Environment: Air, Water, and Land Systems:

Earth’s environment encompasses the interconnected systems of air, water, and land, supporting life and ecosystems. It sustains biodiversity, regulates climate, and provides resources vital for human survival and well-being. Air, water, and land are essential elements of Earth’s environment. Air sustains life with oxygen, water supports ecosystems and human needs, and land provides habitats and resources for diverse species.

What constitutes the composition of Earth’s atmosphere and how does it impact our Environment?

• Earth’s Atmosphere Layers: Our earth is surrounded by a thin layer of air. 
  • This layer extends up to many kilometres above the surface of the earth and is called the atmosphere. 
  • As we move higher in the atmosphere, the air gets rarer.
• Gaseous Mix in Our Atmosphere: Air is a mixture of many gases. 
  • Few of its components are listed as under:  
• Water Vapour
  • Oxygen: Oxygen in the Atmosphere is replaced through photosynthesis. 
    • Maintaining Balance: The balance of oxygen and carbon dioxide in the atmosphere is maintained through respiration in plants and animals and by the photosynthesis in plants.
  • Nitrogen : The major part of air (which does not support burning candles) is nitrogen.
  • Carbon Dioxide: Carbon dioxide makes up a small component of the air around us. 
    • Plants and animals consume oxygen for respiration and produce carbon dioxide. 
    • Plant and animal matter also consumes oxygen on burning and produces mainly carbon dioxide and a few other gases.
  • Dust and Smoke:  The burning of fuel also produces smoke. 
    • Smoke contains a few gases and fine dust particles and is often harmful. 
    • Dust particles are always present in the air. 
    • The presence of dust particles in air varies from time to time, and from place to place.

How does Oxygen interact with water and soil?

• When someone heats up water, the air dissolved in it escapes first. 
  • Then, the water itself turns into vapour and begins to boil. 
  • The bubbles you see in boiling water are made of water vapour.
• A lot of burrows and holes are formed in deep soil by the animals living in the soil. 
  • These burrows also make spaces available for air to move in and out of the soil.

Environment: Definitions, Ecosystem Dynamics and Historical Significance: l

• Definition: The sum total of all biotic (related to living beings) and abiotic (related to non-living) factors, substances and conditions that surround and potentially influence organisms without becoming their constituent part.
• Ecosystem: It is a structural and functional unit of the biosphere consisting of living beings and their physical environment and the interaction among them. 
  • Term ‘Ecosystem’ was coined by A.G. Tansley in 1935.

How does the intricate web of food chains influence the dynamics of the environment?

• Intricate threads of ecosystem Food Chains: A food chain refers to the order of events in an ecosystem, where one living organism eats another organism, and later that organism is consumed by another larger organism. 
• Web of Life in Ecosystem Food Chains: Organisms depend on the producers for their nourishment. 
  • The organisms, whether consuming food directly from producers or indirectly by preying on other consumers, are referred to as consumers. 
  • Various organisms at different biotic levels come together to form a food chain.
• Trophic Levels and Consumer Relationships: Each level within the food chain is termed a trophic level. 
  • Autotrophs: The initial trophic level consists of autotrophs or producers, responsible for harnessing solar energy and making it accessible for heterotrophs, or consumers. 
  • Primary and Secondary Consumers: Herbivores, or primary consumers, occupy the second trophic level, while smaller carnivores, or secondary consumers, are found at the third level. 
  • Tertiary Consumers: Larger carnivores, or tertiary consumers, constitute the fourth trophic level.
• The Flow of Nutrients and Energy from one organism to another at different trophic levels forms a food chain.

 Grass→ insects→ frog→ snake →eagle

• Interconnected Chain and Ecosystem stability: Forests contain numerous interconnected food chains, and these chains are interdependent. 
  • Every aspect of the forest relies on other components. 
  • Disrupting one food chain has repercussions on others within the ecosystem.
• Unidirectional Energy Flow and Trophic Level Losses: Interactions among environmental components involve the transfer of energy from one part of the system to another. 
  • This energy flow is unidirectional.
  • In terrestrial ecosystems, green plants capture approximately 1% of the sunlight’s energy falling on their leaves and convert it into food energy.
  • As energy progresses through trophic levels, it steadily diminishes due to losses at each level. 
  • Much energy is dissipated as heat to the environment, some is expended on digestion and work, and the remainder goes towards growth and reproduction.
• 10% Rule  and Trophic Level Dynamics: Typically, only 10% of the food an organism consumes is transformed into its own body mass and becomes available for the subsequent level of consumers in the food chain. 
  • Because so little energy is available for the next level of consumers, food chains usually consist of just three or four steps. 
  • The substantial energy loss at each step means that very little usable energy remains after four trophic levels.
• At the lower trophic levels of an ecosystem, there are generally more individuals, with the largest population being the producers.
• Food Webs in Ecosystem: Food webs exhibit significant variations in terms of length and complexity. 
  • Instead of a linear food chain, each organism is typically consumed by multiple other species, which, in turn, are prey for several other organisms. 
  • This complex relationship is often depicted as a network of branching lines rather than a straight line food chain.

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