Vertebrates have a backbone and a complex skeleton, while invertebrates don’t. Vertebrates are usually bigger and more advanced, while invertebrates include smaller and simpler animals.

Key Points

• Vertebrates: Backbone present, advanced organ systems (e.g., mammals, birds, fish).
• Invertebrates: No backbone, simpler body structure (e.g., insects, worms, jellyfish).
• Percentage: 95% of animals are invertebrates.