1. Ecological Niches and Cycles

2. Ecological Niches
Habitat: The natural
home of an organism. It
provides refuge and
food.

3. Ecological Niches
An ecological niche is
the role (functions) of
a species in an
ecosystem and its
habitat.

4. Ecological Niches
The ecological niche of a species includes:
1) What it feeds on
2) What feeds on it

5. Ecological Niches
3) How the species behaves in its environment
4) All the factors that the species needs to survive,
remain healthy and reproduce

6. Ex. What is the ecological niche of black bears?
– Live in forests.
– Feed on nuts, berries,
insects, and small animals.
– Fed on by blood-feeding
insects and parasites.
– Help carry seeds of berries
for long distances (in their
digestive systems) and
expel them allowing the
seeds to grow.
Ecological Niches

7. The Nitrogen Cycle

8. • N2 (nitrogen gas) is the most abundant gas in the
atmosphere (78%)
• Nitrogen is needed to make protein and DNA.
• However, it is not in a usable form for plants to take up.
• Animals obtain the nitrates (NO3
−) from eating plants.
The Nitrogen Cycle

9. Nitrogen Fixation:
• Nitrogen fixation is the process of turning nitrogen
gas into a useable form, nitrate, NO3
-
• Two methods:
a) lightning strikes
b) by certain types of bacteria which live in the soil.
The Nitrogen Cycle

10. Nitrogen in Agriculture
• Farmers often plant crops like alfalfa and clover to
increase the nitrate, NO3
-, levels in the soil.
• Soil is often aerated (holes are dug) to allow oxygen to
facilitate the process of nitrogen fixation.
• Fertilizers also increased the nitrate level.
The Nitrogen Cycle

11. Denitrification
• There are some bacteria (called denitrifying bacteria)
which will break down the nitrate, NO3
- back to nitrogen
gas in a process called denitrification.
The Nitrogen Cycle

12. The Carbon Cycle

13. Organic
- Contain atoms of C, H and
sometimes O and N.
- Examples: protein, sugar
and fats.
Inorganic
- Does not contain a
combination of C and H.
- Examples: CO2 and H2O
The Carbon Cycle
Before we begin…

14. Are the following molecules organic or inorganic?
The Carbon Cycle

15. Matter must be recycled to maintain life
1) Digestion - through digestion complex organic
molecules are broken down into simpler molecules.
2) Decay – After death decomposers break down the
organic matter into small inorganic molecules (plants
use these inorganic molecules to make food for
themselves)
The Carbon Cycle

16. First Experiment
• Candle in Jar A burned
for 3 minutes
• Candle in jar with mint
plant burned for 5
minutes
Why do you think?
Joseph Priestley (1733–1804) began a series of
experiments that would reveal the essential role of air in the
growth of green plants.
The Carbon Cycle

17. Second Experiment
• Placed mouse in jar
without plant and it
died
• Placed mouse in jar
with mint plant and
lived for a longer period
of time. (eventually
died)
The Carbon Cycle

18. Conclusion
• Plants and animals help
each other.
• Now scientists know
that plants use carbon
dioxide and water to
make sugar and oxygen
is released as sugars are
made. We call this
process
PHOTOSYNTHESIS
Photosynthesis:
6H2O + 6CO2 ----------> C6H12O6+ 6O2
The Carbon Cycle

19. Cellular Respiration
• The mouse used oxygen
from the plant to break
down sugars. When
your body breaks down
sugar carbon dioxide
and water are released.
• This process is called
cellular respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O
The Carbon Cycle

20. Definitions
• Cellular respiration
– Process of converting
food energy into
chemical energy that can
be used by all cells in the
body
– Occurs in the
mitochondria
C6H12O6 + 6O2 → 6CO2 + 6 H2O
The Carbon Cycle

21. Definition
• Photosynthesis
– Process of converting
light energy into stored
food energy
– Occurs in chloroplasts of
autotrophs
6CO2 + 6H2O C6H12O6 + 6O2
The Carbon Cycle

22. Summary
• There is a balance
between oxygen and
carbon dioxide within the
biosphere
• Plants provide oxygen
and sugars
• Animals provide CO2 and
water.
• Processes of
photosynthesis and
cellular respiration are
complementary not
opposite. (Steps involved
are different)
The Carbon Cycle

23. The Carbon Cycle
• All living things contain carbon
• 3 sources of carbon in food:
– Carbohydrates (spinach, oranges,
sugar, bread)
– Lipids (oil, butter)
– Proteins (meat, eggs)
• Carbon is recycled through
cellular respiration and
photosynthesis and this
relationship is called the
carbon cycle

24. Fast Track Carbon Cycle: (minutes to years)
Atmospheric CO2
↓
Photosynthesis in Autotrophs
↓
Digestion in Organisms
↓
Cellular respiration in
organisms
↓
Decomposition of organisms
The Carbon Cycle

25. • Death of living organisms
results in decomposition of
organic molecules
(decomposers)
• Decomposition is very slow
in oxygen-poor areas such
as bogs.
• As a result carbon atoms in
decaying matter remain
trapped between rocks and
are compacted over time
resulting in the formation of
coal (fossil fuel)
The Carbon Cycle
Slow Track Carbon Cycle on Land: (over millions of years)

26. Bogs
• Bogs receive all or most of
their water from the rain that
comes down. As a result, bogs
are low in the nutrients
needed for plant growth. Bogs
are also acidic due to the
presents of peat mosses.
The Carbon Cycle

27. • Carbon atoms are returned to the atmosphere by
natural processes such as:
–Uplifting
–Weathering
–Erosion
The Carbon Cycle

28. Weathering
• weathering is simply the chemical or physical
breakdown of rock material
The Carbon Cycle

29. Erosion
• is the removal or
transportation of material by
agents as running water, ice,
wind, etc.
• Eg. Bryce Canyon in Alaska
The Carbon Cycle

30. Uplifting
• Material that has been
“pushed” up from
underneath the ground.
– Earthquakes
– Volcanoes
– Events are due to the
movement of the Earth’s
plates (called plate
tectonics)
The Carbon Cycle

31. • Oil (fossil fuel)
• Trapped in similar
fashion as coal,
however oil is trapped
under the ocean floor
– Decaying matter is
trapped under sediment
(rocks) in a low oxygen
environment
The Carbon Cycle
Slow Track Carbon Cycle in water: (over millions of years)

32. Dissolved Carbon
• In the ocean there is a
tremendous amount of
dissolved CO2 (inorganic
carbon)
• Some of the CO2 reacts with
the sea water to form
carbonate ions and
bicarbonate ions
• Carbonates combine with
calcium to form calcium
carbonate, in turn hardening
the skeletons (shells)
CO3²ˉ (carbonate ion)
HCO3¯ (bicarbonate ion)
The Carbon Cycle
Slow Track Carbon Cycle on Land: (over millions of years)

33. The Slow Track Carbon Cycle in Water
• Limestone
– When aquatic organisms die
their skeletons form sediments
(rocks)
– Carbon can be trapped in rocks
for millions of years until it is
brought back to the surface
• Volcanic activity
• Acid rain falling on exposed
limestone will cause a
release of carbon dioxide
The Carbon Cycle

34. Human Impact
Greenhouse Effect
• gases in the atmosphere (water vapor, carbon dioxide, etc.)
trap energy from the sun.
The Carbon Cycle