Skill: write-like-james @ d1a2a04 · the build: write-lesson, write-mcqs, write-video-script @ d1a2a04

Topic 34 "Backbone or no backbone" — your read (29 September 2026)

The Life strand's third topic. Three lessons, one atom each: what a feature is and how one feature makes a group; the backbone that splits every animal into two groups; the three features that make an arthropod. Each lesson opens on a child's real question about a surprising case — two children sort the same six animal cards into different piles and both are right; a snake that bends into curves "has no bones"; a crab, a spider and a beetle that look nothing alike are put in one group — and runs the surprising members first: the snake and the fish have a backbone before the cat does; the worm has none before the crab; the crab is an arthropod before the beetle. Read by the author as you, then a non-author review (22 findings — 3 blocks, 7 fixes, 12 suggestions — every one applied or answered), then a cold read of every changed item (21 of 21 keys agreed over two cuts; the reader's nine flags are all applied or answered). Reply by number.

The three that unblock the bank

1. Do the nine question types stand, with the typed hard tier?

Your night ruling is applied: hard is typed — a scientist's new animal with "a line of bones down the middle of its back, inside" (type "vertebrate"), and a limpet with no backbone and a hard shell that is not an arthropod (type the feature it must be missing: "jointed legs"). Easy and medium are four-option MCQs and are the bulk. Every atom is tested alone and in a pair; every exemplar is a move and scene the topic uses nowhere else (a wolf and a beaver; a bat among a snail, a beetle and a jellyfish; a wasp; a trout in 'has scales'; a lizard and a goat in one group; an armadillo; a dog, a frog and a shark). One question inside this one: PP-6's distractors are the topic's own non-deciders (too big / four legs / lives on land); the cold reader would pick only "four legs" as tempting. Your call whether the bank's type 6 keeps that set or takes true-but-irrelevant facts about the animal instead. The same reader notes that L03's last quiz item and one practice item both list an arthropod's features and ask which one is missing or different — two moves on one option set; say if you want the practice one cut. The nine types, coverage, the design-move inventory

Approve all / strike these / edit these / change type 6's distractor set

2. Does "What an animal is" become an atom, LIF3-P01, before this topic?

Three of the findings for this age sit on the word, not on the sort: "animal" means a mammal; worms and insects are not animals; people are not animals. Topics 32 and 33 use "animal" plainly; this topic sorts "animals" and puts the student's own backbone in the vertebrate group ("You have a backbone too. So you are a vertebrate.") without ever saying that people are animals. No LIF3 atom defines the word, so no lesson can smash the finding without over-reaching its atom.

Recommendation: yes — a Fact atom before LIF3-010, one short lesson (a worm, a beetle, a fish, a person; a plant as the one non-example). The reviewer agrees. Until it exists, this topic stands with the one added clause. The proposal

Yes, LIF3-P01 / keep it to the one clause / add "People are animals too" to L02 now

3. On the three card items, do the students see name cards or photographs?

L01's attached question, one quiz item and one practice item show four white name cards (cow, hen, goat, duck) and ask which feature two of them share. The reviewer's point: a name card shows nothing to look at — the student answers from what they know of a hen, which is the skill, but the picture adds nothing the stem lacks; the summary uses photographs for the same move. Photographs cost three more photo slots for David and show the covering the coin is about.

Keep the name cards / photographs for all three / photographs for the attached question only

The lessons

4. L01 Make a group from one shared feature — Jethro and Kerensa each have the same six animal cards; Jethro makes three piles, Kerensa two, and their piles don't match. Something that is part of an animal's own body, like fur, feathers, legs or bones, is called a feature (the reviewer widened the coin so that "a backbone" counts — it was "something you can see"). Jethro picks fur and asks every card the same question; the lion and the bear go in, the other four stay out; feathers and scales make two more groups. Kerensa picks wings: the same cards, a different feature, so different groups — both were right. "Animals Kerensa likes" and "lives in the hot house" are not features. The rule: pick one feature; every animal with it goes in, every other animal stays out. Quiz: which feature a duck and a swan share, a fox and a squirrel, a crocodile and a gecko; is 'has fur', 'lives at the farm', 'animals Laszlo likes', 'has six legs' a feature; which of four drawn cards go in 'has feathers'; Lysette sorts her toy animals by wings and then by fur — same groups? (no); "feature" typed last. Article · script · quiz Fine / say where

5. L02 Backbone or no backbone — Mirren at the nature center: a snake winds round a branch in its tank, bending into curve after curve. "It has no bones. It's soft all the way through, like a worm." The X-ray picture shows a line of many small bones down its whole length: a backbone, and an animal with one is a vertebrate. Feel down your own back — you are a vertebrate too. The worm: long and thin, but nothing inside — an invertebrate ("in" means no). The fish's X-ray; the cat; the turtle, hard shell outside and a backbone inside, joined to the shell; the crab, hard shell outside and nothing inside. A hard shell on the outside is not a backbone. A tiny mouse has one; a giant squid as long as a bus has none. Quiz: an eel (drawn), a horse, a slug, an octopus (drawn), an owl, a mouse, a lobster; Ulysses's giant squid (no), Malachy's curling ferret (no), Vashti's frog (yes); which of three is a vertebrate; "vertebrate" and "invertebrate" typed last. Article · script · quiz Fine / say where

6. L03 What makes an animal an arthropod — Inigo's rock-pool crab, the spider in his room, the beetle on the step: what do they share? The crab's legs, close up: hard pieces that bend only at the joints — a jointed leg (your leg bends at the knee and the ankle too). Its shell is a hard outer casing; inside, no bones — no backbone. Three questions asked of the crab: yes, yes, yes — an arthropod. The spider and the beetle: three yeses. The turtle: hard shell, jointed legs, but a backbone — one no. The snail: no backbone, a hard shell, but no legs at all — one no. Quiz: a scorpion (drawn), a fly, a lizard, an earthworm, a lobster, a clam (drawn); Anouska's "every animal with a hard shell is an arthropod" (no), Dimitri's shrimp (yes); which feature every arthropod has (six legs is the trap); which of the three features the snail is missing; "arthropod" typed last. Article · script · quiz Fine / say where

Applied without asking

Hard bank items typed; every attached question stands alone with its own drawing (four farm-animal cards, a jellyfish, an ant; the summary's flamingo and crow, zebra, grasshopper); no option bundles a verdict with a reason and every claim is bare yes / no; every stem a positive question; the intro (Tallis in the aquarium tunnel: a shark, a jellyfish, a crab, an octopus — three go in one group and the shark is on its own; which three?) coins nothing, names no lesson, ends on a ready line and a poll, and the summary closes its question; scene changes spoken with "let's"; three questions on the summary; colour, and no drawn people (four cartoons and 30 photos briefed for David; the real animals are photographs, the two X-rays the strongest case); every verdict mark sits under its drawn question ("Has fur?", "A backbone inside?", "No backbone? / A hard outer casing? / Jointed legs?" — kept as "No backbone?" with a tick so every arthropod row is three yeses, the same shape as Topic 32's four-yes sort); surprising members first; the turtle kept as L02's boundary case and L03's first non-example (the armadillo stays in the bank); "living thing" and "animal" are Topics 32–33's words and none of their scenes or names reappear; Topic 35 is on disk and shares none of this topic's twenty names — its keeper-with-a-snake headache took this topic's original L02 scene, so Mirren's snake moved to a nature-center tank; nothing is said about insects (no atom asks); the mixed practice was re-instanced after the review so no item is a quiz item with a noun changed (its four term items repeat the quiz term items by design — recall is the practice's job); the register notes for LIF3-010, 011 and 070 wait in ATOM_PROPOSALS_G3T34.md for your word.

Also on the site

Topic intro and poll · summary and three questions · mixed practice · the blueprint's decisions · the type sheet

After you answer

1 → a bank of about fifty from the approved types, a second cold read, the hand-over folder for David. 2 → the register gains LIF3-P01 before Topic 34 (or the clause stands alone). 3 → three photo briefs replace three card drawings, or nothing changes. Register notes → the knowledge-graph repo.