Margdarshan
Environment is a broad concept. Physical, chemical and biological factors affecting
the living organisms in any possible way is collectively called as environment
There are two main types of environment. One is natural environment
and other is artificial environment
Natural environment consists of air, atmosphere, water, land, living organisms, etc.
Basically, environment consists of two basic factors- 1. Biotic factors,
2. Abiotic factors.
The science that deals with the study of interactions between biotic and abiotic factors of the environment is called as ecology
Basic functional unit used to study the ecology is called as ecosystem.
. Ecosystem is formed by biotic and abiotic components and their interactions with each other.
Components of Ecosystem :
The different components in the ecosystem are as follows:
Abiotic components : Air, water, soil, sunlight, temperature, humidity, etc.
Biotic components: All the types of living organisms, like bacteria, fungi, plants and animals.
Types of consumers : Primary, secondary, tertiary consumers or apex consumers are the different types of consumers in the ecosystem.
These types are classified according to the trophic level to which they belong.
Different trophic levels in food chain : The different trophic levels in food chain are
Producers (First trophic level),
Primary consumers (Second trophic level),
Secondary consumers (Third trophic level),
Tertiary consumers (Fourth trophic level) etc.
Q.What may be the relationship between lake and birds on tree?
Ans. The birds on the tree depend on the aquatic organisms in the lake for their feeding. Birds stay on the trees which are in the surrounding area of the lake, so that it is easier for them to capture fishes, frogs, etc. They must also be using the same lake water for drinking.
Food chain: In every ecosystem, there are always interactions between producers, consumers and decomposers. This sequence of feeding interactions is called food chain.
In every food chain there are links between four to five trophic levels constituting the producers, primary consumers, secondary consumers, tertiary consumers etc.
The links of food chain are in linear sequence.
Food web : Food web is the collection of many small food chains. Food web is complex network of many small food chains. Thus, when many food chains are interlinked, they form food web.
Ecosystem — A review : Biotic and abiotic factors and their interactions with each other form an ecosystem. Every element has important role to play for functioning of the ecosystem.
Plants are main producers of the ecosystem. Various herbivores like deer, goats, sheep, cattle, horses, camels, etc. feed upon producers.
Carnivorous predators e.g. lion and tiger control the population of the herbivores.
The decomposers and scavengers like caterpillars, termites, insects present in the dung carry out decomposition and thus clean the environment.
Existence of human beings is dependent on the balanced ecosystem.
. In the presence of sunlight, the green plants perform photosynthesis. Thus, they are producers of the food chain.
This food is consumed by the grasshopper. Thus, grasshopper is primary consumer.
Frog is secondary consumer as its diet consists of insects like grasshopper.
Snake is tertiary consumer as it feeds on frogs,
The hawk is apex consumer as it can kill the snake and feed on it.
Fungi shown in the picture of the food chain are acting as decomposers.
Few bacteria are shown in the picture act on all the levels and are bring about decomposition.
Q. What is necessary to convert this picture into food web? Why?
Ans. If this food chain has to be converted into a food web, there should be interactions between the different components. Any living organism can be victim to different predators. Moreover, a predator can also be a target for other. Frog eats different insects. The same frog can be either eaten by snake or by hawk.
Q. What will happen If fallen foliage in forest, dead trees, and Carcasses in and around villages had not been decomposed for years or not sent back to the nature.
Ans. Only by decomposition the semen and molecules trapped in the bodies of Organisms can be sent back to nature.
These Various components help in formation of the bodies of plants and animals.
If they are not sent back to nature, the cyclic flow of these elements will halt.
Only by the decomposition process, foliage in forest, dead trees, and carcasses are sent back to the nature.
If such decomposition halts for years, the entire earth will be covered by heaps of unwanted garbage. The entire balance of nature would be lost.
Margdarshan
Jivo Jivasya Jivanam : ‘Jivo Jivasya Jivanam’ is a Sanskrit saying which means that one living organism makes the living of the other or one living thing is the food of another
All the food chains occurring in the nature, function on this principle.
Prey and predator interactions are based on the above concept.
Example of a lion, deer and grass, the lion eats the deer, the deer eats the grass and when the lion dies it is converted into nutrients for soil which is consumed by grass.
Energy pyramid : Energy pyramid is the diagrammatic representation, that depicts the energy levels at the various trophic levels.
There are interactions in the form of energy transfer in all the food chains and food web. The energy pyramid shows how energy travels up a food chain.
Q. A bird building nest on a tree feed upon the fishes in a nearby pond. Whether this bird is part of both i.e. tree as well as pond ecosystem?
Ans. The bird is a part of both the ecosystems. For shelter, the bird builds nest on the tree. That means it takes advantage of tree ecosystem (terrestrial ecosystem). Moreover, it feeds on the fish from the pond. Being a predator, the bird maintains the fish population of the pond and thus it also becomes the part of the pond ecosystem too.
Ecosystem chart :
In South India in various places there is ⇒Paddy cultivation on a large scale ⇒Frequent attack of the grasshoppers on fields ⇒Predator frogs in large numbers ⇒Snakes to feed on the frogs ⇒
If frog population declines suddenly ⇒
Q. If frog population declines all of a sudden, What will be the effect on paddy crop?
Ans. If the population of frog declines, then there will be rise in the population of grasshoppers. The paddy fields will hence be infested with insect pests.
Q. Number of which consumers will decline and which will increase?
Ans. The food chain if altered, results in imbalance in the ecosystem. ‘Paddy ⇒ Grasshoppers ⇒ Frog ⇒ Snake’, this food chain is natural.
When by any reason there is decline in the number of frogs, thus secondary consumer will decline.
Due to this decline, snake which is at tertiary consumer level will also decline.
The primary consumers i.e. grasshoppers. Will increase as there is now no check on their population.
Due to increase in their population the paddy production will be reduced.
Due to reduced number of snakes, rats and other rodents from neighbouring areas would also rise, which are also secondary consumers.
Q. What will be overall effect on that ecosystem?
Ans. If frogs’ population declines, there would be imbalance of entire ecosystem. The number of prey and predator populations will change and thus the food chain will come to an end.
Margdarshan
Environment : Everything that is around a living organism is called environment.
Environment includes physical, chemical and other natural factors which surround the living organism.
Relationship between Environment and Ecosystem :
Environment is the collective term for physical, chemical and biological factors that surround the living organisms.
Many biotic, abiotic, natural and artificial factors together constitute conditions of the environment.
Two main types of environment :
(1) Natural environment : Air, atmosphere, water, land, living organisms, etc.
(2) Anthropogenic/Manmade/ Artificial environment.
Two main factors in environment :
(1) Biotic factors (2) Abiotic factors.
Continuous interactions occur between all the factors in the environment.
Artificial environment, directly or indirectly affects the natural environment.
Ecology : Ecology is the science that deals with the study of interactions between biotic and abiotic factors of the environment
Ecosystem : Ecosystem is the basic functional unit used to study the ecology.
Many ecosystems together form an environment.
Ecosystems constitute biotic and abiotic factors occupying a definite geographical area and their interactions.
Cycles operated in environment : In environment there are ‘bio-geo-chemical’ cycles.
These are of two types, viz.
Gaseous cycles e.g. nitrogen cycle, oxygen cycle, etc.
Sedimentary cycles e.g. phosphorus cycle.
Importance of bio-geo-chemical cycle :
(1) Plants require water, CO2, phosphorus, potassium, nitrogen, etc. as nutrients while animals require, carbohydrates, proteins, fats, etc. as nutrients.
(2) Producers and consumers after their death undergo decomposition and release elements which mix with the soil.
(3) The cyclic movement of nutrients is possible through bio-geochemical cycle.
(4) The cyclic movement of elements like carbon, nitrogen, phosphorus, etc. continuously occur on the earth.
(5) By the bio-geo-chemical cycles, the environmental balance is always maintained.
(6) If the environment is in proper condition, then human existence is possible. Therefore, it is our responsibility to preserve nature and maintain environmental balance.
(7) The planet Earth was given to us on lease from our future generations and not as an ancestral property from our ancestors. Therefore, we must conserve it for ourselves and for future generations.
Environmental Conservation : Due to natural and man-made causes, there are many environmental problems on the earth. These problems affect the existence of various living organisms. In order to save these organisms and maintain the environmental balance, there is need for environmental conservation.
Sensible or proper use of natural resources is also a way of environmental conservation