Introduction
Lophophorates and Echinoderm are marine invertebrates with distinguishable general characteristics, mobility, and role in the ecosystem, among other features. In comparison, Lophophorates are aquatic vertebrates with a lophophore and ciliated tentacles around the mouth to filter food from the water. Marine vertebrate animals of the phylum Echinodermata are characterized by spiny and hard skin. Echinoderm has major distinguishing characteristics of a five-sided symmetry shape and a water vascular system and includes sea stars, sea urchins, cucumbers, and crinoids. Contrastingly, sponges, cnidarians, and ctenophores are Lophophorates defined by u-shaped circles of tentacles. Comparing the general characteristics, feeding habits, mobility, role in the ecosystem, and embryological development features between Lophophorates and Echinoderm indicates major differences and some similarities.
Main body
Lophophorates are believed to be the first animals to develop the nervous system while Echinoderm is thought to be the first group to develop radial symmetry. The organization of the nervous and muscular system in the lophophore has undergone substantial evolution with two main modifications. Extension of the second accessory brachial nerve was the first modification that triggered the second modification (Slota et al., 2019). Notably, the neuron system evolved from metazoans, particularly Cnidarians, with the simplest nervous system to mammals. Therefore, Lophophorates have experienced incomparable evolution and are considered the first to develop the nervous system.
Evolving from a common bilaterally symmetric ancestry, the Echinoderm were the first group of animals to develop a radially configured body structure. In effect to symmetry, radial symmetry was the first to evolve, followed by bilateral symmetry. The Cnidarian was the first to display radial symmetry in their body structure since bilateral symmetry can be observed at larvae stages of development that disappear once they develop to radial symmetry in adulthood. Moreover, radial symmetry is mostly needed by the Echinodermata group of aquatic vertebrates to increase the surface area of extracting food from the surrounding environment. Since radial symmetry led to the development of bilateral symmetry, and the Cnidarians display bilateral symmetry at larvae stages that disappear in adulthood, the Echinodermata were the first to develop radial symmetry. Lophophores and Echinoderm are vital in the ecosystem by facilitating the initial development of the nervous system and the radial symmetry, respectively.
Comparing the feeding and mobility characteristics between Lophophorates and Echinoderm indicates differences. While the former relies on lophophores, the latter relies on tube feet for locomotion and feeding. Lophophorates are a pair of spiral feeding structures filled with ciliated tentacles that trigger water currents that deposit food particles towards the mouth to facilitate feeding and respiration. At the larval stage, Echinoderms utilize pluteus, a bilateral symmetry to propel and draw water towards the body leading to forward or upward swimming. Upon development to adulthood, the Echinoderm develops radial tube feet elemental for grabbing food, movement, and respiration. Echinoderm is benthic since it uses tube feet to feed and crawl along the ocean floor, unlike Lophophorates, which filter food particles from the water. However, Lophophorates are sessile, implying they have limited locomotion compared to Echinoderm, which uses the projections on the tube feet to crawl around the surface of a water body.
All Echinoderm are triploblastic different from Lophophorates which only sponges are triploblastic, while Cnidarians and ctenophores are diploblastic. Essentially, Echinoderm and sponges have three cellular layers comprising the ectoderm, mesoderm, and endoderm contrast to cnidarians and ctenophores that do not have a mesodermal layer. The mesodermal layer specializes and transforms to give rise to lost body parts, tissues, skeletal muscles, and the digestive tract. Contrarily, the cnidarians and ctenophores utilize asexual reproduction to regenerate lost tissues and body parts which is the fragmentation of the body into two or more parts. Moreover, the coelom, a cavity in the mesodermal layer of the triploblastic Echinoderm, is modified to the water vascular system. Since Lophophorates do not have a water vascular system, they lack a true body cavity apart from sponges with coelomic fluid.
Marine invertebrates can either be classified as deuterostomes or protostomes. Animals of phyla Echinodermata can be classified together with deuterostomes, whereas those of phyla Lophophorata can be grouped with protostomes. In protostomes, the blastophore develops to be a mouth opening, different from deuterostomes, where it develops into an anal opening (Gaunt, 2018). Consequently, Echinoderm has anal openings similar to other deuterostomes invertebrates distinct from protostomes like Lophophorates with mouth openings.
Conclusion
From the analysis, marine life, either vertebrates or invertebrates, can be classified according to; general characteristics, symmetrical formation, mobility, feeding habits, and embryological formation. Ultimately, the summary explores the relationship between Lophophorates and Echinoderm phylum according to biological classification standards crucial for studying other marine life.
References
Gaunt, S. J. (2018). Hox cluster genes and collinearities throughout the tree of animal life. International Journal of Developmental Biology, 62(11-12), 673-683. Web.
Slota, L. A., Miranda, E. M., & McClay, D. R. (2019). Spatial and temporal patterns of gene expression during neurogenesis in the sea urchin Lytechinus variegatus. Evodevo, 10(1), 1-16. Web.