Ecosystem
● Ecosystem is the
commerce of living effects among themselves and with their girding terrain.
● There are two introductory ecosystems − terrestrial and
submarine.
Structure of Ecosystem
● The relations
between the various biotic and abiotic factors of an ecosystem lead to the
conservation of the ecosystem.
● Position is the
perpendicular distribution of the different species occupying the different
situations. For example, trees do at a higher position also shrubs.
● The various aspects taken into consideration to study the
functioning of ecosystem are
I.
Productivity
II.
Decomposition
III.
Energy flow
IV.
Nutrient cycling
E
3. Biodiversity and Conservation:
4. Environmental Issues:
Productivity
● A constant force
of sun is needed for the proper functioning of any ecosystem.
● The quantum of biomass produced per unit area over a time
period by plants during photosynthesis is defined as the primary productivity.
● It's expressed as
weight (g − 2) or energy (Kcal m − 2).
● Productivity can
be substantially divided into gross primary productivity (GPP) and net primary
productivity (NPP). GPP is the rate of product of organic matter during
photosynthesis.
NPP = GPP − Respiratory losses (R)
● Secondary productivity is defined as
the rate of conformation of new organic matter by consumers.
● Primary productivity depends upon
I.
type of plants species inhabiting a particular
area
II.
photosynthetic capacity of plants
III.
nutrient vacuity
● Annual net
productivity for whole biosphere is about 170 b tons of organic matter.
RELATED LINKS:
Decomposition
● It's the process of breakdown of complex organic matter
into inorganic substances similar as carbon dioxide, water, nutrients etc.
● Fragmentation − Breaking
down of debris (dead plants and beast remains, faecal matter) into lower
patches by detritivores (decomposers)
● Filtering ¬ Process by
which these inorganic matters enter the soil
● Catabolism − Process by
which debris is degraded into simpler inorganic substances by bacterial and
fungal enzymes.
● Humification
− Accumulation of humus in the soil. Humus is resistant to microbial
action and decomposes at an extremely slow rate. It acts as a force of
nutrients.
● Mineralization
− Process by which humus further degrades to release minerals into the
soil
● It's an oxygen
consuming process and is controlled by the chemical composition of debris and
climatic conditions.
ALSO CHECK:
Energy Flow
● Sun is the sole source of energy for all ecosystems on
the earth.
● Plants and other photosynthetic organisms use lower than
50 of the solar radiation known as the Photoynthetically active radiation (PAR).
● In an ecosystem, plants
are called producer sand all creatures depend upon the plants directly or
laterally for their food. Hence, they're known as consumers or heterotrophs.
● The consumers can
be further divided into primary consumers (herbivores), secondary consumers (primary
herbivores), and tertiary consumers ( secondary herbivores).
● Food chain −The energy inflow among thevarious
constituent creatures is known as the food chain.
● Food web −The connection of thevarious
food chains is called the food web.
● Trophic level − Every organism
occupies a specific position in their food chain known as the trophic position.
Ecosystem Notes PDF
DIFFERENT TYPES OF ECOSYSTEM: Ecosystem is an open system and material can exchange from one ecosystem to another ecosystem. For ex. Frog move from the pond to the land and vice-versa.
The ecosystem can be classified based on size, nature and duration;
(1) Nature : On the basis of nature, it can be natural or artificial. Natural Ecosystem: This ecosystem forms naturally without interference of human.
Example include are pond, river, forest, village, hill etc. Artificial Ecosystem:
This ecosystem is developed and mainted by human. Example include are flowerbed, backyard, aquarium etc.
(2) Duration: On the basis of duration, ecosystem can be classified as temporary or permanent.
Temporary ecosystem: it is short lived and man made or natural. Example include rain fed pond.
Permanent ecosystem: it is long lived and self supported natural ecosystem for very long period.
Example includes forest, river etc.
(3) Size: Ecosystem is classified as small or large ecosystem.
Small: it is small and also known as micro ecosystem. It can be temporary or permanent. For ex. Pond, flowerpot etc
Large: it is large in size and also known as macro ecosystem.
It is always permanent and mostly natural. For ex. Ocean, river, forest and desert.
● Standing crop −
Each trophic position contains a certain quantum of living material at a
certain time known as the standing crop.
● The number of
trophic situations in a food chain is confined since the energy transfer
follows the 10 percent law i.e., only 10 of the energy is transferred from a
lower trophic position to an advanced one.
Ecological
Pyramids
● The energy
relationship between the different trophic situations is represented by the
ecological pyramids
. ● Their base represents the directors or the first
trophic position while the apex represents the tertiary or top position
consumer.
● Ecological pyramids are of 3 types
○ Pyramid of number
○ Pyramid of biomass
○ Pyramid of energy
Pyramid of number
Ecosystem Class 12 NCERT
Pyramid of energy
● In utmost ecosystems, the three pyramids are upright
except in some cases
○ The pyramid of biomass is reversed in an ocean ecosystem
since a small standing crop of phytoplankton supports a large number of
zooplankton.
○ The pyramid of number can be reversed when, say, a large
tree is eaten by small insects.
○ Still, the pyramid of energy is always upright.
● A trophic position
represents a functional position and not a single species as similar. Also, a
single species may come a part of further than one trophic position in the same
ecosystem at the same time depending upon the part it plays in the ecosystem.
● Limitations of
ecological pyramids
○ The ecological pyramids don't take into account the same
species belonging to further than one trophic position.
○ It assumes a simple food chain that nearly noway exists
in nature. It doesn't explain food webs.
○ Saprophytes aren't
given a place in ecological pyramids indeed though they play a vital part in
ecosystem.
Ecological
Succession
● The composition of all ecosystems keeps on changing with
change in their terrain. These changes eventually lead to the climax community.
● Climax community
− It's the community which is in equilibrium with its terrain. Gradational and
fairly predictable change in the species’ composition of a given area is called
ecological Succession .
● Sere (s) −
It's the sequence of communities that consecutively change in a given terrain.
The transitional communities are called seral stages or seral communities.
● Succession happens in areas where no life forms ever was
as in bare Rocks, cool lava,etc. (
primary Succession ), or in areas which have lost all life forms due to
destructions and cataracts ( secondary Succession
).
● Primary Succession
takes hundreds to thousands of times as developing soil on bare Rocks is a slow
process. Secondary Succession is faster than primary Succession since the nature doesn't have to start from
scrape.
● During Succession, any disturbances (natural/ man ¬ made)
can convert a particular seral stage to an earlier one.
● Hydrarch Succession
− It takes place in wet areas and converts hydric conditions to mesic.
● Xerarch Succession − It takes place in
dry areas and converts xeric conditions to mesic.
● Pioneer species − These are the species
that first foray a bare area. On land, these could be lichens that cache
enzymes to dissolve the gemstone shells for soil conformation while in water,
colonist species could be phytoplankton’s.
● The ultimate result of all relations is a climax
community, a mesic.
Nutrient
Cycling
● The quantum of nutrients present in the soil at a given
time is known as the standing state.
● Nutrients are
never lost from the ecosystem. They're only reclaimed from one state to
another.
● The movement of nutrients through the various factors of
the ecosystem is called nutrient cycling or biogeochemical cycles. They're of
two types
○ Gaseous −
Reservoir for these types of cycles live in the atmosphere.
○ Sedimentary −
Reservoir for these types of cycles live in the earth’s crust.
Carbon
Cycle
● About 49 of the dry weight of living organisms is made up
of carbon.
● The ocean reserves
and fossil energies regulate the quantum of CO2 in the atmosphere.
● Plants absorb CO2
from the atmosphere for photosynthesis, of which a certain quantum is released
back through respiratory conditioning.
● A major quantum of
CO2 is contributed by the decomposers who contribute to the CO2 pool by
recycling dead and decaying matter
. ● The quantum of CO2 in the atmosphere has been increased
vastly by mortal conditioning similar as burning of fossil energies,
deforestation.
Phosphorus
Cycle
● Phosphorus is an
important element of cell membranes, nucleic acids, and cellular energy
transfer systems.
● Rocks contain
phosphorus in the form of phosphate.
● When Rocks are
survived, some of the phosphate gets dissolved in the soil result and is
absorbed by plants.
● The consumers get
their phosphorus from the plants.
● Phosphorus returns
back to the soil by the action of phosphate-solubilizing bacteria on dead
organisms.
