Difference Between Vertebrates and Invertebrates

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Vertebrates and Invertebrates in the animal kingdom are the animals that have been classified into two main categories based on the presence or absence of the backbone or a spinal column. Apart from this, there are more differences between vertebrates and invertebrates. Read on to explore how these classes of organisms differ from each other.

What are Vertebrates?

Vertebrates are organisms that have an internal backbone surrounded by bone, also called vertebrae. They have a hard skeleton made of bone, that supports the body’s tissue and anchor muscle. Animals that don’t have spines are called invertebrates.

Vertebrates can be separated into five broad groups. This includes the following:

  • Mammals – Mammals have warm blood and usually have hair or fur on their bodies. Mammals are born alive and the mothers feed their babies with milk. Humans are mammals, but other examples of mammals include lions, cats, and sheep.
  • Bird – Birds are warm-blooded and have beaks, feathers, wings, and two legs. They lay their eggs on land.
  • Fish – Fish live and lay their eggs in water. They have fins instead of legs and gills instead of lungs.
  • Reptile – Reptiles live in water and on land. They have scales and are cold-blooded. This means that they cannot keep warm by themselves and need to be in a warm place. They lay their eggs on land. Examples of reptiles include lizards, snakes, and turtles.
  • Amphibian – Amphibians live on land and in water, however, they lay their eggs in water. They are cold-blooded and have smooth skin. Examples of amphibians include frogs, toads, and salamanders.

What Are Invertebrates?

Invertebrate, any animal that lacks a vertebral column, or backbone, in contrast to the cartilaginous or bony vertebrates. More than 90 percent of all living animal species are invertebrates. Worldwide in distribution, they include animals as diverse as sea stars, sea urchins, earthworms, sponges, jellyfish, lobsters, crabs, insects, spiders, snails, clams, and squid. Invertebrates are especially important as agricultural pests, parasites, or agents for the transmission of parasitic infections to humans and other vertebrates.

Invertebrates serve as food for humans; are key elements in food chains that support birds, fish, and many other vertebrate species; and play important roles in plant pollination. Despite providing important environmental services, invertebrates are often ancillary in wildlife research and conservation, with priority given instead to studies that focus on large vertebrates. In addition, several invertebrate groups (including many types of insects and worms) are viewed solely as pests, and by the early 21st century the heavy use of pesticides worldwide had caused substantial population declines among bees, wasps, and other terrestrial insects.

Apart from the absence of a vertebral column, invertebrates have little in common. Indeed, they are distributed into more than 30 phyla. In contrast, all vertebrates are contained within a single phylum, the Chordata. (Phylum Chordata also includes the sea squirts and some other invertebrate groups.) Invertebrates are generally soft-bodied animals that lack a rigid internal skeleton for the attachment of muscles but often possess a hard outer skeleton (as in most mollusks, crustaceans, and insects) that serves, as well, for body protection.

Major Differences between Vertebrates and Invertebrates :

Skeleton is present Skeleton is absent
Backbone is present Backbone is absent
The heart is present on the ventral side of the body The heart is present on the dorsal side of the body
The nerve cord is dorsal and hollow The nerve cord is ventral and solid
They have two pairs of limbs They have three or more pairs of limbs if present
Hemoglobin is present in RBC Hemoglobin if present dissolved.


Vertebrates are the most advanced of species in the animal kingdom. Members possess a well-defined internal skeleton system, which includes a backbone. Invertebrates can be simply identified as animals that do not have a backbone. They are found almost everywhere, from the hottest deserts and the deepest seabeds to the darkest caves and the tallest mountains. Apart from this, there are more differences between vertebrates and invertebrates

Also, read Differences between Frog and Toad.

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