This packet is everything a parent or guide needs to assess Unit 04 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by dissecting an invertebrate and keying it to its phylum from the traits.
By the end of the Marine Invertebrates unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Dissect a specimen; key it to phylum from its traits.
The student defends the phylum call from the traits (Page 4).
Observations, traits, and the final phylum 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 handle the dissection and justify the phylum from the traits. 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 |
|---|---|---|
| Phyla & body plans | ||
| Invertebrate | animal without a backbone | Most sea animals; no vertebral column |
| Phylum | major animal group | The big branch (Porifera, Cnidaria, Mollusca, Arthropoda, Echinodermata) |
| Symmetry | body-plan symmetry | Radial (around a center) vs bilateral (mirror halves) |
| Traits, coral & ID | ||
| Cnidarian | jelly / coral / anemone | Stinging cnidocytes; radial; coral is a cnidarian polyp |
| Echinoderm | sea star / urchin group | Radial adults; moves on a water-vascular system |
| Arthropod | crab / shrimp group | Jointed exoskeleton; bilateral |
| Filter feeding | suspension feeding | Straining food from the water (e.g. sponges) |
| Zooxanthellae | symbiotic algae | Live in coral tissue; feed the polyp through photosynthesis |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Major phyla & defining traits | Groups all “sea bugs” together without distinction. | Names some phyla but mixes up their defining traits. | Identifies Porifera, Cnidaria, Mollusca, Arthropoda, and Echinodermata and gives a defining trait for each. |
| Body plans & symmetry | Cannot describe an animal’s symmetry. | Uses “radial” and “bilateral” but applies them to the wrong animals. | Distinguishes radial from bilateral symmetry and links each body plan to how the animal lives and moves. |
| Adaptations & feeding | Describes marine invertebrates as simple or all alike. | Names an adaptation but cannot tie it to survival. | Explains filter feeding, stinging cnidocytes, exoskeletons, and the water-vascular system as adaptations that solve real problems. |
| Coral as an animal | Calls coral a rock or a plant. | Knows coral is alive but not what kind of organism it is. | Explains that a coral is an animal — a cnidarian polyp — living with symbiotic zooxanthellae that feed it through photosynthesis. |
| Lab technique (invertebrate dissection & ID) | Damages the specimen or cannot use the key. | Dissects carefully but keys the animal to the wrong group. | Dissects an invertebrate cleanly and identifies it to phylum with a dichotomous key. |
| 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 trait behind the call: not just naming a phylum, but pointing to the feature that puts the animal there. Ask “what told you it was an arthropod?”
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 | Major phyla & defining traits | NY / Appr / Mast | |
| 2 | Body plans & symmetry | NY / Appr / Mast | |
| 3 | Adaptations & feeding | NY / Appr / Mast | |
| 4 | Coral as an animal | NY / Appr / Mast | |
| 5 | Lab technique (invertebrate dissection & ID) | 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.