Ecological concepts, Food chains

1. CONCEPTS OF
BIOSPHERE AND
TROPHIC CHAINS.
BY: HERMAN NDJAMEN
GROUP: 205

2. CONTENTS
• CONCEPT OF BIOSPHERE AND IT’S
STRUCTURE
• ECOSYSTEM AND IT’S TYPES
• PARAMETERS OF AN ECOSYSTEM
• ECOLOGICAL OPTIMUM, PESSIMUM,
SPECTRUM AND VALENCY
TROPHIC CHACONTENTS
• CONCEPT OF BIOSPHERE AND IT’S
STRUCTURE
• ECOSYSTEM AND IT’S TYPES
• PARAMETERS INS AND THEIR

3. BIOSPHERE
DEFINITION: The biosphere is the global sum
of all ecosystems. It is regarded as the zone of
life on Earth, a closed and self-regulating system.
components of the biosphere include:
TROPOSPHERE: It represents the a surface layer
of the atmosphere which extends up to a height
of 25km.
LITHOSPHERE: It represents the component of
the ground up to a depth of 10km
HYDROSPHERE: Represents the liquid component
up to a depth of 12km

4. ECOSYSTEM
DEFINITION
An ecosystem is a set of organisms interacting with each other,
as well as with the environment in which they live. It involves all
interaction between living and non living components of the
biosphere.
TYPES OF ECOSYSTEMS
MICROECOSYSTEM: it involves small streams and glades
MESOECOSYSTEM: Represent sea, pond wood and river.
MACROECOSYSTEM: It involves oceans and continents
GLOBAL ECOSYSTEM: Represents the Biosphere as a whole

5. PARAMETERS OF ECOSYSTEM
QUALITATIVE: It represents the variety of species of an
ecosystem i.e all the different species of living organisms present in
an ecosystem.
QUANTITAVE: It represents the number of a given specie of an
organism in the ecosystem.
A change in any of the above parameters causes a disbalance
in the stability of the ecosystem which can become a very important
condition to human life with time. The factors that disrupt these
parameters are of various kinds.
A set of ecological factors that help to provide the normal vital
activity(parameters) of a given kind of organisms is called an
ECOLOGICAL NICHE.

6. ECOLOGICAL OPTIMUM, PESSIMUM,
SPECTRUM AND VALENCY
ECOLOGICAL OPTIMUM
The zone of ecological optimum is a range of values of
ecological factor optimal for vital activity of the given species.
The law of ecological optimum explains that; the vital
activities of organisms and their conditions of life depend on different
factors of the environment.
ECOLOGICAL PESSIMUM
These are zones of suppression of vital activity. They are
generally found above or below the value of an ecological factor.
ECOLOGICAL SPECTRUM.
The ecological spectrum of species is a set of ecological
valencies on different ecological factors. Due to ecological spectrum,
species can be classified into eurybiontic; having a wide spectrum
and stenobiontic; having a narrow spectrum.
ECOLOGICAL VALENCY.
This represents the range zone of optimum for each ecological
factor for a given specie of organisms

7. TROPHIC CHAINS
The trophic chain is a chain of transmission of energy or
substances from low-organized to a high-organized organisms in an
ecosystem.
Every trophic chain is composed of 4 levels which include:
PRODUCERS: This represent organisms which are able to
manufacture their own food. A classical example of organisms falling
in this group are plants.
PRIMARY CONSUMERS: They feed on producers and are
hence herbivorous organisms. An example is a Goat.
SECONDARY CONSUMERS: They can either be omnivorous or
carnivorous because they feed on both producers and primary
consumers or producers respectively. Example lion and Man,
DECOMPOSERS: These organisms feed exclusively on dead
organic matter of plants and animals

8. TYPES OF TROPHIC CHAINS
There are basically two types of trophic chains:
1. DIRECT FOOD CHAIN.
This is a direct feeding relationship between all levels of the
trophic chain in which each organism has a single source of food.
EXAMPLE
GRASS SHEEP MAN FUNGI
(producer) (primary consumer) (secondary consumer) (Decomposer)
The stability of this trophic chain can easily be disrupted if one of
the organisms is lacking.

9. 2. FOOD WEB
This is a trophic chain in which organisms do not have only a single source
of food. It is more stable than the food chain.
EXAMPLE

10. IMPORTANCE OF TROPHIC CHAINS
1. They form an important component of the ecosystem.
2. Producers are important sources of food in an ecosystem.
3. The organisms in an ecosystem help to keep a balance
between all the gases released in the atmosphere.
4. They also protect the ozone layer by reducing the amount of
greenhouse gases released to the atmosphere.
5. Other organisms reduce the degree of water pollution which
could be very risky for man,

11. THANKS FOR YOUR
ATTENTION
THE END