The coelomate body plan is a "tube within a tube". Evolutionary advantages of coelom can be outlined as follows :ġ. It lies between the outer body wall of epidermal tissue and the gut or digestive tract. Why was the development of a true coelom such an important step in the evolution of higher animals?Ī true coelom is a fluid-filled body cavity formed from mesodermal tissue. These pockets gradually expand to form the coelom.Įnterocelous development is advance in comparison to schizocoelous development due to the formation of the archenterons.ģ. The stage starts with the gastrula as the archenteron forms, pockets of migrating cells also form, creating another layer between the endoderm and ectoderm, the mesoderm. Describe the enterocoel hypothesis of coelom origin and discuss the implications.Įnterocoelous development is the stage of embryological development of deuterostomes in which the coelom forms. Phyla Mollusca, Annelida, Arthropoda and others Phyla Echinodermata, Hemichordata, Chordata and otherĢ.
Spiral, determinate cleavage at 4 -> 8 cell division radial, indeterminate cleavage at 4 -> 8 cell divisionĬirculatory system primitively dorsal and nervous system primitively ventral circulatory system primitively ventral and circulatory system primitively ventral Thanks for using Brainmass.ġ.Compare and contrast the protostomes and deuterostomes.īlastopore becomes mouth & 2nd opening becomes anusělastopore becomes anus & 2nd opening becomes mouthĬoelom formed via schizocoelyĜoelom formed via enterocoely
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