CAIE IGCSE Biology 1.2.4 Constructing & Using Dichotomous Keys
Practise following paired choices and constructing statements that identify organisms from visible, contrasting features.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise following paired choices and constructing statements that identify organisms from visible, contrasting features.
Fig. 1.1 shows four arthropods.

Fig. 1.1
Fig. 1.2 is a dichotomous key for the arthropods shown in Fig. 1.1.
Complete Fig. 1.2 by writing suitable statements in:
- box 2 to identify species B
- box 3 to separate species C and A.

Fig. 1.2
Box 2: any one from: animal has, 3 pairs of legs / 6 legs / less 4 pairs of legs / less than 8 legs ; wings ; head, thorax, abdomen / body in three sections ; no, pincers / claws / carapace ;
Box 3: any one from: (animal has) claws / pincers, of different sizes / AW ; eyes on stalks ; smooth, carapace / body / 'shell' ; body, has five sides / is angular ; hairs / bristles / AW, on, legs / claws ;