conservation of plant and animal of Class 8

  • Term biodiversity means the variety of life forms and habitats found in a particular area. It refers to the whole variety of life on earth
  • Our earth supports millions of species of plants and animals which have been the result of billion years of evolution involving mutation, recombination and natural selection.


The Convention on Biological Diversity (CBD), which was developed and signed by 157 governments at the 1992 Earth Summit and today has 193 Parties, defines biodiversity in the following manner:

"Biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.”


It has three levels:

  • Ecosystem: It includes the diversity of ecological complexes or biotic communities found in a given area.
  • Species diversity: It refers to the variety of species in a region.
  • Species richness: It is the no. of species per unit area.
  • Genetic diversity: This includes the diversity of genes

Variations in the sequence of four base pairs which as a component of nucleic acids constitute the genetic code is the cause behind this diversity.


  • Change in latitude or altitude leads to change in biodiversity.
  • Biodiversity increases from poles to equator.
  • Number of species increase in area with favourable environmental conditions e.g. tropical rain forests.
  • On mountains decrease in species diversity takes place from lower to higher altitude.
  • High seasonal variations lead to reduction in biodiversity


It has following significances:

  • Ecosystem services: is an ecosystem destruction of one kind of wild life may upset the whole ecological balance because all the living organisms are closely interlinked.
  • Biodiversity is required for maintaining and sustainable use of goods and services from ecosystems.
  • Scientific importance: Wildlife acts as a source of gene bank for breeding programmes in agriculture, fisheries, animal husbandry etc. e.g. Fruit flies, Rabbits, Guinea pigs etc are used as research materials.
  • The wildlife acts as a source of new varieties.

DRUGS AND MEDICINE: Many diseases can be extracted from plants as morphine from Papaver somniferum used as analgesic, Quinine from Chinchona used for treatment of malaria.

COMMERCIAL IMPORTANCE: Wildlife is a renewable source and commercially very important as fresh water and marine fishes provide large amount of food.

  • Fur, skin, musk etc. can be obtained from wild animals.
  • Wild plants provide useful products like timber, gums, resins etc.

AESTHETIC IMPORTANCE: Many plants and animals are considered sacred and worshipped. e.g. Peepal, Tulsi, etc.

SPORT AND ENJOYMENT: Wildlife is important in games as hunting.


  • Plants act as producers in ecosystem.
  • They produce oxygen.
  • They act as habitat for animals.
  • Animals produce CO2 to balance cycle of O2 & CO2.
  • They produce a number of products like food, fur, musk, ivory.
  • Some animals help in pollination.
  • Some animals are used for transport and agriculture.
  • Microbes help in decomposition of organic matter and some of them fix atmospheric nitrogen.

RELIGIOUS IMPORTANCE: Different animals are considered as gods e.g. Matasya, Narsimha etc.

THREATS TO BIODIVERSITY: Extinction is the complete elimination of a wild species, it is a natural process and necessary to maintain ecological balance but due to destructive activities of man, rate of decline of wild life has become rapid.

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