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Echinoderms Have Bilateral Tendencies

Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. Durin...

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Autores principales: Ji, Chengcheng, Wu, Liang, Zhao, Wenchan, Wang, Sishuo, Lv, Jianhao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256158/
https://www.ncbi.nlm.nih.gov/pubmed/22247765
http://dx.doi.org/10.1371/journal.pone.0028978
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author Ji, Chengcheng
Wu, Liang
Zhao, Wenchan
Wang, Sishuo
Lv, Jianhao
author_facet Ji, Chengcheng
Wu, Liang
Zhao, Wenchan
Wang, Sishuo
Lv, Jianhao
author_sort Ji, Chengcheng
collection PubMed
description Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present.
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spelling pubmed-32561582012-01-13 Echinoderms Have Bilateral Tendencies Ji, Chengcheng Wu, Liang Zhao, Wenchan Wang, Sishuo Lv, Jianhao PLoS One Research Article Echinoderms take many forms of symmetry. Pentameral symmetry is the major form and the other forms are derived from it. However, the ancestors of echinoderms, which originated from Cambrian period, were believed to be bilaterians. Echinoderm larvae are bilateral during their early development. During embryonic development of starfish and sea urchins, the position and the developmental sequence of each arm are fixed, implying an auxological anterior/posterior axis. Starfish also possess the Hox gene cluster, which controls symmetrical development. Overall, echinoderms are thought to have a bilateral developmental mechanism and process. In this article, we focused on adult starfish behaviors to corroborate its bilateral tendency. We weighed their central disk and each arm to measure the position of the center of gravity. We then studied their turning-over behavior, crawling behavior and fleeing behavior statistically to obtain the center of frequency of each behavior. By joining the center of gravity and each center of frequency, we obtained three behavioral symmetric planes. These behavioral bilateral tendencies might be related to the A/P axis during the embryonic development of the starfish. It is very likely that the adult starfish is, to some extent, bilaterian because it displays some bilateral propensity and has a definite behavioral symmetric plane. The remainder of bilateral symmetry may have benefited echinoderms during their evolution from the Cambrian period to the present. Public Library of Science 2012-01-11 /pmc/articles/PMC3256158/ /pubmed/22247765 http://dx.doi.org/10.1371/journal.pone.0028978 Text en Ji et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Ji, Chengcheng
Wu, Liang
Zhao, Wenchan
Wang, Sishuo
Lv, Jianhao
Echinoderms Have Bilateral Tendencies
title Echinoderms Have Bilateral Tendencies
title_full Echinoderms Have Bilateral Tendencies
title_fullStr Echinoderms Have Bilateral Tendencies
title_full_unstemmed Echinoderms Have Bilateral Tendencies
title_short Echinoderms Have Bilateral Tendencies
title_sort echinoderms have bilateral tendencies
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256158/
https://www.ncbi.nlm.nih.gov/pubmed/22247765
http://dx.doi.org/10.1371/journal.pone.0028978
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AT lvjianhao echinodermshavebilateraltendencies