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Colonial Life-history: A Major Evolutionary Transition, Involving Modularization of Multicellular Individuals and Heterochrony (Miniaturization and Adultation)

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Stefania Gutierrez^*

This version is not peer-reviewed

Submitted:

15 August 2020

Posted:

20 August 2020

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Abstract

The diversification of life-histories is mediated by cooperation, innovations of biological information, modularity, and heterochrony in developmental processes. These processes are defined, contextualized, and exemplified, studying the evolution of coloniality (i.e. life-history involving modularization of the multicellular individual) in the family of benthic tunicates Styelidae. This study proposes that in these colonial tunicates there is an inter-generational division of labor, where one generation is feeding, a second is developing by morphogenetic processes, and a third is aging by programmed cell death and phagocytosis. The communication system developed in these colonies is mediated, by changes in proportion, location, and gene expression of specialized blood cells. Colonial life-history in animals is related to the reduction of individual size; development of extra-corporeal tissues to interconnect zooids; the inter-generational division of labor; and the reduction of zooid’s individuality. Processes analogous with the widely accepted major evolutionary transitions (METs), suggesting that coloniality could be studied as a MET. The understanding of colonial life-histories could provide information about key mechanisms for life diversification.

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Subject: Biology and Life Sciences - Animal Science, Veterinary Science and Zoology

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