What are vertebrates?

vertebrates are animals with spine, also known as the backbone column. They create most of the phylum chordata, one of the 38 animal phyla. All other phyla are exclusively invertebrate. A few members of the phylum Chordata, Lancelet and Tunicates are invertebrates. Lancelet only has a Notochord rather than a real spinal Coumn and Tunicates have a Notochord during early development. Fish, sharks, rays, amphibians, reptiles, birds and mammals (including people) are vertebrates. The spinal column also acts as a super -shaping boundary for the nervous system and promotes greater complexity. The first vertebrates are known from fossils in Maotianshan Shales in China, dated between 525 and 520 million years, during an episode of adaptive radiation called Cambrian Explosion. They are simple fish without a jaw like myllocunmingia , carrying a superficial similarity to modern hagfishes. These fish precede other fossils of vertebrates by about 30 million years.

among the vertebrates were the first fish to evolve the limbs and began to walk on the ground and became amphibians. Many amphibians developed a scaly skin and amniotic eggs and became Plazimi, the first line of vertebrates to colonize continental interiors. On Earth, the evolutionary vertebrate strategy is particularly successful in all animals larger than a few cm, which must have sufficient structural integrity to support their own weight. For this reason, the largest ground animals are vertebrates for hundreds of millions of years. Recently, cetaceans (whales, developing 50 million years ago from land animals) were the largest animals of the seas, so vertebrates form the largest animals both on the land and at sea.

vertebrates are named for their vertebrae, segmented parts of the spine. These segmented sections give the spine some flexibility while maintaining its strength. Vertebrae are surrounded by nerve fibers that give orders through electric SigMoods, from the brain to all limbs. If vertebrates have a broken spine, they usually die, although people have developed forms of surgery to repair the broken spine if the damage is not too large.