What is a Reptile?

Reptiles inhabit diverse environments and vary greatly in size. They are cold-blooded vertebrates, relying on external heat sources to regulate body temperature. Unlike mammals, reptiles can survive long periods without food. They breathe air and have a three-chambered heart, an evolutionary step between fish and mammals. Reptiles reproduce internally but lay eggs, which require stable temperatures for development. Their skin, made of beta keratin scales, allows them to thrive in dry conditions. Despite their diversity, reptiles share common features such as cold-bloodedness, egg-laying, and scaly skin.

What is a key characteristic of all reptiles that affects their energy consumption compared to mammals?

• They are warm-blooded.

• They are cold-blooded.

• They have a four-chambered heart.

• They give birth to live young.

How do semi-aquatic reptiles like the Galapagos iguanas manage to feed underwater?

• They do not need oxygen while underwater.

• They absorb oxygen through their skin.

• They can hold their breath while diving.

• They have gills for breathing underwater.

What is the evolutionary significance of the reptile heart?

• It has five chambers, unique to reptiles.

• It has two chambers like a fish.

• It has three chambers, a midpoint between fish and mammals.

• It has four chambers like a mammal.

What is the primary component of reptile scales that makes them waterproof?

• Alpha keratin

• Beta keratin

• Collagen

• Chitin

Why can reptiles survive in dry environments better than amphibians?

• They have permeable skin.

• They have scales that prevent moisture loss.

• They need to stay close to water.

• They have gills for breathing.