Unit 2. The classification of living things

Question	Answer
Vertebrates	Vertebrates are multicellular animals that have a spinal column. They are classified into five groups: mammals, reptiles, fish, birds and amphibians.
Invertebrates	Invertebrates area multicellular animals too but they don´t have a spinal column.
Characteristics of mammals	Respiration: All mammals have lungs to breathe air Mammals´bodies: Skin and hair cover mammals´bodies. In some animals, the hair is thick an called fur Extremities: Most terrestrial mammals have four legs, but humans beings have two legs and two arms. Aquatic mammals sucha as whales and dolphins, have fins for swimming. Many terrestrial mammals also have a tail Reproduction: Almost all mammals are viviparous. This means that female mammals give birth to live young. They produce milk to feed their young.
Characteristics of reptiles	Respiration: Reptiles have lungs to breathe air Reptile bodies: Reptiles have hard scales to protect their body. Some reptiles, such as tortoises and turtles, have a hard shell. Extremities: Many reptiles have four legs, but snakes are reptiles that don´t have legs Reproduction: Reptiles are oviparous animals. This means that their young are born from eggs. Reptiles lay their eggs on land.

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	Created by Isabel Hernán over 9 years ago