Food chains and energy flow
Build a food chain from organisms found around a Nepali paddy field, place each at its feeding level, and follow how energy is lost at every step.
Core concept
Energy flows from producers through consumers in a food chain; only about a tenth of the energy passes to each next level
Topic: Ecosystems
A food chain: Who eats whom: grass is eaten by a goat, and the goat by a tiger. All key words shows who eats whom, and so how energy: What is needed to make things move, heat up, light up or grow. All key words passes from one living thing to the next. It always starts with a producer, a green plant that makes food from sunlight. Next comes a primary consumer (a herbivore) that eats the plant, then a secondary consumer that eats the herbivore, and so on up to a top predator. At each step most of the energy is used for living or lost as heat; only about a tenth passes on. In a real habitat: The natural home of a plant or animal, like a pond or a forest. All key words, food chains link together into a food web, because most animals eat, and are eaten by, more than one kind of organism.
What you will learn
- Build a food chain in the correct order.
- Name producers and primary, secondary, tertiary and top consumers.
- Explain why energy decreases along a food chain.
Before you start
- Know that green plants make their own food by photosynthesis.
Materials
- Picture cards of paddy grass, grasshopper, frog, snake and eagle
Equipment
- None for the virtual lab
Procedure
- Choose an organism card and find out what it eats and how much energy reaches it.
- Place each organism at its level in the food chain, from producer to top consumer.