Ecosystem structures deals about the Different Components of the Ecosystem, its dynamics and energy level.

1. ECOSYSTEM
STRUCTURE
Charilyn d. dela cruz

2. According to E.P.Odum, an American ecologist, an ecosystem is the
basic functional unit of organism and their environment interacting
with each other and with their own components.
An ecosystem includes all organisms that live in a particular place,
plus the abiotic environment in which they live - and with which
they interact – at that location.
ECOSYSTEM

7. ❶ The composition of biological community including species,
numbers, biomass, life history and distribution in space..
❷ The quantity and distribution of non living materials like
nutrients, water etc.
❸The range of condition for existence such as temperature, light
etc.
❹ The structure of ecosystem is characterized
by the organization of the biotic and
abiotic components.
STRUCTURE OF AN ECOSYSTEM

8. BIOTIC COMPONENTS

9. ABIOTIC COMPONENTS
Climatic
factors
Inorganic
substances
Organic
substances
Carbon cycle
Nitrogen cycle
Water cycle
Sunlight
Precipitation
Humidity
Wind action
Lipids
Proteins
Carbohydrates
Edaphic
factors
Soil
topography
minerals
soil

10. ABIOTIC COMPONENTS
A. Climatic Factors
Sunlight
precipitation
humidity
wind action

11. Inorganic Substance
These includes elements such as carbon, nitrogen, oxygen,
etc., used in the synthesis of complex substances and
involved in material cycle.
Example
Carbon Cycle
Nitrogen Cycle
Oxygen Cycle
Phosphorous

12. CARBON,THE BASIS OF ORGANIC COMPOUNDS , CYCLESTHROUGH
MOST ECOSYSTEM
 Carbon is a major constituent of
the bodies of organisms because
carbon atoms help form the
framework of all organic
compounds.
CO2 is the most significant carbon
containing compound in the
environment of organisms.
It makes up 0.03% of the volume
of the atmosphere.

13.  CO2 is taken up by plants during
photosynthesis.
 Animals eat the photosynthetic
organisms and build their own
tissues by making use of the carbon
atoms in the organic compounds
they ingest.
 Both photosynthetic organism and
animals obtain their energy by
breaking down some of the organic
compounds available to them.
 CO2 is released by organisms during
respiration and decomposition

14.  CO2 is also released by automobiles
and industries
 In aquatic ecosystem CO2 reacts
spontaneously with the water to
form bicarbonate ions (HNO3-)
which act as sources of carbon for
photosynthesis by algae and
aquatic plants.
 Methanogens, are microbes that
produce methane instead of CO2.
 Methane that enters the
atmosphere is oxidized to CO2 but
CH4 that remains isolated from
oxygen can persist for great lengths
of time.

15.  Burning of fossil fuel have
created imbalance in the
carbon cycle.
 Carbon that took million of
years to accumulate in fossil
fuels is being rapidly
returned on the atmosphere
thus contribute much on
global warming.

16. WATER CYCLE
Water is so crucial that changes in
its supply in an ecosystem can
radically alter the nature of an
ecosystem.
WATER CYCLE PROCESSES
Evaporation
Condensation
Precipitation
Run off
Percolation & Infiltration
Transpiration
Completion of cycle

17. • 78 % of the volume of
troposphere.
• Most complex cycle
• N2 gas can’t be used ‘as
is’ – it must be “fixed” so
that organisms can use
it
• STEPSTOTHE CYCLE
Nitrogen fixation
Assimilation
Ammonification
Nitrification
Denitrification

18. NITROGEN FIXATION
 Atmospheric Nitrogen must be processed, or “fixed” for plant use.
 Some fixation occurs through lightning strikes but most fixation if done by free
living or symbiotic bacteria
ASSIMILATION
 Plants get nitrogen from the soil, by absorption of their roots in the form of
either nitrate ions or ammonium ions.
AMMONIFICATION
 When a plant or animal dies, or an animal expels waste , initial form of nitrogen
is organic.
 Bacteria or fungi in some cases, convert the organic nitrogen within the remains
back into ammonium (NH4+) in the process called ammonification and
mineralization.

19. NITRIFICATION
 The conversion of ammonium to nitrate is
performed primarily by soil living bacteria and
other nitrifying bacteria.
 The oxidation of ammonium (NH4+) - is by
bacteria Nitrosomonas species
The nitrites by nitrobacteria
DENITRIFICATION
 The reduction of nitrates back into the largely
inert Nitrogen gas (N2) completing the Nitrogen
Cycle
 Is performed by bacterial species such as
pseudomonas and clostridium in anaerobic
conditions.
 They used the nitrate as an electron acceptor in
the place of oxygen during respiration.
NO3 —NO2 —N2O —N2

22. ORGANIC SUBTANCES
These includes lipids, proteins, carbohydrates
Which are formed by biotic components and that are linked with
biotic components.
They have strong influence on structure behavior and inter
relationship of various organisms in an ecosystem.

23. BIOTIC COMPONENTS
Producers
They are generally chlorophyll bearing autotrophic organisms
which prepare organic compounds from inorganic raw
materials.
Example
green plants and photosynthetic bacteria

24. a. Herbivore b. Carnivores
c. Omnivores d. decomposersCONSUMERS

25. FUNCTIONS OF AN ECOSYSTEM
Ecosystem have functional attributes
which keep the component parts running
together
For example – green leaves prepare food
and roots absorb nutrients from the soil.
Herbivores feed on part of the plant
production and in turn serve as food for
carnivores.
Decomposers carry out the function of
breaking down complex organic materials
into simple inorganic product which can
be used by the producers.
All these functions in an ecosystem occur
through delicately balanced and
controlled processes.

26. Food Chain, Food Web
& Ecological Pyramids

27. Food Chain
Flow of energy in an ecosystem is one way process. The
sequence of organism through which the energy flows, is
known as food chain.

28. •In a food chain each organism obtains energy from
the one at the level below.
•Plants are called producers because they create their
own food through photosynthesis
•Animals are consumers because they cannot create
their own food, they must eat plants or other animals
to get the energy that they need.
Key concepts

29. Tropic levels in a food chain
Producers
Consumers
(i) Primary consumers
(ii) Secondary consumers
(iii) Tertiary consumers
(iv) Quaternary consumers
Decomposers

30. Types of Food Chain
(i) Grazing Food Chain
•The consumers utilizing plants as their food , constitute
grazing food chain.
• This food chain begins from green plants and the
primary consumer is herbivore.
• Most of the ecosystem in nature follows this type of
food chain.
Ex: grass => grasshopper => birds => falcon

32. (ii) Detritus food chain
•This type of food chain starts from dead organic matter of
decaying animals and plant bodies to the micro-organisms
and then to detritus feeding organism and to other
predators.
•The food chain depends mainly on the influx of organic
matter produced in another system.
•The organism of the food chain includes algae, bacteria,
fungi, protozoa, insects, nematodes etc.

33. Detritus Food
Chain

34. •The knowledge of food chain helps in understanding
the feeding relationship as well as the interaction
between organism and ecosystem.
•It also help in understanding the mechanism of energy
flow and circulation of matter in ecosystem.
•It also helps to understand the movement of toxic
substance and the problem associated with biological
magnification in the ecosystem.
Significance of Food Chain

36. •A node represents an individual species, or a group of related
species or different stages of a single species.
• A link connects two nodes. Arrows represent links, and
always go from prey to predator.
• The lowest tropic level are called basal species.
• The highest tropic level are called top predators.
•Movement of nutrients is cyclic but of energy is unidirectional and
non-cyclic.
Key concepts

37. Types of food web representation
• These food webs simply indicate a
feeding relationship.
TOPOLOGICAL
WEBS
• Bio-energetic webs, or flow webs,
include information on the strength of
the feeding interaction.
FLOW WEBS
• In interaction the arrows show how
one group influences another.
INTERACTION
WEB

38. • Soil food web
• Aquatic food web
• Food web in forest
• Food web of grassland
• Food web in terrestrial and aquatic ecosystem
Different food webs

40. Aquatic food web

41. Food web in
forest

42. Food web of grassland
Grassland Food
Web

43. Food web in terrestrial and aquatic
ecosystem

44. •Food webs distinguish levels of producers and consumers by
identifying and defining the importance of animal relationships
and food sources, beginning with primary producers such as
plants, insects and herbivores.
•Food webs are important tools in understanding that plants are
the foundation of all ecosystems and food chains, sustaining life
by providing nourishment and oxygen needed for survival and
reproduction.
•The food web provide stability to the ecosystem.
Significance of Food Web

46. What are Ecological Pyramids?
•Ecological pyramids are
graphical representations
of the tropic structure
ecosystem.
•Tropic levels are the feeding
positions in a food chain
such as primary producers,
herbivores, primary
carnivore etc.

47. Types of Ecological Pyramid
Three types of ecological pyramids can usually be
distinguished namely:
• Pyramid of numbers
• Pyramid of biomass
• Pyramid of productivity

48. Pyramid of Numbers
•It is the graphic representation of number of
individuals per unit area of various tropic levels.
•Large number of producers tend to form the
base.
•Lower numbers of top carnivores occupy the tip

49. Pyramid
of
Numbers

51. Pyramid of biomass
•It is the graphical representation of biomass present
per unit area at different tropic levels, with
producers at the base and carnivores at the top.
•Biomass is calculated as
mass of each individual X no. of individual at tropic levels

53. Pyramid of productivity
•Pyramid of productivity is a graphical
representation of the flow of energy through
each tropic level of a food chain over a fixed
time period.
•The input of solar energy may be indicated by
adding an extra to the base.

54. Pyramid of
productivity

55. Disturbances in ecosystem
•Bioaccumulation - When plants / animals take up a chemical from the
environment and do not excrete it,the chemical builds up in the organism
over time to a potentially lethal level.
•Biomagnification - Refers to the sequence of processes that results
in higher concentrations of the chemical in organisms at higher levels in
the food chain. The concentration of the chemical may not affect lower
levels of the food chain but the top levels take in so much it can cause
disease or death.
•Extinction of species – Due to decrease in population of various species
the balance of various tropic levels is disturbed as a result some levels
have more accumulation of species while others have very less population.