Our Environment Blog 2

Our Environment

Important Instructions:

• Keep your text book open for reference.
• Home Assignment need to be done in your Biology note book.
• All the intext exercises as well as exercise given at the end of the chapter have to be done.

Learning outcomes:

• develop the definition of tropic level
• construct a food chain with different tropic levels
• calculate the amount of energy transferred among various tropic levels in a food chain

There are two period today, I will publish one more blog based on 'Sources of Energy'.

Trophic levels

Every step of food chain is called a tropic level.
The different tropic levels are –

• Producers (Tropic Level 1)
• Herbivores , Primary consumers (Tropic Level 2)
• Small carnivores or Secondary consumers (Tropic Level 3)
• Large Carnivores or Tertiary consumers(Tropic Level 4)

Pyramid of tropic levels (Page 258 Fig 15.2)

• Is a graphical representation.
• All the pyramids start with producers.

Law of conservation of energy

• Energy can neither be created nor destroyed; rather, it transforms from one form to another.
• In biological systems, it gets passed from one organism to another across tropic levels.

Energy flow (page 259 Fig 15.4)

• Transfer of energy from one trophic level to another depicting its direction and amount.
• Can be represented by the pyramid of energy.
• In any food chain, only 10% of the energy is transferred from one trophic level to another.

          (important page 258 second point with a bullet)

Food chain

A series of organisms each dependent on the next as a source of food.

Green plants convert 1% of solar energy into food energy. The flow of energy is unidirectional.

HOME ASSIGNMENT

• Why only an average of 10% of energy is transferred from one tropic level to the other
• Why is the flow of energy unidirectional.

    LEARN - PAGE 258 - (SENTENCES HIGHLIGHTED WITH A BULLET POINT)