our environment

• plankton: a diverse group of typically microscopic, aquatic organisms suspended in the water column and rely on water currents to move.
• 1. An environment is the surroundings where organisms live.
  2. It comprises physical components.
  3. It provides a living space for the elements.
  4. It provides the conditions to live.
  5. It can be micro or macro.
  6. An organism's environment changes as it moves from one place to another.
• 1. An ecosystem is a community where the biotic and abiotic components interact with each other.
  2. It comprises biological components.
  3. It provides interaction between the elements.
  4. It provides the relation between the components of life.
  5. It can be aquatic or terrestrial.
  6. The ecosystem remains the same no matter where the organism travels.
• The 10% law states that only 10% of the energy entering a particular trophic level of organisms is available for the transfer to the next higher trophic level.
• All green plants and certain blue-green algae which can produce food by photosynthesis are called the producers.
• Those organisms that consume the food produced, either directly from producers or indirectly by feeding on other consumers are called consumers.
• Those microorganisms that break down complex organic substances into simple inorganic substances that go into the soil and are used up once more by the plants are called decomposers.
• The autotrophs capture the energy present in the sunlight and convert it into chemical energy.
• The green plants in a terrestrial ecosystem capture about 1% of the energy of sunlight that falls on their leaves and convert it into food energy.
• A food chain is a linear sequence of organisms where food and energy are transferred from one organism to another.
• When many individual food chains occur in an ecosystem, it is called a food web.
• The 1% law states that green plants absorb only 1% of the sunlight and convert it into food energy. With this, only 1% of energy will be passed onto the next trophic level.
• The various steps in a food chain at which the transfer of food (or energy) takes place are called trophic levels.
• The increase in the concentration of harmful chemical substances like pesticides in the body of living organisms at each trophic level of a food chain is called biological magnification.
• DDT (dichloro diphenyl trichloroethane) is an insecticide used for agriculture. It cannot be broken down into simpler, harmless substances and harm the environment.
• Methods of Garbage Disposal:

  1. Recycling: process of waste materials to form new substances
  2. Composting: bio-degradable wastes are buried in a pit dug into the ground, they are converted into composts and are used as manures.
  3. Landfills: solid waste is dumped into a low-lying are and covered with soil.
  4. Sewage treatment: sewage is carried into sewage treatment plants.
• Garbage management is the disposal of waste generated by us in such a manner that it does not affect our environment adversely.
• Ozone shields the surface of the earth from ultraviolet (UV) radiation from the Sun.