What are deuterostomes?

Deuterostomes are a large superfylum of animals that include chords (vertebrates), echinoderma, hemichordates (worms acorn) and one small phyla, xenoturbuhllid, consisting of two types of sea worms. "Deuterosome" means "the organism of the second mouth", "reference to the fact that during embryological development in deuterostomes the first opening of the body becomes the rectum and the second mouth, unlike the sciences where the opposite is. The science that has all animals above a certain level of complexity will probably be deuterostomas, for example, all the animals are the advantage of deuterostomes.City for the muscles they can pull against, and also allow the development of more complex organs whose structural development is independent of the development of the wall of the body.

Many of the simplest deuterostomes have three simple properties - slits, hollow nerve cord and segmented body. It seems likely that the common predecessor of all deuterostomas had these features. There is some uncertainty where deuterostomes branched from the schedules, but many paleontologists are considered a probable lower limit 558 million years ago. ernettia , Fossil from the late Ediacaran period seems to be a probable deuterostoma, while the mysterious extinct Phylum from the firstcambrian, vetulicolia, has functions that indicate that they were deuterostomas.

Over 20 million years, the earliest simple deuterostomas developed on the first vertebrate - especially fish without jaws that are ancestors of all fishLoos and earthly vertebrates. Many of the Spinoff groups still exist to this day - xenoturbation, worms of acorns, tunics, Lancelet, etc. Tunicates are one of the most unusual of these groups as their larvae from the nervous line, but loses it in adulthood. This raises the possibility that vertebrates have evolved from the larvae form of certain invertebrates.