Vertebrates
Biology: Cambridge International GCSE Supplement, topic 1.3.3
Vertebrates
Animals can be divided into vertebrates and invertebrates. Vertebrates have a backbone, and can be further divided into five classes.
Mammals
- Mammals have mammary (milk) glands, sweat glands and give birth to live young.
- They also have four limbs and hair or fur.
- Humans, dolphins and bears are mammals.
Birds
- Birds have feathers, two wings and two legs (which have scales).
- They lay hard-shelled eggs on land and they have lightweight bones.
- Penguins, sparrows and eagles are birds.
Reptiles
- Reptiles lay waterproof eggs on land and, excluding snakes, have four limbs.
- They have dry, scaly skin.
- Crocodiles, turtles and chameleons are reptiles.
Amphibians
- Amphibians lay eggs covered in jelly, in water.
- They have moist scale-less skin, often have webbed feet, and perform gas exchange through their lungs and skin.
- Newts and frogs are amphibians.
Fish
- Fish have scales, fins and a lateral line (a line that runs down the middle of their bodies).
- They have gills for gas exchange in water.
- Sharks, salmon and clownfish are all fish.
Test yourself on Vertebrates
Which of these applies to both reptiles and birds?
Which class of vertebrates perform gas exchange through their skin?