Characteristics of vertebrates
* Backbone: Vertebrates have a backbone, or spinal column, that runs along the length of their body. The backbone is made up of a series of bones called vertebrae.
* Notochord: Vertebrates also have a notochord, which is a flexible rod that runs along the back of the embryo. The notochord is the precursor to the backbone.
* Paired appendages: Vertebrates have paired appendages, such as legs, arms, wings, or fins.
* Closed circulatory system: Vertebrates have a closed circulatory system, meaning that their blood is contained within blood vessels.
* Pharyngeal slits: Vertebrates have pharyngeal slits, which are openings in the throat that lead to the gills or lungs.
* Post-anal tail: Vertebrates have a post-anal tail, which is a tail that extends beyond the anus.
Evolution of vertebrates
Vertebrates evolved from a group of animals called the chordates. Chordates are animals that have a notochord, a dorsal nerve cord, and pharyngeal slits. The first vertebrates were fish, which evolved around 500 million years ago. Fish gave rise to amphibians, which evolved around 350 million years ago. Amphibians gave rise to reptiles, which evolved around 300 million years ago. Reptiles gave rise to birds, which evolved around 150 million years ago. Mammals evolved from a group of reptiles called the synapsids around 200 million years ago.
Vertebrates have been very successful in adapting to a wide variety of environments. They can be found in all parts of the world, from the deepest oceans to the highest mountains. Vertebrates play an important role in the ecosystem, as they are both predators and prey. They are also a source of food and medicine for humans.