Biology Lesson 2 Cycles in Nature
Learning Objectives: In this chapter you will learn:
• The meaning of the terms: species, population, community, habitat, ecosystem and biosphere
• The concepts of food chain, food web, the pyramid of number, pyramid of biomass and pyramid of energy ­ the transfer of energy between different trophic levels and its relative efficiency; the importance of producers, consumers and decomposers in the cycling of nutrients
• The water, nitrogen and carbon cycles
• The roles of decomposers and scavengers Suggested Time Allocation: Part Theme 1 The meaning of the terms: species, population, community, habitat, ecosystem and biosphere The concepts of food chain, food web, the pyramid of number, pyramid of biomass and pyramid of energy ­ the transfer of energy between different trophic levels and its relative efficiency; the importance of producers, consumers and decomposers in the cycling of nutrients The water, nitrogen and carbon cycles The roles of decomposers and scavengers Total time suggested: 2 3 4 Suggested Time Allocation 30 mins 150 mins 60 mins 30 mins 270 mins (4.5 hours)
After studying this topic students should be able to: • define species, population, community, habitat, ecosystem and biosphere and describe their interrelationship; • draw food chain, food web, the pyramid of number, pyramid of biomass and pyramid of energy; • explain the flow of energy within an ecosystem; • assess the efficiency of energy transfer between trophic levels; • relate the concept of energy flow between different trophic levels to photosynthesis, respiration and chemosynthesis; • explain the roles of producers, consumers and decomposers in the cycling of nutrients; • state the major stages of the water, nitrogen and carbon cycles. • evaluate the importance of the nitrogen and carbon cycles. • develop an awareness of the effects of human interference on the nitrogen and carbon cycles. • distinguish decomposers and scavengers.