Explore the intricate relationships within ecosystems and the impact of human activities on the environment. This document delves into biodegradable and non-biodegradable waste, highlighting their effects on nature. It covers the importance of decomposers, food chains, and the flow of energy in ecosystems. Learn about the consequences of removing organisms from trophic levels and the significance of recycling and waste disposal methods. Ideal for students and educators interested in environmental science and sustainability.

Key Points

  • Explains the differences between biodegradable and non-biodegradable waste.
  • Discusses the role of decomposers in nutrient recycling within ecosystems.
  • Illustrates food chains and food webs, emphasizing energy transfer between trophic levels.
  • Analyzes the effects of human activities on ecosystems, including waste disposal methods.
ARTI KANNAUJIYA
6 pages
Language:English
Type:Textbook
Ecology
ARTI KANNAUJIYA
6 pages
Language:English
Type:Textbook
Ecology
84
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OUR ENVIRONMENT
The environment includes physical surroundings like air, water, soil and organisms like plant ,
animals & microbes like bacteria & fungi.
Wastes are of two types-
a) Biodegradable waste- These waste material which can be broken down in to simpler
non poisonous substances in nature by microbes. For eg.-all waste produced by plant &
animal like paper, wool, grass, leather etc.
These waste generally do not pollute the environment but if their amount is large & it
cannot be degraded in nature at right time, can pollute the environment in the following
ways-
i) It act as breeding place for flies.
ii) It causes foul smell.
b) Non-biodegradable waste- These waste materials cannot be broken down in simple,
harmless substances in nature. For eg.-DDT, plastic, glass, pen refills, synthetic fibres,
metal articles, radio active waste etc.
Q Why some materials are biodegradable and some are nonbiodegradable?
Ans. The microbes are specific in action. They break down the natural material but cannot
break down man made materials.
ECOSYSTEM- A self sustained unit of living organisms and non living environment is called an
ecosystem.
It is of two types-
a) Natural : Desert, forest, mountain, sea, river, ocean etc.
b) Manmade: kitchen garden, park, crop field, aquarium etc.
On the basis of habitat, ecosystem is of two types-
a) Terrestrial : garden, park, desert, mountain etc.
b) Aquatic: pond, river, sea, aquarium etc.
Components of ecosystem-
a) Abiotic components- It includes soil, water, air along with inorganic substances like
CO
2,
nitrogen, oxygen, sodium, potassium etc. It also include physical factors like light,
temperature, pressure, humidity.
b) Biotic components- It includes producers,consumers and decomposers.
Importance of decomposers-
1 They help in decomposing the dead bodies of plants and animals so act as cleansing
agent of environment.
2 They help in returning the nutrients elements to the soil, air & water which were initially
taken by plants.
3 They help in recycling materials in the ecosystem so the process of life may go on and on.
Food chain- The sequence of living organisms in a community in which one organism
consumes another organism to transfer food energy is called food chain. For eg.-
Grass --------------→ Insect ------------------→ Frog -----------------------→ Bird
(producer) (herbivore) (carnivore) (Top carnivore)
Plant ---------------→ Worms ------------------→ Birds -------------------→ Cats
Algae or phytoplankton --------------→zooplankton---------→small fish-------→large fish
Note- Food chain starts with green plants & ultimate source of energy is sun.
Food web- The network of large number of food chains in an ecosystem is called food
web.
Example from the NCERT
Tropic level- The various steps in the food chain at which the transfer of energy or food
take place are called tropic level.
TOP
CARNIVORE IV
TROPIC LEVL
CARNIVORE
III TROPIC LEVEL
III
HERBIVORE
II TROPIC LEVEL
PRODUCER
I TROPIC LEVEL
Effects of men’s activities on the ecosystem-
Men’s activities like hunting leads to imbalance in the functioning of the ecosystem and
ultimately to the functioning of the biosphere.
For eg.- Formation of Sahara Desert- When Romans started capturing lions, their population
reduced greatly. Lion is a predator of herbivores, so their population increased rapidly. Due to
overgrazing the lush green forest converted into Sahara Desert.
Effect of removing all the organisms of one tropic level from the food chain-
Grass ----------------→ Deer -------------------------→ Lion
If all the lions are removed- As mentioned above
If all the deer are removed- Deer are prey of the lion. If all the deer are removed, lions will not
get sufficient food and they will die due to starvation. It will disturb the other food chains in
which lions are present. Hungry lions may come out of the forest and may kill other animals and
humans. In this way, removal of deer disturb the ecosystem.
If all producers are removed- If all green plants are removed then herbivore and carnivore will
not get food as they all depends directly or indirectly on plant for their food.
So we can conclude that if we remove all the organisms of one tropic level it will cause a lot of
damage to the ecosystem. All the organisms of one tropic level cannot be removed without
causing damage to the environment but removing of all the organisms from one tropic level is
different from other tropic level.
Transfer of energy in a food chain-
1) There is continuous transfer of energy from one tropic level to another.
2) At each tropic level, some of the energy is utilized for metabolic activities like
respiration and growth.
3) Some part of the energy is lost at every tropic level in the form of heat and remain
unutilized.
4) The flow of energy in the ecosystem is unidirectional, it means that energy which enters
in the producers from the sun is passed on from one organism to another but never
return back to the plants.
Flow of materials in the ecosystem is cyclic.
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FAQs

What are the two types of waste mentioned in the document?
The document identifies two types of waste: biodegradable and non-biodegradable waste. Biodegradable waste can be broken down into simpler, non-poisonous substances by microbes, such as paper, wool, and food scraps. In contrast, non-biodegradable waste cannot be decomposed naturally and includes materials like plastics, glass, and radioactive waste.
What is the significance of decomposers in an ecosystem?
Decomposers play a crucial role in ecosystems by breaking down dead bodies of plants and animals, acting as cleansing agents for the environment. They return essential nutrients to the soil, air, and water, facilitating nutrient cycling. This process ensures that the ecosystem remains sustainable and that life continues uninterrupted.
How does energy transfer occur in a food chain according to the document?
Energy transfer in a food chain occurs in a unidirectional flow, starting from producers to various consumer levels. Each trophic level utilizes some energy for metabolic activities, while a portion is lost as heat. The document highlights that only about ten percent of energy is transferred from one trophic level to the next, which limits the number of trophic levels in a food chain.
What is biomagnification and its cause?
Biomagnification refers to the increasing concentration of harmful chemicals, like pesticides, in the bodies of living organisms at each trophic level of a food chain. This phenomenon occurs because these substances are non-biodegradable, accumulating as they move up the food chain, ultimately affecting organisms at higher trophic levels.
What are the effects of removing organisms from a trophic level?
Removing organisms from a trophic level can severely disrupt the ecosystem. For instance, if all lions (top carnivores) are removed, the deer population may increase unchecked, leading to overgrazing. Conversely, if all deer (herbivores) are removed, lions would face starvation, potentially leading them to hunt other species or even humans, illustrating the interconnectedness of trophic levels.
What methods are suggested for the disposal of domestic waste?
The document outlines several methods for disposing of domestic waste, including recycling, composting, incineration, landfills, and sewage treatment. Recycling involves reprocessing materials like paper and plastic. Composting converts biodegradable waste into manure. Incineration burns chemical waste at high temperatures, while landfills involve burying solid waste in designated areas. Sewage treatment processes wastewater to prevent pollution.
What is the ten percent law in energy transfer?
The ten percent law, proposed by Lindemann in 1942, states that only ten percent of energy is transferred to the next higher trophic level in a food chain. This principle explains why food chains typically do not exceed three or four levels, as the energy available becomes insufficient to sustain life beyond this point.

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