Animal Classification
Scientists classify animals into groups based on shared characteristics. The two main groups are vertebrates (animals with a backbone) and invertebrates (without a backbone).
What You Need to Know
Key Concept Diagram
Vertebrates have a backbone and include fish, amphibians, reptiles, birds, and mammals
Invertebrates do not have a backbone and make up about 97% of all animal species
Mammals are warm-blooded, breathe air, give birth to live young, and nurse them with milk
Classification helps scientists communicate about and study organisms
Key Vocabulary
Vertebrate
An animal with a backbone (e.g. fish, birds, mammals, reptiles, amphibians)
Invertebrate
An animal without a backbone (e.g. insects, spiders, worms, jellyfish)
Mammal
A warm-blooded vertebrate that feeds its young with milk
Classification
Grouping organisms based on shared characteristics
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Which animal is a vertebrate?
Question 2
Approximately what percentage of all animal species are invertebrates?
Question 3
Which feature is unique to mammals?
Key Concepts Summary
- ●Vertebrates have a backbone and include fish, amphibians, reptiles, birds, and mammals
- ●Invertebrates do not have a backbone and make up about 97% of all animal species
- ●Mammals are warm-blooded, breathe air, give birth to live young, and nurse them with milk
- ●Classification helps scientists communicate about and study organisms