Question

Segmentation first evolved in the organisms of phylum Annelida, and vertebrates evolved more recently. How does the vertebrate body plan display segmentation and what are some associated benefits?

I got this question wrong. Could someone help me understand the correct answer and reasoning.

Answer 1

• Phylae of kingdom Animalia like Annelidae, Arthropoda as well as Chordata have segmented body plan.
• In the development of vertebrates, a 3 segmented plan is organized: rhombomeres, pharyngeal arches as well as somites, which all have succession of newer growth from the longer axis.
• Various anataomical and morphological developments are resulted from various segmented system so as to have specific assigned functions
• Segmentation in paraxial mesoderm aids to the lateral movement related organs. Eg. Fish
• Segmentation in hind brain develops the seamless communication in the neuronal system.
• Segmentation in pharyngeal arches results in the evolution of complicated respiratory apertures and required vascular network.
• In vertebrates the segmentation is different in 3 categories aiding in contrasting functions after development.
• Gene expression studies also highlights the complexity of vertebrates when compared to other lower groups. The segmentation in the lower phylae were in the primitive stage and the evolution and development of animalia kingdom with vertebrates actually shows the evolution in the segmentation too, as from simple Annelids to complex vertebrates.

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