This packet is everything a parent or guide needs to assess Unit 04 at home — the technique targets, the calibration anchors, the mastery rubric, and a clipboard score sheet. No written test: the student shows mastery by opening a real mollusk and locating, naming, and explaining its structures while you watch.
By the end of the Clam or Squid unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Open the specimen and locate, name, and explain real structures — watched live.
The student explains why each structure does its job (Page 4 anchors).
Careful observations of the external and internal structures kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both perform the technique cleanly and locate, name, and explain the structures on the actual specimen. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad afternoon never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Shell & body wall | ||
| Shell / valves | the two halves (clam) | The hard outer covering; a clam’s two halves are its valves |
| Mantle | body wall | The tissue layer that secretes the shell and lines the cavity |
| Foot | muscular foot | The muscular organ for digging or anchoring; not a leg |
| Adductor muscles | shell-closing muscles | Hold the valves shut; cut them to open a clam |
| Water & movement | ||
| Siphons | incurrent / excurrent tubes | Draw water in and push it out; not the gut |
| Gills (ctenidia) | ctenidia | Feathery structures for gas exchange and filter feeding |
| Funnel | siphon (squid) | The squid’s jet nozzle; drives jet propulsion |
| Arms & tentacles | appendages (squid) | Squid has eight arms and two longer tentacles |
| Gut & squid-only parts | ||
| Gut | digestive tract | The digestive tube; distinct from the feathery gills |
| Pen | gladius | The squid’s stiff internal support; the reduced “shell” |
| Ink sac | ink gland | Stores ink the squid releases to escape; squid only |
| Beak | jaws (squid) | The hard mouthpart at the center of the arms; squid only |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Instrument handling & safe technique | Forces the shell open or slashes through the mantle, destroying the soft parts inside. | Opens the shell or mantle with reminders but still cuts too deep and nicks the organs. | Holds each instrument the right way and opens the shell or mantle with shallow, controlled cuts that spare the soft parts, safely for both the student and the specimen. |
| Careful exposure & observation of the mantle cavity | Tears into the mantle cavity and disturbs the organs before looking at them. | Opens the mantle cavity roughly but disturbs the gills or gut before observing their layout. | Opens the mantle cavity cleanly along the correct line and observes the arrangement of structures before disturbing anything. |
| Locating & naming external structures | Cannot point to the shell or mantle, the foot, or the siphons. | Finds a few external parts with prompting but confuses the foot, siphons, or (for a squid) the arms and tentacles. | Locates and names the external structures on the specimen — shell or valves, mantle, foot, and siphons; or for a squid the mantle, arms, tentacles, funnel, and eyes. |
| Locating & naming internal structures | Guesses at the organs or names the wrong ones once the specimen is open. | Finds the larger organs but cannot reliably distinguish the gills from the gut or trace the adductor muscles. | Locates and names the internal structures on the specimen — gills (ctenidia), gut, and adductor muscles; or for a squid the pen, ink sac, and beak. |
| Explaining structure & function (and specimen care) | Cannot say what a structure does, and lets the specimen dry out or handles it carelessly. | Explains one or two structures' functions but not the rest, and keeps the specimen moist only when reminded. | Explains why key structures do their jobs — the gills drawing oxygen from water as the clam filter feeds, the squid’s funnel driving jet propulsion — while keeping the specimen moist, handling it respectfully, and cleaning up afterward. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
The split between Approaching and Mastered is the real specimen over the label: naming an organ from memory is not the same as pointing to it on the tray. Ask the student to find the gills and say what they do; the answer should match the feathery structure in front of them.
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | Instrument handling & safe technique | NY / Appr / Mast | |
| 2 | Careful exposure & observation of the mantle cavity | NY / Appr / Mast | |
| 3 | Locating & naming external structures | NY / Appr / Mast | |
| 4 | Locating & naming internal structures | NY / Appr / Mast | |
| 5 | Explaining structure & function (and specimen care) | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.