Chapter - 15
Life on Earth
️ Biosphere :-
The biosphere is made up of the mutual interrelationship of all the plants, animals, animals (including the micro-organisms living on the earth) and the environment around them. The biosphere and its components are very important elements of the environment.
️ Ecology :-
The word ecology is made up of two Greek words oikos and lozi. Oikos literally means home and loji means science and study. That is, the study of the earth as the home of plants, humans, animals and micro-organisms is called ecology.
️ Ecology :-
^ German zoologist Ernst Hückel (1869) is known as the scientist of ecology. The study of the relationship between biotic and non-living components is called ecology.
️ Ecological Adaptation :-
Different types of ecosystems are found in different types of environment and in different conditions, different types of plants and animals gradually get used to the same environment i.e. adapt themselves to the environment. This is called ecological adaptation.
️ Biomes :-
The community of plants and animals found in a geographical area is called a biome. Such as forests, deserts, grasslands, wetlands, mountains, plateaus, estuaries, coral reefs, swamps and swamps etc.
Ecosystem: -
Such an interrelationship of living organisms of a particular group with land, water and air in a particular area, in which energy flow and nutrition chains are clearly adjusted, it is called ecosystem.
️ Types of Ecosystem :-
Ecosystems are mainly of two types :-
- Terrestrial Ecosystem
- Aquatic ecosystem
️ Terrestrial ecosystem :-
The local ecosystem can be further divided into biomes. A biome is a community of plants and animals found over a large geographical area. Precipitation, temperature, humidity and soil determine the nature and extent of a biome. Some of the world's major ecosystems include forests, grasslands, deserts, coasts and tundra regions. Apart from these, tidal estuaries, coral reefs, ocean floor are also included in this.
️ Aquatic ecosystem :-
The aquatic ecosystem is divided into marine ecosystem and fresh water ecosystem. Marine ecosystem includes ocean, estuary, coral reef ecosystem. The fresh water ecosystem includes lakes, ponds, streams, marshes and marshes.
️ Abiotic factors :-
Abiotic factors include temperature, rainfall, sunlight, humidity, soil conditions and inorganic elements (carbon-di-oxide, water, nitrogen, calcium, phosphorus, potassium, etc.).
️ Biological factors :-
It includes all the biological elements of the environment. The biological components of the biosphere range from micro-organisms to birds, mammals, aquatic animals, and reptiles. Humans are also an example of this biological component. All these living beings are interdependent, that is why they are divided into the category of producers, consumers and decomposers.
️ Producer :-
Producers are organisms that make their own food through the process of photosynthesis, so they are also called autotrophic organisms. They are also called primary producers. Example – Plants, algae, grass etc.
️ Consumers :-
These organisms depend on producers
- primary consumer
- secondary consumer
- tertiary consumer
️ Primary Consumers :-
These organisms depend on plants for their food supply. Such as - grasshopper sheep, goat, rabbit, etc.
️ Secondary Consumer :-
They get their food by killing other living beings. They get their food from the primary consumer. These are carnivorous examples – wolf, fox, bird, snake /-
️ Tertiary Consumers :-
These organisms are dependent on primary and secondary consumers like – shark, hawk, lion etc.
️ Decomposers :-
Decomposers are those which depend on dead organisms such as crows and vultures and some other decomposers such as bacteria and micro-organisms which decompose the dead into simpler substances.
️ Functions of Ecosystem or Functions of Ecosystem :-
- energy flow
- food chain
- food web
- biogeochemistry cycle
️ Energy Flow :-
The flow of energy in an ecosystem can be understood by the food or energy pyramid.
The producer is placed at the lowest level in the pyramid.
Second and third consumers are placed after producers.
Producers make their own food by photosynthesis, but primary consumers are able to take in only 10% of the energy from producers.
Secondary consumers take 10% of the energy available with the primary consumers, according to this rule, only 10% of the energy from one trophic level to another trophic level is received.
️ Food chain :-
In any ecosystem, all the organisms depend on each other for food. In this way, all living beings depend on each other to form a food chain, due to which food energy flows in the ecosystem. The flow of food energy from one level to another is called the food chain. It consists of three to five levels. At each level the energy decreases.
️ Types of food chain :-
There are generally two types of food chains.
- grazing food chain
- detritus food chain
️ Grazing Food Chain :-
Begins from plants (producers) to carnivores (tertiary consumers), in which herbivores are at a moderate level. There is a loss of energy at every level which includes the processes of respiration, excretion and decomposition. Organic matter comes out in it.
️ Detritus food chain :-
Grazing is dependent on dead matter from the chain and involves the decomposition of organic matter.
️ Detritus Nutrients :-
Consumer group that depends on dead animals obtained from grazing food chain.
️ Biogeochemical cycle :-
Various studies have shown that in the last 100 million years, the balance of chemical components in the composition of the atmosphere and the water body has remained the same i.e. without change. This balance is maintained by the cyclic flow of chemicals through the tissues. This cycle begins with the absorption of chemical elements by organisms and resumes with their dissolution in air, water and soil. These cycles are mainly driven by solar heat. The cyclic flow of chemical elements in the biosphere between the organism and the environment is called the biogeochemical cycle.
️ Types of Biogeochemical Cycle :-
- gaseous cycle
- sedimentary cycle
️ Gaseous cycle :-
Here the store / source of matter is the atmosphere and the oceans.
️ Sedimentary cycle :-
Here the main store of matter is soil, sediments and other rocks found on the earth's crust.
️ Oxygen cycle :-
The chakra describes how oxygen circulates in various forms through nature. Oxygen occurs freely in the air, trapped in the Earth's cycle as chemical compounds, or dissolved in water.
Oxygen is about 21% in our atmosphere, and it is considered the second most abundant gas after nitrogen. It is mostly used by living organisms, especially humans and animals in respiration. Oxygen is also the most common and important element of the human body.
️ Carbon cycle :-
Carbon is found in all living organisms, it is the basic element of all organic compounds, in the biosphere innumerable carbon compounds are present in the form.
The carbon cycle is the process through which air, land, plants, animals, and fossil fuels move through this cycle.
People and animals take in oxygen from the air and remove carbon dioxide (CO2), while plants absorb CO2 for photosynthesis and emit oxygen back into the atmosphere.
️ Nitrogen cycle :-
The atmosphere is 79% nitrogen. Only some specific organisms, soil, bacteria and blue-green algae can ingest it directly.
The main source of free nitrogen is the action of soil micro-organisms and the soil containing the roots and stomata of related plants, from where it reaches the atmosphere.
Nitrogen is fixed by lightning and space radiation in the atmosphere and assimilation takes place in green plants.
The dead plant and animal wastes are converted into nitrites by bacteria present in the soil.
Some bacteria are able to convert these nitrates back into free nitrogen, this process is called de-nitrification.
️ Situational Balance :-
Ecological balance is the state of mutual dynamic equilibrium between a community of organisms in an ecosystem or habitat. It can exist as a stable equilibrium of the number of each species in an ecosystem only when there is a balance in the relative number of different organisms living in an ecosystem. It depends on the fact that some organisms depend on other organisms for their food, for example, herbivores like deer, zebra, buffalo etc. On the other hand, carnivorous animals like tigers and lions depend on herbivores for their food and their numbers are relatively small or their numbers are controlled.
Ecological imbalance: -
There is a balance between the living beings and the physical environment in the world, but when this balance is disturbed, an ecological imbalance arises.
Four factors of ecological imbalance: -
Population Growth :- Due to continuous population growth the pressure of population on natural resources increases and situation of ecological imbalance arises.
Destruction of forest wealth: - The destruction of forest wealth (both by man and nature) also creates a situation of ecological imbalance, due to excessive rainfall, soil erosion by floods or drought also destroys forests.
Technological progress: - Due to the continuous progress, the industrial sector is increasing and the smoke and waste materials coming out of them pollute the environment and spoil the ecological balance .
Lack of carnivorous animals: - Due to the lack of non-vegetarian animals, the number of herbivorous animals increases and vegetation (grasses and shrubs) are eaten in large quantities by them. Due to which the vegetation cover on the hills decreases and the intensity of soil erosion increases due to which a situation of ecological imbalance arises.
Why is the biosphere important?
Any kind of life is possible in the biosphere itself, it is also the basic source of food for human beings. Helps organisms to survive, grow and develop. So it is very important for us.
️ Damage due to environmental imbalance :-
Natural disasters such as floods, earthquakes, diseases and many climatic changes occur due to environmental imbalance.
