Difference between Vertebrates and Invertebrates

Animals are classified into two main groups: vertebrates and invertebrates. Let us see how vertebrates differ from invertebrates!

Vertebrates:

Vertebrates are the animals that have a spinal cord encased in a hard protective backbone (spine or vertebral column). The backbone, which is a column made of vertebrae, protects the spinal cord and supports the body. The word vertebrate is derived from vertebrae, the bones that make up the spine. Some common examples of vertebrates (animals with backbone) include birds, reptiles, fish, mammals and amphibians.

Vertebrates are the members of the subphylum Vertebrata which comes under the phylum Chordata. Vertebrata is the largest subphylum of chordates. They are the most advanced organisms on Earth. The characteristic features that make them special include spinal cord, vertebrae and notochords. The notochord is a hollow nerve cord that appears in the embryos of the vertebrates in the mid-dorsal line of the body. In adults, it is replaced by the spine or backbone.

Invertebrates:

Invertebrates are the animals that do not have a spine or backbone. They are the most abundant animals on the earth and found in diverse habitats such as upper reaches of the atmosphere, driest deserts, frozen Antarctic, deepest ocean floor and canopies of the wettest rainforests. So, they can live anywhere and come in various shapes and sizes. Some common examples of vertebrates include sponges, jellyfish, starfish, arthropods etc. They also lack notochord and are cold-blooded animals as their blood temperature changes with the outside temperature; it remains equal to the temperature of the outside environment. More than 90% of all living species on the Earth are invertebrates.

Based on the above information, some of the key differences between vertebrates and invertebrates are as follows:

Vertebrates	Invertebrates
They have spine or backbone.	These animals lack the spine or backbone.
Notochord, a self-supporting rod, is present in the embryos during the embryonic period.	They lack notochord.
Generally, large and fast-moving animals.	Generally, small and slow-moving animals.
They comprise only 2-3% of the total animal species found on Earth.	They comprise more than 90% of the total animal species found on Earth.
Pharynx has pharyngeal clefts to aid breathing.	They do not have pharyngeal clefts.
Their central nervous system is located in the mid-dorsal line.	Their central nervous system is located in the mid-ventral line.
They have a living endoskeleton made of bones and cartilage.	Some of the invertebrates have a hard non-living exoskeleton or shell.
Their heart is located on the ventral side of the body.	Their heart is located on the ventral side of the body.
The circulatory system is closed.	The circulatory system is open.
They are warm-blooded animals. Their body temperature remains constant. It does not vary with the temperature of the outside environment.	They are cold-blood animals. Their body temperature varies with the outside temperature and remains equal to the outside temperature.
Red blood cells, which contain hemoglobin, are present.	Red blood cells are absent.
Mostly include unisexual animals.	Mostly include hermaphroditic animals.
They do not have compound eyes.	They have compound eyes.
Common examples: birds, fish, amphibians, reptiles, mammals etc.	Common examples: sponges, jellyfish, worms, starfish, cockroaches etc.