Year 7 Science | Victorian Curriculum 2.0
Classifying living things
Topic 01 | Biological sciences | Answer key

Year 7 answers

Fluency

Tier 1: recall and identify

    1. Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.
    2. Kingdom, Phylum, Class, Order, Family, Genus, Species.
    3. Animalia, Plantae, Fungi, Protista, Monera (Bacteria).
    4. Homo sapiens (genus capitalised, species lowercase, both italicised).
    5. Two organisms in the same family — family is a narrower group than class, so members are more closely related.
    6. A tool for identifying organisms by answering a series of either-or questions about observable features.
    7. (a) A mushroom, yeast or bread mould. (b) An amoeba, paramecium or algae.
    8. Colour varies with age, sex, season, and lighting, and is often subjective — so different users classify the same organism differently.
    9. Genus: Felis. Species name: catus.
    10. No. A flame releases energy and moves but does not grow (in the biological sense), reproduce, excrete waste, or sense its environment. It fails most of MRS GREN.
Reasoning

Tier 2: explain and reason

    1. Kingdom Protista — single-celled eukaryotes (nucleus present) that cannot photosynthesise fit the protist description best.
    2. No. The standard biological species definition requires that members can interbreed and produce fertile offspring. Looking identical is not enough.
    3. Whales have fur (at least as embryos), produce milk, breathe air through lungs, and give birth to live young — all mammal features. Fish have gills, scales and lay eggs.
    4. (i) Genus must be capitalised: Homo. (ii) Both words must be italicised (or underlined when handwritten).
    5. Viruses reproduce but only inside a host, and they cannot respire, grow, take in nutrition or excrete on their own. They fail most MRS GREN tests, so most biologists classify them as non-living.
    6. Either-or keeps each step unambiguous — there is exactly one correct branch. Three-way splits often overlap and confuse the user.
Reasoning

Tier 3: apply to a novel context

    1. Example key. Step 1: lives entirely in water? Yes → goldfish. No → step 2. Step 2: has feathers? Yes → sparrow. No → step 3. Step 3: has fur? Yes → wombat. No → frog.
    2. Kingdom Animalia — only animals have feathers (specifically birds).
    3. Officers check: number of legs, wings, antennae, body segmentation, mouthparts, size. Correct identification decides whether the insect is a biosecurity threat (e.g. a fruit fly vs a harmless native), whether the cargo is destroyed or released, and the cost to agriculture.
    4. Accept any correct table where each organism has a unique combination of the three feature values. Example features: “has feathers”, “lives in water”, “larger than 50 cm”.
Reasoning

Challenge

    1. Science changes its mind when better evidence arrives — this self-correcting property is what makes it reliable over time. Classifications based on DNA reflect true evolutionary relationships more accurately than guesses from appearance.
    2. Before the platypus, “mammal = gives birth to live young” was assumed. The platypus showed that milk production is the better defining feature. It is still a mammal because it has fur, a four-chambered heart, and produces milk; monotremes are a group of egg-laying mammals.
    3. Example key. Step 1: lives entirely in water? Yes → crocodile or clownfish. No → step 2. Step 2 (for aquatic): scales and fins? Yes → clownfish. No → saltwater crocodile. Step 2 (for land): feathers? Yes → emu. No → step 3. Step 3: has a pouch and hops? Yes → red kangaroo. No → step 4. Step 4: has spines? Yes → echidna. No → koala.
    4. No nucleus → Monera (Bacteria). Photosynthesises → specifically a cyanobacterium. Critical features: absence of a nucleus and presence of chlorophyll.
Year 7 Science study companion | Answer key