Classes of Animals
Mammals
- warm-blooded
- born alive and with fur or hair
- breathe air through lungs
- vertebrate (has backbone) and four limbs
- examples: bears, dolphins, tigers, and people
Birds
- warm-blooded
- has feathers, two legs, and two wings
- vertebrate (has backbone)
- lay eggs and their young hatch from the eggs
- examples: tiny hummingbird and large ostrich
Fishes
- cold-blooded
- vertebrate (has backbone)
- lives in water with scales and fins and breathes through gills
- lay eggs and their young hatch from the eggs
- examples: salmon, puffer fish, and gold fish
Reptiles
- cold-blooded
- has short legs or no legs with dry scaly skin
- vertebrate (has backbone)
- born on land and breathe through their lungs
- examples: snakes, turtles, and liquids
Amphibians
- cold-blooded
- lays their eggs in the water
- spends part of their lives under water and land
- breathes with gills or lungs or through their skin
- vertebrate (has backbone) and skin is moist and doesn't have scales
- examples: frogs, newts, and salamanders.
Invertebrates
- cold-blooded
- doesn't have backbone has external skeleton
- segmented body and has many jointed limbs
- 85% of animals are invertebrates
- most common examples: protozoa, mollusks, and arthropods