CONCEPTS OF BIOSPHERE AND

TROPHIC CHAINS.

BY: HERMAN NDJAMENGROUP: 205

CONTENTS• CONCEPT OF BIOSPHERE AND IT’S

STRUCTURE• ECOSYSTEM AND IT’S TYPES• PARAMETERS OF AN ECOSYSTEM• ECOLOGICAL OPTIMUM, PESSIMUM,

SPECTRUM AND VALENCYTROPHIC CHACONTENTS• CONCEPT OF BIOSPHERE AND IT’S

STRUCTURE• ECOSYSTEM AND IT’S TYPES• PARAMETERS INS AND THEIR

IMPORTANCE

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 10kmHYDROSPHERE: Represents the liquid component up to a depth of 12km

ECOSYSTEMDEFINITION 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

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.

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

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

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.

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

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,

THANKS FOR YOUR ATTENTION

THE END