Three Skeleton Solutions

Overview

In this first lesson of Skeletons: Structure in Action, students build on their knowledge of animal body parts by investigating three ways animals are supported: endoskeletons, exoskeletons and hydroskeletons. Through rapid sorting, hands-on stations and discussion, they classify Aotearoa animals and connect skeleton structure with support, protection and movement.

Learning intentions

• WALT define endoskeleton, exoskeleton and hydroskeleton.
• WALT identify and compare skeleton types in different animals.
• WALT explain how skeleton structures support protection and movement.
• WALT use scientific vocabulary to justify a classification.

Success criteria

• I can define all three skeleton types.
• I can correctly classify examples, including Aotearoa animals.
• I can compare how different skeletons provide support, protection and movement.
• I can justify my decisions using evidence and scientific vocabulary.

Curriculum links

• Living World: investigating how animals’ structures support movement and provide protection.
• Investigating in Science: observing, sorting, comparing and communicating evidence-based explanations.
• Thinking: making connections between structure and function and defending a classification.
• Using language, symbols, and texts: interpreting images and models and using scientific vocabulary to communicate ideas.

Lesson structure (50 minutes)

1. 0–5 min · Brain gym sorting challenge. Display three headings—“inside”, “outside” and “fluid-supported”—using the opening sorting challenge and give pairs six quick animal prompts or images to place under a heading. Students make an initial classification, then share one decision and a question they have; accept provisional ideas without correcting every response.

2. 5–13 min · Explicit teaching and modelling. Use the skeleton types teaching slides to introduce:

• Endoskeleton: an internal framework of bones or cartilage, as in people, tuatara, kākāpō and longfin eel.
• Exoskeleton: a hard supporting covering on the outside, as in giant wētā and kōura.
• Hydroskeleton: support produced by fluid pressure inside a flexible body, as in earthworms and jellyfish. Model a think-aloud: “A kōura has an exoskeleton because its hard covering is outside its body. It provides support and protection, but the animal must moult to grow.” Students repeat key terms, sketch the three types and suggest how each could help an animal move.

3. 13–16 min · Station instructions. Show the station rotation instructions and explain that pairs will examine a model or image, identify the skeleton type, and record evidence on the skeleton investigation worksheet. Demonstrate the sentence frame: “I classify ___ as a ___ because ___. This structure helps it to ___.” Establish movement between stations, careful handling and a two-minute warning.

4. 16–34 min · Hands-on investigation rotations. Set up three stations, with pairs spending approximately six minutes at each:

• Station A—inside: models or images of tuatara, kākāpō and longfin eel.
• Station B—outside: models or images of giant wētā and kōura.
• Station C—fluid-supported: models or images of earthworms and jellyfish. Students observe, discuss and complete the classification and structure–function table on the worksheet. At each station they must record one piece of evidence and one movement or protection benefit. Circulate and ask, “What do you observe?”, “Where is the support located?” and “How does that structure help the animal?” Refer back to the station prompt and vocabulary slides when pairs need support.

5. 34–43 min · Compare and justify. Display the comparison discussion slides. Pairs choose two animals with different skeleton types and complete a short comparison using “both”, “whereas” and “because”. Invite several pairs to defend a classification, including a longfin eel: although its body is flexible, it has an internal skeleton. Address the misconception that only animals with obvious bones have skeletons. Students revise any uncertain worksheet answers after hearing the evidence.

6. 43–50 min · Recap test and peer marking. Students complete the five-question recap on the recap test and reflection section independently: define the three types, classify one named animal, and explain one support, protection or movement function. Display the recap and peer-marking slides with answers and success criteria. Students swap with a partner, mark carefully, discuss one answer they improved, and hand in the worksheet or record an exit response: “One skeleton type I understand is ___ because ___.”

Resources

• the Three Skeleton Solutions slide deck
• the skeleton investigation worksheet
• Three station signs: endoskeleton, exoskeleton, hydroskeleton
• Animal models, plastic specimens or printed images
• Animal name and image cards: tuatara, kākāpō, giant wētā, kōura, earthworm, jellyfish and longfin eel
• Whiteboard and markers
• Timer
• Pencils and coloured pencils

Assessment

• Listen during the opening sort and stations for correct use of “internal”, “external”, “fluid”, “support”, “protection” and “movement”.
• Check station tables for accurate classifications and evidence-based sentence frames; question students who sort from appearance alone.
• Use the recap test and exit response to identify students who need further teaching of a skeleton definition or structure–function link in Lesson 2.

Differentiation

• Use mixed-ability pairs, labelled picture cards, a word bank and sentence starters on the worksheet. Allow students to explain orally while a partner or teacher records key ideas.
• Provide enlarged, dyslexia-friendly text in a clear sans-serif font, reduced reading load, strong contrast and uncluttered station cards. Offer text-to-speech or teacher-read passages.
• Give students who need further support a pre-selected animal and two possible skeleton types before asking them to justify the choice. Use gestures and simple diagrams for “inside”, “outside” and “fluid-supported”.
• For extension, students research an unusual animal skeleton, such as a shell-bearing mollusc or another fluid-supported animal, and explain its advantages and limitations. They may also defend a contested classification using evidence and structure–function vocabulary.