Food Chain Trophic Levels YouTube Lecture Handouts

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Food Chain, Food Web and Ecological Pyramids - 3 Key Concepts in 1 Lecture

Food Chain Food Web Pyramids Bio-Magnification

This lecture explains what are food chains, food webs and ecological pyramids. She further explains the 3 types of ecological pyramids like pyramid of number, pyramid of biomass and pyramid of energy. She explains the possible cases including the upright and inverted pyramids.

Illustration: Food Chain Food Web Pyramids Bio-Magnification
Illustration: Food Chain Food Web Pyramids Bio-Magnification
Illustration: Food Chain Food Web Pyramids Bio-Magnification

Pyramid of Number

  • Number of organisms at different trophic levels of food chain.
  • Successive links of trophic structure decrease rapidly in number.
  • Ignores biomass of organisms and energy transferred.

Pyramid of Biomass

  • Indicates decrease of biomass in each tropical level from base to apex.
  • Biomass of the producers is more than biomass of the herbivores

Pyramid of Energy

  • Energy pyramid indicates role of organisms in the transfer of energy.
  • Illustrates energy needed as it flows upwards.
  • Total energy small organisms assimilate and pass on, may be considerably greater than that of organisms with a much larger biomass.
  • Energy pyramids slope because less energy is transferred from each level than was paid into it
Illustration: Pyramid of Energy
Illustration: Pyramid of Energy
  • Bio-concentration
  • Bioaccumulation
  • Bio-magnification

Manishika