Need for Conservation

• Pollution


  • The addition of harmful substances to the environment, making it undesirable for life.
  • Substances that cause pollution are called pollutants.
• Discharging untreated sewage into water sources


  • Pathogens from sewage (e.g. bacteria) may enter sources of drinking water like rivers or lakes, causing water-borne diseases like cholera and typhoid
• Eutrophication in water bodies


  • Phosphates and nitrates enter water due to dumping of untreated sewage or excess fertilisers washing into water bodies
  • Lead to eutrophication, the excessive growth of algae and floating water plants
  • Overgrowth of algae and floating water plants block sunlight from reaching the submerged plants
  • Submerged plants unable to photosynthesize & die
  • Dead plants decomposed by aerobic bacteria
  • Aerobic bacteria multiplies and use up dissolved oxygen
  • Causing other aquatic organisms to die due to lack of oxygen
• Pollution due to insecticides

  • Insects may become resistant to the insecticides
  • Offspring may inherit the beneficial insecticide resistance gene when adults reproduce.
• bioaccumulation


  • concentration of DDT in an individual organism’s body increasing as it continues to consume food containing DDT.
• biomagnification

  • concentration of DDT increases up the trophic levels as DDT gets passed on in the food chain
  • Top consumers at highest trophic level may suffer toxic effects from DDT due to highest concentration of DDT.
• DDT (dichlorodiphenyltrichloroethane)


  • DDT (dichlorodiphenyltrichloroethane): non-biodegradable insecticide that cannot be broken down in organisms. It is insoluble in water and not excreted out of the body via urine therefore, stored within the fatty tissues of organisms that consumed it
• Plastic wastes


  • Plastic is a synthetic polymer that is made of many repeating units
  • Largely non-biodegradable, resulting in bioaccumulation in organism and biomagnification up the food chain.
  • Trapped in digestive and respiratory system of marine animals, preventing digestion and gaseous exchange.
  • Potential health hazards (allergy, metabolic disruptions, immune response, etc.) when absorbed into bloodstream and tissue cells.