Q.How does the reptilian mode of reproduction differ from that of amphibians, and why is this significant for a fully terrestrial life?

Step 1. Amphibians typically show external fertilisation, and the fertilised egg lacks a protective shell, so it must be laid in water; development is indirect, passing through an aquatic larval (tadpole) stage before metamorphosis.

Step 2. Reptiles, by contrast, show internal fertilisation, and the fertilised egg is enclosed in a protective calcareous shell — the amniotic egg — that can be laid directly on land. …

Contrast fertilisation type, egg structure and presence/absence of a larval stage between the two classes, then link …

• Saying reptiles 'do not need water at all' without qualifying that this specifically concerns reproduction, since many reptiles still live in or near water for other reasons. …