Feeding Relationships
Overview
Every organism needs energy, and that energy flows through an ecosystem from the Sun to producers and onward through consumers. Tracing who eats whom reveals the structure of an entire community and explains why large predators are always rare.
In this lesson you will learn the names of the trophic levels, how food chains and food webs represent feeding relationships, what pyramids of number, biomass and energy tell us, and why roughly 90% of energy is lost at every step along a food chain.
Objectives
- Understand the names given to different trophic levels, including producers, primary, secondary and tertiary consumers and decomposers
- Understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass and pyramids of energy transfer
- Understand the transfer of substances and energy along a food chain
- Understand why only about 10 per cent of energy is transferred from one trophic level to the next
Mind map
This topic is mapped out so you can see how the ideas connect.
Open the mind map in the app
Flashcards
Quick recall practice on the facts this topic is tested on.
Practise these cards in the app
Lesson Note
Complete Note Available on the Green Bridge App
Get the Green Bridge CBT app on your phone or computer for the complete IGCSE library: past papers, mark schemes, mind maps, flashcards and audio lessons.
Lesson Evaluation
Congratulations on completing the lesson on Feeding Relationships. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- What is the source of energy for almost all food chains? A) Chemical energy in the soil B) Heat from the Earth's core C) Light energy from the Sun D) Kinetic energy from wind Answer: C
- Which trophic level do decomposers belong to? A) First B) Second C) They act at all levels D) Fourth Answer: C
- A pyramid of biomass is always pyramid-shaped because: A) There are always more producers than consumers B) Total dry mass decreases at each trophic level C) Producers are always larger than consumers D) Consumers always eat everything available Answer: B
- Approximately what percentage of energy is transferred from one trophic level to the next? A) 1% B) 10% C) 50% D) 90% Answer: B
- In a food chain, arrows represent: A) The direction an organism moves B) The direction of energy transfer C) The size of the organism D) The number of organisms Answer: B
Work through these questions in the app
Work through these questions in the app
Practice Mock Questions
Want to practice mock questions on Feeding Relationships? Download the Green Bridge CBT app to access mock questions and full practice assessments for this topic.
Download The App On Google Playstore
Everything you need to excel in your exams
