Ecosystem Concepts

1. Presented by

2. Concepts of Ecology
Definition
Ecology is the scientific study of
interaction between living systems and their
environment
Objective
Ecology discovers and understands the
relationship between living things and their
environment

3. Hilaire, 1835 -Milieu ambient (French)
Haeckel, 1866 – Science associated with life
Elton, 1927 – Scientific natural history
Shelford, 1929 – Science of communities
Andrewartha, 1961 – Study of the distribution
and abundance of
organisms
Odum, 1963 – Study of structure and
functions of
nature
More Definitions

4. Ecologist
A person who studies ecology
e.g., Plant ecologist, Animal
ecologist, Terrestrial / Aquatic
ecologist,
Palaeo-ecologist,
Mathematical ecologist, Systems
ecologist,
Chemical ecologist, Social
ecologist, Anthropo-ecologist,
Autecologist,
Synecologist.

5. TEN RULES IN ECOLOGY
• Ecology is a Science.
3. Ecology is only understandable in the light of
evolution.
5. Nothing happens ‘for the good of the species’.
7. Genes and environment are both important.
9. Understanding complexity requires models.
11. ‘Story telling’ is dangerous.
13. There are hierarchies of explanations.
15. There are multiple constraints on organisms.
17. Chance is important.
10. The boundaries of physical environment are in the
mind of the Ecologist.

6. Branches of Ecology
Habitat ecology Desert ecology
Grassland ecology
Freshwater ecology
Forest ecology
Cropland ecology
Marine ecology
Population ecology
Community ecology
Ecosystem ecology
Production ecology
Conservation ecology
Radiation ecology
Palaeoecology
Gene ecology
Systems ecology
Microbial ecology

7. Concept of EnvironmentConcept of Environment
Definition
 The total surrounding of an organism.
 Environment is an interacting system of physical, chemical,
biological social and cultural elements.
Attributes
1.Environmental systems usually do not have well defined boundaries.
2.Environmental characteristics change over a gradient.
3.Environmental system is open because it receives inputs from and
gives outputs to other systems.
4.Environment ultimately determines the quality and survival of life.

8. Lithosphere
- Solid earth
Divisions
Environment
Physical environment Biotic environment
Hydrosphere Atmosphere
- Water
- Gaseous
envelope
Biosphere
Flora
Fauna
- Plants, microbes
Animals

9. Ecological System Concept
(Concept of Ecosystem)
Ecosystem is the basic structural andEcosystem is the basic structural and
functional unit of ecology.functional unit of ecology.
“Ecosystems are the basic units of
nature
on the face of the earth”.
An ecosystem is an ecological unit, or a
subdivision of the landscape, or a geographic area that
is relatively homogeneous and reasonably distinct from
adjacent areas.
J.W. Marr, 1961
Tansley, 1935
Definition

10. Ecosystem – another view
•Ecosystem is a spatial functional structure
•The space may be geographically large or
small
•Largest ecosystem. e.g., Planet earth
•Smallest ecosystem (microcosm):
•e.g. a handful of soil and moss in a sealed
jar.

11. Components of an Ecosystem
Abiotic components-
(geographical, climatic, (geographical, climatic,
physicochemical characteristics)physicochemical characteristics)
Biotic
components-
(Plants, animals, microbes) (Plants, animals, microbes)

12. Ecological Cycle

13. Ecosystem Structure

14. ¨
Living organisms and their
non-living environment
are inseparable,
interrelated and interact upon
each other.
Interactions between Organisms
and Environment

15. Mountain ecosystem – Removal of forest cover
Evergreen forests – Over exploitation of forest resources
Coral reefs – Human interference, Dynamite fishing
River ecosystem – Pollution
Land ecosystem – Dumping solid wastes
Specific influence of human
beings on sensitive Ecosystems

16. Properties of Ecological
Systems
1.Networks –Interdependence, diversity,
complexity
2.Boundaries- Scale and limits
3.Cycles – Recycling of resources and
partnership
4.Flow –through – Energy and resources
5.Development – Succession and co-evolution
6.Dynamic balance- Self – organization,
flexibility, stability, sustainability

17. Systems BiologySystems Biology
A biology that sees an organism as a living
system rather than a machine.
Systems theory
It looks at the world in terms of the
interrelatedness and interdependence of
all phenomena.
Systems thinking is process thinking
System defined
A system is an object that is made up of
subsystems or components, which interact in such a
way that they have collectively a wholeness.

18. Salient features of system concept
1. There is a collection of elements (subsystems) in a system.
2. The components (subsystems) and their processes are
organized.
5.The interactions between the subsystems are
repeated in time and space.
4. There is unidirectional flow of energy and matter.
●
A healthy system is self-regulating based upon A healthy system is self-regulating based upon
the feed-back control from subsystems.the feed-back control from subsystems.
Examples : Animal social systems – An Ant hill, a bee hive,
a termite mound.
Human social systems – a family.

19. SystemSystem
InputsInputs
OutputsOutputs
Simple System ModelSimple System Model

20. System
Feedback
 A cybernetic system is a collection of parts or events that acts as a single
thing and regulates its activities about an ideal state or set point
 Cybernetic systems use feedback to maintain this ideal state.
 The feedback that causes the adjustment to the set point is called negative
feedback.
 Cybernetic systems can also display positive feedback.
 Positive feedback is a continually increasing tendency away from the
system’s set point.

21. Systems Concept
 A system consists of a set of interdependent subsystems
enclosed in a defined boundary.
 A system receives inputs and outputs.
 An input is any resource from outside to which the system
responds.
 An output is any attribute transmitted to the environment.
 A system has feed back mechanism, which provides a degree of
control (or homeostasis)

22. Positive feedback
Set point
Negative
feedback
Deficiency
Excess
Negative
feedback
Death
Positive feedback
Death
Homeostatic Plateau
A Cybernetic system of
Ecosystem Regulation

23. Systems Concept
Nutrients
Gases
H
2
O

Radiant
Energy
Nutrients
Gases
H
2
O
Bio-systems
Producers ® consumers
Decomposers
(Cycling of energy and
matter)
Outputs
Inputs

24. Biotic
component
1
Biotic
component
2
Biotic
component 3
Input
Output
Ecosystem
Output
Input
Output
Input
Output
Nutrient Flow model

25. System X Y Z
Subsystem
X
Subsystem
Y
Subsystem
Z
Inputs Outputs
Open system with components

26. Plant Cow Man
Input
Sunlight
Output - Input
Chemical
energy in
leaves
Output - input
Chemical
energy
in meat
of cow
Output
Heat
given
off during
Series open system components

27. Features of an open systemFeatures of an open system
Open systems process inputs and produce
outputs
The amount of output produced is directly
related to the amount of input received.

28. Features of Complex systems
•Complex systems are composed of many
interconnected and interacting subunits.
•They are capable of adaptation and self-
organization.

29. Open systems
All living systems are open systems.
A cell is an open system because it
constantly acquires food from outside
itself and eliminates wastes.
It gives off heat as it carries on
chemical processes (respiration).

30. Biological SystemsBiological Systems
Hierarchical SystemHierarchical System
Genetic systems
Cell systems
Organ systems
Organismic systems
Population systems
Ecosystems

31. Dynamics of ecosystems
Bio-systems
Energy,
Gases
inorganic
matter
water
organisms
Subsystems
Plants ® animals
Microbes
Energy
Nutrients
Gases
Inorganic
matter
Inputs Outputs

32. Gaseous
Nutrient cycles
Sedimentary
nutrient cycles
Biogeochemical cycles and population
– Evolution spiral
Outputs
Heat radiated
into space
Inputs
Sunlight
(energy)
The earth as a single system
Earth Ecosystem

34. Functional aspects
Inputs
Energy,
Nutrients,
Gases,
Inorganic
matter
Photosynthesis
Herbivory
Carnivory
Decomposition
Energy
Nutrients
Gases,
Inorganic
matter
Outputs
Biosystems

35. Solar energy
Photosynthesis
Solar energy is converted to chemical energy
Respiration
Chemical energy is used to do work
Ecosystem
Degraded Waste Energy
Energy flow in an Ecosystem

36. Primary ProductionPrimary Production
Phototrophs (Plants) – The rate of photosynthesis
per unit of time.
Gross Production – Quantity of organic matter produced
per unit of time.
Net Production – Gross P – metabolic losses (respiration,
excretion)
Secondary ProductionSecondary Production
All biomass produced per unit of time by organisms
called consumers.

37. Primary and Secondary Production
 Primary – Rate of photo synthesis by green plants.
 Secondary – The energy stored at consumer level for
use.
Ecological succession
Progressive changes in community structure and
function.
Ecosystem Regulation
The ecosystem tries to resist change
and maintain itself in equilibrium is called
Homeostasis.

38. Production
(Stored biomass)
Gross Production
Producers Photosynthetic
Production
Secondary
Production
RespirationDecomposers
Consumers
and
Decomposers
Respiration Tissue growth
Respiration Tissue growth
Relationship between plant and Relationship between plant and
animal productionanimal production

40. Properties of Bio-systemsProperties of Bio-systems
1.It is intrinsically dynamic, flexible, open systems.
3.There is cyclical patterns of information flow.
5.The structure and function are established by the system itself
(self-organising system).
7.It exhibits a certain degree of autonomy.
9.There is self-transformation and self-transcendence.
11.It has a high degree of stability (Homeostasis).
13.There is a state of continual fluctuations within limits.
15.It has the ability to adapt to changing environment.
17.It exhibits self-maintenance which includes the processes of self-
renewal, healing, homeostasis and adaptation.

41. 1.Energy cycles – Ecological pyramids
2.Food chains, food webs and trophic
structure
3.Diversity of organisms – Variety and
variability.
4.Nutrient cycles – biogeochemical cycle e.g.
Water cycle, Carbon cycle, Oxygen cycle,
Nitrogen cycle.
5. Ecosystem development and regulation.
Functional aspects of Bio-systems

42. Direct values
Consumptive use value – Non-market value
of fruits, fodder, firewood, small timber
etc.
(People collect them from their surrounds and use
them)
Productive use value – Commercial value of
timber, fish, medicinal plants etc.
(People collect for sale)
Ecosystem goods and services

43. Indirect values
•Non-consumptive use value – Scientific research,
watching wildlife, ecotourism, jungle safaris etc.
•Option value – Maintaining options for the future –
Preserving and reaping the economic benefits in
the future.
•Existence value – Ethical and emotional aspects of
the existence of wildlife and nature.

44. Ecological Pyramids
Pyramid of numbers:
No of individuals at each trophic level
Graphic representation of tropic structure and
function of an ecosystem.
Hawks
Hyperparasites (microbes)
Frogs
Parasites (Lice, bugs)
Insects
Birds
Grasses
Trees

45. Pyramid of biomass:
Total biomass (dry matter) at each tropic level
Fox
Rabbit
Herbs
Pyramid of energy:
Amount of energy present at each trophic level.
Top Carnivores
Carnivores
Herbivores
Producers

46. Energy relationshipEnergy relationship

47. Energy cycleEnergy cycle

48. Nutrient cycling

49. Cycling of DDT

50.  At every trophic level there is 90% loss of energy (respiration, activity).
 Only 10% energy is transferred from one trophic level to the other.
 There is one-way flow of energy.
Nutrient Cycling
Nutrients like C, N, S, O, H, P etc.
Move in circular paths.
Hydrological cycle
Nitrogen cycle
Carbon cycle
Phosphorous cycle
Energy flow in an ecosystem

51. Hydrologic cycling

52. Biogeochemical Cycling

53. Functional Attributes
Food chains
The sequence of feeding relationships in
an ecosystem is called food chain.
Trophic structure
Each organism in the ecosystem is
assigned a feed level or trophic level.

54. Simple food web model
Producer : Pond grass
Herbivore : Water insects
Carnivore : Large fish
Herbivore : Small fish
Carnivore : Duck
Top Carnivore : Man

55. Sunlight
Producer
Carnivore
Herbivore
Heat
Produced
Decomposers
Simple Food – Chain Model

56. Kinds of food chain
• Grazing food chain – Starts with green plants and ends with
carnivores.
Grass ® Rabbit® Fox
2. Detritus food chain – Starts with dead organic matter and
ends with predators.
Mangrove ecosystem
Leaf litter ®Saprotrophs / detritivores (crabs) ®Small carnivorous fish ®
Large Carnivorous fish
- a complex inter connected network of food chains
at different trophic levels.
Food web

57. Significance of food chain
1.Food chains maintain energy flow and nutrient cycling.
2.Food chains maintain ecological balance by regulating
population size.
3.Food chains biologically magnify toxicity of some
chemicals.

58. Kinds of Ecosystems
Ecosystem
Terrestrial
Aquatic
Man-engineered
e.g. Forest, Desert
Grassland, Steppe,
Savanna
e.g. Agricultural land use,
Urban / industrial land use
Freshwater
Marine
Lentic
Lotic
e.g. Ponds,
Lakes
e.g. Streams,
Rivers
Coastal ecosystems
Mangrove ecosystems
Seagrass ecosystems
Coastal lagoon ecosystems
Coral reef ecosystems
Delta ecosystems
Estuarine ecosystems
Sandy beach ecosystems
Rockyshore ecosystems
Coastal upwelling
ecosystems

59. Ecosystems

60. Forest EcosystemForest Ecosystem
1. 1. Abiotic ComponentAbiotic Component
Amount of rainfall and local temperature
varies according to latitude, and altitude.
2. 2. Biotic ComponentBiotic Component
Plants – trees, shrubs, climbers
and ground cover.
Animals – mammals, birds, reptiles amphibians, fish
insects and microscopic animals.

61. Kinds of Forests
•Coniferous
e.g. Himalayan region -needle –like leave forests.
•Tropical rain forests
e.g. Western Ghats –broad–leaved forest.
• Deciduous forests – e.g. Teak trees
• Thorn forests – e.g. Semi – arid.
• Mangrove forests – e.g. River deltas.

62. Forest servicesForest services
 Natural forests control local climate and water
regimes.
 Forest vegetation helps recycle nutrients.
 Forest prevent erosion of soil.
 Forests control flow of water in streams and rivers.
 Forests absorb carbon dioxide and release oxygen
that we breathe.

63. Forest services
- cont’d
●
Forests maintain gene banks of wild relatives.
●
Forest supply food, fodder, medicine, timber,
poles and fuel wood as well as raw materials
for industry.
●
Forests and wilderness areas are valued as
sites of natural and cultural heritage as well as
education and recreation.
●
Ecotourism is a vital source of income for some
countries.

64. The Grassland ecosystemThe Grassland ecosystem
•Abiotic Components – C, H, O, N, P, S. are
supplied by Carbon dioxide, Nitrate, Phosphates and Sulphates.
2. Biotic Components
Producers – grasses, few herbs and shrubs.
Primary consumers – grassing animals- cows, deers, rabbit.
Secondary consumers – snake, lizard, birds, Jackels.
Tertiary consumers – hawks.
Decomposers – bacteria.

65. Desert ecosystemDesert ecosystem
1.Abiotic components – High temperature, low rainfall
dry climate.
2. Biotic components
Producers – Shrubs, bushes, grasses, few trees.
Consumers – Insects, reptiles, birds, camels.
Decomposers – Fungi, bacteria.

66. Aquatic ecosystem
1.Abiotic components – Temperature, light, pH, organic and
inorganic matter.
2.Biotic components
Producers – Macrophytes, Phytoplankton.
Consumers – Zooplankton (insects, fish),
Herbivores.
Decomposers – Bacteria, Fungi.

67. e.g. Industrial areas, Cities and Towns.
Urban Ecosystem
Ecosystems in which
man lives and works.
Control of man over land
ecosystem
 Approx 11 percent of earth’s land
surface is intensely managed.
 30 percent moderately managed.
 59 percent only slightly utilized.

68. General Features
Urban Ecosystem
1.Most intensively managed ecosystem by
man.
2.Approx. 20 percent of world population
lives in urban regions.
3.The city is an open ecosystem.
4.Inputs include air, water, energy (food,
fuel), natural resources, and people.
5.Outputs include products, waste,
garbage heat, people, ideas, education,
technology,
6.Numerous feedback loops or cycles.
Keep various city subsystems in balance.

69. Outputs

City Ecosystems
Inputs
Typical urban ecosystem
model

70. Ecosystem distress Syndrome
(Indicators of Ecosystem)
1.Altered primary production.
2.Altered rates of decomposition.
3.Altered rates of nutrient cycling.
4.Reduced efficiency of energy cycling.
5.Increased frequency of disease.
6.Changed amplitude of fluctuations.
7.Reduced species diversity.
8.Retrogression to opportunist / weedy /
pest species.
9.Size, enlargement in natural abiotic
zones.

71. Threats from Agricultural
Ecosystems
 Ecological simplicity – large
monocultures.
 Ecosystem instability.
 High degree of biological
uniformity (minimum genetic
variability).
 Widespread disease outbreaks or
pest infestations.
 Depletion of fertilizers
(nutrients) and energy (fossil
fuels).
 Elimination of other crop species
and other ecosystems.