Zoology · Ch 2 — Kingdom Animalia
Class Reptilia
Class Reptilia
Reptilia (Latin repere/reptum, to creep or crawl) are mostly terrestrial animals, and their body is covered by dry, cornified skin bearing epidermal scales or scutes — the key adaptation that let them break away from the amphibians' dependence on moist skin and water. Reptiles typically have a three-chambered heart, though crocodiles uniquely have a four-chambered heart among reptiles. All reptiles are cold-blooded (poikilothermic) amniotes.
Most reptiles lay cleidoic (shelled) eggs equipped with extraembryonic membranes — the amnion, allantois, chorion and yolk sac — which together let the embryo develop on dry land without drying out or needing a water body for reproduction, unlike amphibians. Excretion is carried out by metanephric kidneys, and reptiles are uricotelic (excreting nitrogenous waste as relatively insoluble uric acid, which conserves water — another land adaptation). Reptiles are monoecious, fertilisation is internal, and all are oviparous. …
What this figure shows. Four reptile body forms: King cobra, a long limbless scaled body capable of raising and flattening its neck into a hood; Draco (flying lizard), a lizard body with a fold of skin stretched between elongated ribs on each side, used to glide between trees; Crocodile, a heavily armoured, elongated body with short powerful limbs, a long muscular tail and a long tooth-lined snout; and Chameleon, a lizard body with independently rotating eyes, a prehensile tail and specialised zygodac …
| Feature | Tortoise | Turtle |
|---|---|---|
| Habitat | Spend most of their life on land | Spend most of their life in the water |
| Carapace shape | Usually dome-shaped | Laterally compressed and streamlined |
| Habit | Are primarily terrestrial | Mostly live in the water or are always found near it |