What is the difference between vertebrates and invertebrates?

To many people, the only difference between vertebrates and invertebrates is that the former is the biological term used for animals with a backbone (vertebral column), while the latter is the biological term for animals without a backbone. While this is true, there are other differences between vertebrates and invertebrates. In terms of classification, vertebrates are classified into five groups, namely; reptiles, mammals, amphibians, birds, and fish, while invertebrate have 30 different phyla.

There are about 57,000 named species of vertebrates, while invertebrates are more than two million, and there are still a whole lot of them that are yet to be identified and named. Vertebrates generally have big sizes depending on their nature, and this can be attributed to the well-structured internal skeletons they possess. Invertebrates, on the other hand, don't move very fast and they are small. Examples of vertebrates are; humans, dogs, snake, eagles, etc. Examples of invertebrates are; snails, earthworms, amoebas, sea urchins, etc.

One of the more apparent differences between vertebrates and invertebrates is their size. Invertebrates such as worms, insects, and shellfish are delicate. They do not possess efficient support or the muscles to move beyond a very slow-moving pace. They do not have a backbone, or a skeleton, while vertebrates have a backbone, spinal cord, and a skeleton.

The diversity of the invertebrate species is exceptionally high compared to vertebrates. Vertebrates are bilaterally symmetrical, while invertebrates can either be bilateral or radial symmetry. Vertebrates have a well -developed brain, a more intricate nervous system, a closed blood system, and either gills or lungs for respiration. Invertebrates lack all of these variables.

Vertebrates are animals develop and possess vertebral column which serves main functions. The vertebral column is derived from the notochord. Vertebrates have a closed circulatory system where blood is transported across the body in blood vessels. They also have a more complex respiratory system. Unlike invertebrates, all vertebrates belong to a single phylum. Examples of vertebrates are mammals, birds, fish, reptiles, and amphibians.

Invertebrates, on the other hand, animals that do not have or develop vertebral column; to compensate for this, invertebrates have an exoskeleton. The exoskeleton is simply an external skeleton that protects their soft body. Most invertebrates have an open circulatory system where blood flows in an open cavity. They also possess a simple respiratory system, which consists mostly of trachea or gills.

Invertebrates are also the most abundant animals on earth. Over 90% of all living animal species are invertebrates. Invertebrate animals are distributed between more than 35 phyla. Examples of invertebrates are arthropods, annelids, cnidarians, and mollusks.