This chapter explains how organisms hold their shape and move. The four lessons go from the skeleton and muscles, to muscle pairs, to other organisms, to reading diagrams.
It is part of SPM Biology, and it builds on tissue ideas in the cells and organisation chapter.
How do the four lessons connect?
Each lesson adds one layer.
- Relating bones, joints and muscles names the parts and what joins them.
- Explaining antagonistic muscle action shows why muscles work in pairs.
- Comparing support in selected organisms contrasts skeletons and support systems.
- Interpreting movement diagrams teaches you to read the diagrams in questions.
What does lifting a bag show?
You lift a school bag from a desk by bending your elbow. The biceps contracts and pulls on the radius through a tendon, the elbow joint acts as the pivot, and the forearm bone moves as a lever. At the same moment the triceps relaxes, so it does not resist.
When you lower the bag, the triceps contracts and the biceps relaxes. One action uses bone, joint, muscle, tendon and the pair of muscles that work in opposition.
Who should start where?
If the labels bones, tendons and ligaments blur, begin with lesson one. If the bag example makes sense but you cannot write it, go to lesson two. If you need to compare a human with a grasshopper, an earthworm or a plant, start at lesson three.
If diagrams are your weak point, lesson four is the quickest fix. Test yourself with the support and movement practice set.
When does extra help make sense?
Movement answers are short, so one wrong word, such as relaxing for contracting, can cost the whole mark. A teacher who reads your answer line by line can point out the word that reverses the meaning.
If that sounds useful, see online one-to-one Biology tuition and mention support and movement when you enquire.