Grade 7 Life Science students learn how energy flows through ecosystems by exploring the roles of producers, consumers, and decomposers, as well as the processes of photosynthesis and chemosynthesis. The lesson covers feeding relationships through food chains, food webs, and energy pyramids to show how energy moves and changes between organisms. Part of Chapter 14 on Ecosystems and Biomes, this lesson builds on students' prior knowledge of matter cycles in nature.
Section 1
Producers Capture Sunlight to Create Food
Plants and algae use photosynthesis to transform sunlight into chemical energy stored in sugars. These organisms produce food that powers the entire ecosystem, making energy available to all other living things.
Section 2
Consumers Transfer Energy Through Eating
Animals obtain energy by consuming other organisms. Primary consumers eat producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers, creating a chain of energy transfer.
Section 3
Decomposers Recycle Dead Materials
Fungi and bacteria break down dead plants and animals into simpler compounds. These organisms extract the final bits of energy from once-living matter while returning nutrients to the soil for reuse.
Section 4
Food Webs Connect Multiple Feeding Pathways
Unlike simple food chains, food webs show complex interconnected feeding relationships between many producers and consumers. They demonstrate how organisms can play multiple roles and how removing one species affects many others.
Section 5
Energy Pyramids Show Decreasing Available Energy
As energy moves from producers to higher-level consumers, much is lost as heat at each transfer. Energy pyramids illustrate how available energy decreases at each feeding level, explaining why ecosystems have fewer top predators.
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Section 1
Producers Capture Sunlight to Create Food
Plants and algae use photosynthesis to transform sunlight into chemical energy stored in sugars. These organisms produce food that powers the entire ecosystem, making energy available to all other living things.
Section 2
Consumers Transfer Energy Through Eating
Animals obtain energy by consuming other organisms. Primary consumers eat producers, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers, creating a chain of energy transfer.
Section 3
Decomposers Recycle Dead Materials
Fungi and bacteria break down dead plants and animals into simpler compounds. These organisms extract the final bits of energy from once-living matter while returning nutrients to the soil for reuse.
Section 4
Food Webs Connect Multiple Feeding Pathways
Unlike simple food chains, food webs show complex interconnected feeding relationships between many producers and consumers. They demonstrate how organisms can play multiple roles and how removing one species affects many others.
Section 5
Energy Pyramids Show Decreasing Available Energy
As energy moves from producers to higher-level consumers, much is lost as heat at each transfer. Energy pyramids illustrate how available energy decreases at each feeding level, explaining why ecosystems have fewer top predators.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter