Invertebrates And Vertebrates- What’s the Difference?

vertebrates and invertebrates are two main animal groups. Vertebrates have a backbone, like humans, dogs, birds, and fish. Invertebrates don’t have a backbone, such as insects, spiders, and jellyfish. Vertebrates have an inner skeleton of bone or cartilage, while invertebrates often have no skeleton or an outer shell.

Most animals are invertebrates. They make up about 97% of all animal species. Vertebrates are usually bigger and more complex. But invertebrates come in many shapes and sizes, from tiny bugs to large octopuses.

Invertebrates vs Vertebrates

Here are the main differences between Invertebrates and Vertebrates:

Aspect	Invertebrates	Vertebrates
Definition	Animals without a backbone	Animals with a backbone
Diversity	Vast majority of animal species are invertebrates	Smaller number of species compared to invertebrates
Body Structure	Varied body structures and forms	More complex body structures and internal skeletons
Skeletal System	Lack a bony skeleton; may have exoskeletons, shells, or no hard structure	Possess an internal skeleton made of bones or cartilage
Nervous System	Diverse nervous system types, including nerve nets and ganglia	Possess a well-developed centralized nervous system, including a brain and spinal cord
Reproduction	Various modes of reproduction, including sexual and asexual	Mostly sexual reproduction, with internal fertilization being common
Size Range	Varies greatly in size, from microscopic to large sizes	Sizes range from small to very large
Habitat	Occupy diverse habitats, including terrestrial, aquatic, and aerial environments	Found in a wide range of habitats, including terrestrial, aquatic, and aerial environments
Exoskeleton	Have an exoskeleton	Do not possess an exoskeleton
Circulatory System	Majority have an open circulatory system	Possess a closed circulatory system
Eyes	Many have compound eyes	Do not have compound eyes
Body Symmetry	Includes radial or bilateral body symmetry	All have bilateral body symmetry
Mode of Nutrition	Autotrophic, parasitic, and heterotrophic	Usually heterotrophic
Species Distribution	95% of animal species are invertebrates	5% of animal species are vertebrates
Examples	Flatworms, arthropods, sponges, insects, worms, mollusks, jellyfish, sponges	Mammals, fish, reptiles, amphibians, birds