CAIE IGCSE Biology 18.2.1 Defining an Adaptive Feature
Practise defining an adaptive feature as inherited and explaining how it helps survival and reproduction in an environment.
- Syllabus
- 2026–2028
- Course
- Biology 0610
Practise defining an adaptive feature as inherited and explaining how it helps survival and reproduction in an environment.
The Hawaiian happy-face spider, Theridion grallator, is found on several of the Hawaiian islands. Some of the spiders have a very distinctive pattern on their bodies as shown in Fig. 1.3.

Fig. 1.3
Scientists think that the pattern on the bodies of the spiders is an adaptive feature. Explain the term adaptive feature with reference to this pattern.
inherited feature / controlled by gene(s) / allele(s) / DNA ; functional / AW, feature ;
increase, fitness / chances of survival ; increases chance of reproducing (to leave offspring) ; any suitable example visible in T. grallator ; e.g. camouflage / warning signal / scares predators / lure for prey / sexual attractant