Food Chains, Food Webs & Energy Flow — Practice · Grade 6 Science
Chapter: Ecosystems, Watersheds & ConservationWhat this practice covers
By the end of Food Chains, Food Webs & Energy Flow you should be able to:
- I can explain why energy flows through an ecosystem while matter cycles within it.
- I can use the ten per cent figure to calculate energy at each feeding level.
- I can explain why food chains rarely have more than four or five levels.
8 questions, written answer and multiple choice, each with a worked explanation.
Vocabulary used: producer, food web, evidence, system boundary, uncertainty.
Problem 1
Answer and explanation
The rabbit receives matter and chemical energy by eating the grass under the stated convention.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 2
Answer and explanation
It adds an alternative resource pathway, so removing one prey does not automatically describe all food available to the fox.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 3
Answer and explanation
No. They follow other pathways, including uneaten material, waste, activity, and thermal transfers; the model must account for them.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 4
Answer and explanation
No. Quantitative prediction requires population, feeding, movement, and time information beyond the drawn links.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 5
Answer and explanation
The arrows show receiving organisms obtaining matter and energy from resources. 80 ÷ 800 = 10% in the stated biomass-transfer model, not a universal percentage. The second fish provides another feeding route, and the web lacks population sizes and rates; it cannot specify an exact future bird count.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 6
Answer and explanation
Draw fish → bird, showing the direction of matter and energy transferred through feeding. State the convention so the arrow can be interpreted.
Compare the scientific meaning and reasoning after an independent attempt. A different accurate supported response can be correct; human review is required.
Problem 7
- One illustrative result establishes every real condition and needs no further evidence.
- Food-web arrows always point from predator toward prey.
- Every feeding transfer has exactly the same universal percentage.
- producer: An organism that builds organic matter using an energy source rather than feeding on organic food.
Answer and explanation
producer: An organism that builds organic matter using an energy source rather than feeding on organic food.
An organism that builds organic matter using an energy source rather than feeding on organic food. The arrows show receiving organisms obtaining matter and energy from resources. 80 ÷ 800 = 10% in the stated biomass-transfer model, not a universal percentage. The second fish provides another feeding route, and the web lacks population sizes and rates; it cannot specify an exact future bird count.
Problem 8
- food web: A model of connected feeding relationships among organisms.
- Food-web arrows always point from predator toward prey.
- Every feeding transfer has exactly the same universal percentage.
- One illustrative result establishes every real condition and needs no further evidence.
Answer and explanation
food web: A model of connected feeding relationships among organisms.
A model of connected feeding relationships among organisms. The arrows show receiving organisms obtaining matter and energy from resources. 80 ÷ 800 = 10% in the stated biomass-transfer model, not a universal percentage. The second fish provides another feeding route, and the web lacks population sizes and rates; it cannot specify an exact future bird count.