Grade 7 Science Unit 2 | Teacher Guide and Answers

Grade 7 Science Unit 2 | Teacher Guide and Answers

Teach one lesson and eight questions each day. Use observation from a distance and never require a student to capture or handle wildlife. Adult supervision is appropriate outdoors. Assess Day 5 independently, one point per question; accept equivalent correct answers. A suggested 6/8 is a teaching guide, not a validated proficiency score.

Source record: Original explanations and questions developed for this unit. Factual references reviewed: Smithsonian National Museum of Natural History, What Is an Insect?; Smithsonian Insect Zoo Audio Description Tour; and Smithsonian Gardens, About Butterflies. Links direct readers to the publishers; no images or passages have been reproduced.

Day 1: Insects and body plans

1. Head, thorax and abdomen.
2. Six.
3. Thorax.
4. For example, sensing or feeding.
5. No.
6. Eight.
7. Arachnids.
8. Both share arthropod traits such as jointed appendages and an external skeleton.

Day 2: Structures and functions

1. A body part or physical feature.
2. What a structure does.
3. Sensing the environment, such as odors or touch.
4. Thorax.
5. Protection of the flight wings and body.
6. Shedding the old outer covering.
7. The butterfly extends its proboscis into the flower.
8. Possible inference: it may be taking in nectar.

Day 3: Life cycles and metamorphosis

1. Egg, larva, pupa, adult.
2. Larva.
3. Pupa.
4. Egg, nymph, adult.
5. Grasshopper.
6. Molting.
7. Yes, generally.
8. They are different structures from the three pairs of jointed thoracic legs.

Day 4: Classification and evidence

1. A series of choices based on traits used to identify or group organisms.
2. Spider.
3. Beetle.
4. Butterfly.
5. No, it is limited to the described choices and organisms.
6. A defining feature may be missing or obscured.
7. For example, leg count and wing features.
8. It could bite, sting or be harmed; observe with adult supervision.

Day 5: Independent science assessment

1. Head, thorax and abdomen.
2. Six.
3. No; a spider has eight legs and is an arachnid.
4. Egg, larva, pupa, adult.
5. Nymph.
6. Beetle, using the limited classroom key.
7. The claim that it is eating the leaf, unless eating is directly observed.
8. Answers vary; identify that the key covers only selected organisms and traits, and that others may not fit.

Reteaching and extension

Sketch a typical adult insect and label body regions and leg attachment. Sort illustrated life stages using the two models, noting that individual species vary. For extension, compare two reliable references and describe a feature that the simple classroom key does not cover.