Geography, SS 3, Week 4
Topic: Environmental Interaction
Contents:
- Definition of Environmental Interaction
- Spheres of the environment
- Definition of ecosystem
- Environmental balance
- Food chains and Food webs
- Interaction within the natural environment
- Effects of both natural and human interaction
Definition of Environment and Environmental Interaction
Environment is defined as the total surrounding or medium of any organism in a given area. This include physical surroundings, climatic factors and other living organisms in the surroundings.
Human Environmental Interactions can be defined as interactions between the human social system and (the “rest” of) the ecosystem.
Spheres of the Environment
The environment, which is the earth, is grouped into four sphere and these are
- Lithosphere: This is the solid portion of the environment which contain rocks, sand, soil minerals etc
- Hydrosphere: This is the liquid part of the environment like rivers, lakes and oceans
- Atmosphere: This is the gaseous portion of the environment where gases like oxygen, nitrogen, carbon dioxide etc are found
- Biosphere: This is the portion of the environment where plants and animals are found.
Definition of Ecosystem
Ecosystem is defined as the community of plants and animals living together in harmony an interacting with their physical environment. Ecosystem can also be defined s the relationship between organisms (plants and animals) and its physical environment.
Components of Ecosystem
There are two types of ecosystem which include:
(a) Abiotic component: this is the non living component of the ecosystem. It includes the factors or elements like soil, water, gases, sunlight etc
(b) Biotic component: this is the living component of the ecosystem. It includes plants and animals. The biotic component can be grouped into three sub – classes. These are:
(i) Autotrophs: these are called procedures. These green plants which can manufacture their own food from simple inorganic substances through the process of photosynthesis
(ii) Heterotrophs: these are also called primary and secondary consumers. These are organisms which cannot manufacture their own food e.g man, parasites, saprophytes etc
(iii) Decomposers: these are micro organisms that decompose dead organic matter in order to release nutrient required by the producers to prepare their food e.g fungi and bacteria
Meaning of Environmental Balance
Environmental Balance refers to the way of recycling, matter and the flow of energy within an ecosystem in order to ensure continuous supply or availability
Environmental balance is achieved through the following:
- Hydrological (water) cycle: Hydrological (water) cycle is the exchange or circulation of water between the oceans, the atmosphere and the land. The atmosphere receives the water through evaporation from ocean, rivers and from land.
- Carbon cycle: Carbon cycle involves the series of processes which contribute to the circulation of carbon in nature. Carbon is circulated in form of carbondioxide
- Mineral nutrient cycle: Mineral nutrient cycle refers circulation of mineral nutrient between plants and the soil. These mineral nutrient include mineral, calcium, iron, sodium, sulphur, potassium etc:
- Nitrogen cycle: Nitrogen cycle involves the complex process by which nitrogen is circulated between the atmosphere, soil, pant and animals. Plant can only use nitrogen in form of nitrate
- Food chain and food web
Food chain tropical level and food web
Food chain is defined as the linkage of a series of organisms in a habitat through the flow of energy of consumer levels and their nutritional sequence. Food chain also involves the transfer in which each organism feeds on one before it in a sequence. Example of food chain is as follow
Grass Sheep Man
Grass Grasshopper Toad Snake Hawk
Tropical level refers to the feeding stages found in a food chain example
Grass Grasshopper Toad Snake Hawk
1 2 3 4 5
The first in each group is usually called autotrophs (or producer) e.g grass, while the next e.g sheep is called the primary consumer while the last e.g man is called the secondary consumer.
The trophic level refers to the feeding stages found in a food chain
Food web
Food web is defined as the complex feeding relationship of an organisms made up of many interrelated food chains. It involves a wider range of energy transfer. The food web consist of five different food chains
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