers are vital to recycling these nutrients and returning them
to the earth so plants can get them again.
C,N,P,S
17. Human Impacts
1. We use fresh water faster than it is
replenished naturally
2. Water pollution
18. Quick Think
What do you know for sure about
the water cycle?
“I know for sure that…”
20. Where is the Carbon?
– CO² gas in the atmosphere (air)
– dissolved CO2 in the oceans (water)
– Carbon in organic molecules in every living
thing
– Carbon is in fossil fuels and sedimentary
rocks
21. Review - Photosynthesis
Plants take CO2 + water + energy from the sun
And make
Glucose (sugar) and oxygen
CO2 + H2O C6H12O6 + O2
22. Carbon diffuses into water
Carbon in the atmosphere diffuses into the
oceans
Forms carbonic acid
– CO2 + H20 H2CO3
Too much CO2 in oceans leads to ocean
acidification
29. Where is the nitrogen?
Most of the
nitrogen (the main
reservoir) is in the
air.
– 78% of our air is
nitrogen gas
– It is not usable in this
form
– It must be “fixed”
first
30. How does the nitrogen get fixed?
–By
lightning
~10%
47. Human Impact on Ecosystems
1. Nutrient enrichment – adding
excess nutrients to aquatic
ecosystems
2. Acid precipitation – pH less
than 5.6, harms trees, aquatic
ecosystems,
3. Biological magnification –
toxins accumulate in the tissues
of organisms, PCBs and DDT
4. Rising atmospheric CO2 –
global warming
5. Depletion of the ozone layer –
CFCs, burns leaves and skin