Ecosystem

Ecosystem
by
M.Shanmugaraj
Lecturer / Civil
V.S.V.N.Polytechnic College, Virudhunagar
TamilNadu
India

1. Prepared by
M.ShanmugarajM.E.,
Lecturer / Civil Engineering
V.S.V.N Polytechnic College,
Virudhunagar
Tamil Nadu
India
ECOSYSTEM

2. Definition
Anecosystemis acommunityof living
organisms (plants, animals and microbes) in
conjunction with thenonliving componentsof
their environment (things like air, water and
mineral soil), interacting as a system.
An ecosystem is formed by the interactions
between all living and non-living things
The sum of all of the biological and non-
biological parts of an area that interact to cause
plants to grow and decay, soil or sediments to
form, and the chemistry of water to change
(Aber& Melillo2001)

4. Components of Ecosystem
An ecosystem consists of two main components
Abioticor Non-living components.
1. Inorganic substances
2. Organic compounds
3. Climatic factors
Biotic or Living components.
1. Autotrophsor Producers
2. Heterotrophsor Consumers
3. Decomposers or Saprotrophs

5. Abioticor Non-living components.
It includes the non living substances of the
environment eg. Water, Soil, Air, Light,
Temperature, Minerals, Climate, etc.

6. Biotic or Living components
The biotic factors include the living organisms of
the environment. Eg. Plants, Animals, Bcteria,
Viruses, etc.,

7. Ecosystem structure
Producers/autotrophs--normally plants
that capture the sun’s energy, powering all
other life on Earth (also chemosynthetic bact.)
Consumers/heterotrophs--must eat to get
food
Decomposer--bacterium, fungus, etc. feeds
on dead organisms from all trophic levels,
returning nutrients to the soil

8. Producers/Autotrophs
The organisms which carry out photosynthesis constitute
the Producers of an ecosystem. Eg. Plants, Algae and
Bacteria
The producers use inorganic substances of the abiotic
factors and convert them in to organic food materials.

9. Consumers or Heterotrophs
Consumers are organisms whish eat other
organisms. All animals are consumers.
They are further divided in to primary consumer,
secondary consumer, tertiary consumer

10. Types of Heterotrophs:
Saprophytes: include those
heterotrophic
plants, fungi, and bacteria
which
live on dead matter -AKA
decomposers
Herbivores: plant-eating animals
Carnivores: meat-eating animals
Omnivores: consume both plants
and meat

12. Reducer or Decomposer
These are organisms that break up the dead bodies
of plants, animals and their waste products.
They include fungi and certain bacteria
The enzyme secreted by the fungi and bacteria
digest the dead organisms and the debris in to
smaller bits or molecules.
Theses molecules are absorbed by the reducer and
release molecules to the environment as chemicals
used by the producers.

13. Food Chains and Webs:
If an ecosystem is to be self-sustaining it must
contain a flow of energy.
Those life activities that are characteristic of living
organisms require an expenditure of energy.
The pathways of energy through the living
components of an ecosystem are represented by
food chains and food webs.

14. Producersconvert the radiant energy of the sun
into the chemical energy of food.

15. A.Food chain: involves the transfer of energy from
green plants through a series of organisms with
repeated stages of eating and being eaten
B. Food web: In a natural community, the flow of
energy and materials is much more complicated
than illustrated by any one food chain.

16. Food Chain

17. Food Chain

18. Since practically all organisms may be consumed by more
than one species, many interactionsoccur along the food
chains of any community.

19. Food Web Interactions:
Producers: (plants) –the energy of the community is derived
from the organic compounds in plants -(grass in the web
above)

20. Primary Consumer: (always a herbivore) -feeds on plants
(mice, grasshoppers,andrabbits in the web above)

21. Secondary Consumer: (always a carnivore) --feeds upon other
consumers (frogs, sparrows, snakes, and foxes above)
Omnivores may be primary or secondary consumers.

22. Decomposers: break down organic wastes and dead organisms to
simpler substances (ex. bacteria of decay)
** Through decomposition, chemical substances are returned to
the environment where they can be used by other living
organisms.

23. Energy Flow:
Energy flows through ecosystems in one
direction, typically from the Sun, through
photosynthetic organisms, including green plants
and algae, through herbivores, to carnivores, and
finally decomposers.

25. Energy Flow

26. There is a decrease in the overall energyin
each level as you move up the food web.
This means that there is much moreenergy in
the producer level in a food web than at the
consumer levels.
Also, this means that there is moreenergy at
the primary consumer level than at the
secondary consumer level.

27. Energy Transfer:
Each consumer level of the food pyramid utilizes
approximately 10% of its ingested nutrients to build new
tissue.
This new tissue represents foodfor the next feeding level.
The remaining energy is lostin the form of heat and
unavailable chemical energy. Eventually, the energy in an
ecosystem is lost and is radiated from the earth.
Thus, an ecosystem can not survive without the constant
input of energy from the sun.

28. Ecological Pyramid
The energy of organisms gradually decrease from the
producer level to the consumer level.
This can be represented in the form of a pyramid called
Ecological Pyramid
Graphical representation of the energy of the successive
trophic levels of an ecosystem.
It was first described by Charles Elton in 1927

29. In the ecological pyramid, the producer forms the base and
the final consumer occupies the apex
Types of ecological pyramid
1. The pyramid of number
2. The pyramid of biomass
3. The pyramid of energy

30. Inverted Pyramid
In some ecosystems, the number and the biomass of the
producers are less and those of consumers are more.
This type of ecosystem produces a pyramid where the apex is
directed downwards.
This type of pyramid is called Inverted Pyramid

31. Types of Ecosystem
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.

32. Marine Ecosystem:
It includes saline water ecosystems like
oceans, seas, estuaries etc.,
LimnicEcosystem:
It includes all freshwater ecosystems like
ponds, pools, lakes, rivers, streams etc.,
Terrestrial Ecosystem:
It includes the ecosystems of air, forests,
grass lands, deserts, etc.,
Artificial Ecosystem:
These are man made ecosystems of air, forests,
grasslands, deserts, etc.,

33. Pond Ecosystem
A pond is a suitable example for aquatic ecosystem.
The pond ecosystem is formed of abiotic factors and
biotic factors
The abiotic factors of the pond ecosystem are water,
CO2, O2, inorganic compounds, organic compounds,
light, temperature, pressure, pH, etc.
The biotic factors of the pond ecosystem are plants and
animals

34. Pond Food Web

35. River Ecosystem
River ecosystems are prime examples of loticecosystems
Loticrefers to flowing water
It is a running water ecosystem
It has water current. Water is in motion
The major rivers of India are Ganga, Yamuna, Bramaputra,
Thungapatra, Cauveri, Vaigai, etc.
It is made up of two components, namely abiotic
components and biotic components
The abiotic components are the non-living factors such as
ricer, soil, water, light, temperature, etc.
The biotic components are the living factors

36. Lake Ecosystem
A lake is a large fresh water body of water which
has no connection with the sea.
It is a standing water body (Lentic)
It is of great depth
The lake is of three types, oligotrophic lake,
eutrophic lake and dystrophic lake.

37. Oligotrophic lakes are young lakes, they are deep, they are poor in
fauna and flora.
Eutrophic lakes are swallow. They are shallow but rich in fauna and
flora
Dystrophic lakes are swallow or deep. They are poor in fauna and flora

38. Marine Ecosystem
Marine ecosystem comprises the ocean and sea
Marine ecosystemsare among the largest of Earth'saquatic
ecosystems.
Marine waters cover two-thirds of the surface of the Earth
Marine ecosystem has a wealth of aquatic food
The marine ecosystem consists of abiotic factors and biotic factors

39. Marine Ecosystem

40. Estuarine Ecosystem
Estuary is the meeting place of Sea and River
It is a shallow water body where river water mixes with
the sea water
It is rich in nutrients, it is a salt water body
It is a good fishing ground for fish farmers
The Ectuarine ecosystem consists of abiotic factors and
biotic factors

41. Estuaries

43. Forest Ecosystem
It consists of large trees and thick vegetation
The forest is a terrestrial ecosystem

44. Forest food web

45. Desert Ecosystem
A desert is a landscape form or region that receives very little
precipitation.<250 mm per annum.
It covers 1/5
th
of earth’s land surface.
Most of the deserts are composed of sand (ergs) and rocky
surface (reg).
Temperature ranges from 50 degree C to nearly zero level
within a single day.
Plants and animals have different morphological and anatomical
modifications to reduce water loss from the body.
Vegetations known as ‘xerophytes’ have modifications like pulpy stem
to store water and wax covered thorny leaves to reduce transpiration.
The roots are very long to reach the water table.
Animals such as reptiles, rodents, wolves etc hide themselves in
daylight and come out at night.

47. Desert

48. Why should we care about Ecosystem
Ecosystem ecology provides a mechanistic basis for understanding the Earth
System
Ecosystems provide goods and services to society
Human activities are changing ecosystems (and therefore the Earth System)
When an ecosystem changes, such as a pond dries out, or a new
organism is introduced to the ecosystem, it affects the entire process,
from the organism's food supply to the nutrients and chemicals
available in the ecosystem.
Humans largely affect the biosphere, sometimes obviously, and other
times, obliviously. Pollution in the ocean or the cutting down of trees
for construction purposes can destroy an ecosystem and put organisms
in grave danger.