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1. •Ecosystem: Defined area in which a community lives
with interactions taking place among the organisms
between the community and its non-living physical
environment.
•An ecosystem is formed by the interactions between all
living and non-living things

2. Ecosystems: Fundamental Characteristics
•Structure:
• Living (biotic)
• Nonliving (abiotic)
• Process:
• Energy flow
• Cycling of matter (chemicals)
• Change:
• Dynamic (not static)
• Succession, etc.

3. An ecosystem consists of two main
components
Abiotic or Non-living components.
Biotic or Living components.

4. Abiotic or Non-living components.
1) Outside energy source
2) Physical factors that determine
weather, climate
3) Chemicals essential for life

5. Outside Energy Source

6. Physical factors that determine weather, climate
Heat
Wind
Precipitation
Topography

7. Heat
 Location
 Reflection
 Retention

8. Wind and Precipitation
•Uneven heating
•Ascending,
descending air
masses

9. Chemicals Essential for Life
•Elements and
compounds
•Recycled
between biotic
and abiotic parts

10. The Biotic Components of Ecosystems
 Producers
(autotrophs)
- Photosynthesis
 Consumers
(heterotrophs)
- Aerobic
respiration
 Decomposers

11.  Producers
(autotrophs)
•The conversion of light energy to
chemical energy is called “gross
primary production.”
•Plants use the energy captured in
photosynthesis for maintenance
and growth.
•The energy that is accumulated
in plant biomass is called “net
primary production.”

12. Consumers
• Primary, secondary, tertiary, etc.
• Herbivore - plant eater
• Carnivore - meat eater
•Omnivore - mixed plant/animal diet

13. Decomposers
 Digest complex organic chemicals into inorganic
nutrients that are used by producers
 Complete the cycle of matter

15. 1. The Producers, the green plants, fix radiant energy(solar energy) and with
the help of minerals take from their edaphic(soil where they grow) or
aerial environment and build up complex organic matter. These are their
food. So, with the help of solar energy they convert the chemical energy
of the food to kinetic energy and finally heat energy.
2. The animals eat up plants and other animals as food. So, the energy is
transferred through food to animals.
3. When plants and animals die, then decomposers(like certain bacteria and
fungi) act on their dead bodies and decompose them into simple materials
like carbon dioxide, water and minerals which go back to air, water
bodies and soil from where they were taken.

16. Ecosystem Function
One-way flow
of energy
Cycling of
matter

17. Matter and Energy Flow in Ecosystems
Food chains Food webs
Food chains/webs show
how matter and energy
move from one organism
to another through an
ecosystem.

18. Food Chains
•The producers, consumers, and decomposers of each
ecosystem make up a food chain.
•There are many food chains in an ecosystem.
•Food chains show where energy is transferred and not who
eats who.

19. Example of a Food Chain

20. Food Webs
All the food chains in an area make up the food web of the area.

21. Natural
1.Terrestrial ecosystems (grasslands, forests, desert ecosystems)
2.Aquatic ecosystem
a.Lentic (Stagnant water) like lake, ponds etc.
b.Lotic (Flowing water) like river, ocean, sea, etc.
Artificial
1.A crop land, garden, aquarium, park, kitchen garden.

22. Grassland Ecosystems

23. Forest Ecosystems

24. Desert Ecosystems

25. Lake & pond Ecosystems

26. Ocean & sea Ecosystems

27. River Ecosystems

28. Crop land Ecosystems

29. Garden Ecosystems

30. Aquarium Ecosystem

31. kitchen garden Ecosystems

32. Biogeochemical or nutrient cycles
The movement (or cycling) of matter through a system.
Matter mean: elements (carbon, nitrogen, oxygen) or molecules (water).

34. Sources
•Lightning
•Inorganic fertilizers
•Nitrogen Fixation
•Animal Residues
•Crop residues
•Organic fertilizers

35. Nitrogen is a key element for
• amino acids
• nucleic acids (purine, pyrimidine)
•cell wall components of bacteria
(NAM).

36. Nitrogen Cycle
•Ammonification/mineralization
•Nitrification
•Denitrification
•Nitrogen Fixation

37. •Plants die or bacterial cells lyse  release of organic
nitrogen
•Organic nitrogen is converted to inorganic nitrogen
(NH3)
•When pH<7.5, converted rapidly to NH4
•Example: Urea NH3 + 2 CO2
Ammonification

38. Ammonification
_____________________ - After all the living
organisms have used the ___________________,
decomposer bacteria convert the nitrogen to
_______________.
N
H
H
H
Ammonification
organic nitrogen
ammonia
Bacteria Ammonia
Organic Nitrogen (proteins)

39. Nitrification
Two step reactions that occur together :
•1st step catalyzed by Nitrosomonas
2 NH4
+ + 3 O2  2 NO2
- +2 H2O+ 4 H+
•2nd step catalyzed by Nitrobacter
•2 NO2
-
+ O2  2 NO3
-

40. Nitrification
_______________ is the process that
converts ammonia (NH3) into nitrites
(NO2) and nitrates (NO3) which ____
plants _______ use.
Note: Ammonia comes from ______
nitrogen fixation and ammonification
How is it done?
_____________________ N
N
N
H
H
H
O O
O
O O
Nitrification
most
can
Both
Bacteria!

41. Denitrification
•Removes a limiting nutrient from the environment
•4NO3
-
+ C6H12O6 2N2 + 6 H20
•Inhibited by O2
•Not inhibited by ammonia
•Microbial reaction
•Nitrate is the terminal electron acceptor

42. Denitrification
_______________: Process in which nitrogen
compounds _____________________ into
atmospheric nitrogen (N2 or N2O).
The main process is performed by
_____________________ in the soil. It can also
happen by _____________ fossil fuels.
N2ONO3
N2
Denitrification
convert back
bacteria
burning

43. Nitrogen Fixation
___________________ is the process in
which the N2 compound in the atmosphere
breaks and combines with other compounds.
The nitrogen is _________ when it combines
with ______________ or _______________.
N
N
H
N
HH
N2
Nitrogen Fixation
“fixed”
hydrogen oxygen
Ammonia (NH3) Nitrous Oxide (N2O)

44. Three ways to “fix” Nitrogen
Main process: Special ____________
convert the nitrogen gas (N2) to ammonia (NH3),
which only ________ plants can use (peas, beans).
_________________ strikes convert N2 to N2O
or NO3.
Industrial production. ____________
manipulation turns N2 into NH3 (Fertilizer)
bacteria
some
Lightning
Chemical

45. Human Impact
___________________, releases toxic nitrogen compounds
into the atmosphere.
____________________________ release nitrous oxide into
the atmosphere and introduce excess nitrogen into the
environment.
Remove nitrogen from the soil when we mine it for nitrogen
rich __________________________.
Discharge of ___________________________ releases
excess nitrogen into the water ecosystems which disrupts the
aquatic balance and kills fish.
Combustion
Commercial Fertilizers
mineral deposits
municipal sewage

46. Hydrological cycle

48. What is the Hydrological Cycle?
The hydrological cycle is the system which describes the
distribution and movement of water between the earth and its
atmosphere. The model involves the continual circulation of water
between the oceans, the atmosphere, vegetation and land.

49. Describing the Cycle:
•Evaporation
Solar energy powers the
cycle. Heat energy from the
sun causes evaporation
from water surfaces (rivers,
lakes and oceans) and….

50. • … transpiration from plants.
Transpiration is essentially
evaporation of water from plant
leaves.
• Evapotranspiration – water loss
to the atmosphere from plants
and water surfaces.

51. Condensation
The warm, moist air (containing
water vapour) rises and, as it
cools, condensation takes place to
form clouds.

52. Precipitation
•…precipitation
occurs, either as rain
or snow depending
on altitude.

53. Run off / Overland flow
• The rainwater flows,
either over the ground
(run off) into rivers
and back to the ocean,
or…

54. Groundwater flow
•… infiltrates downwards
through the soil and rocks
where it is returned to the
oceans through
groundwater flow.

55. Groundwater flow