236 Understanding the Neoproterozoic Earth-Life System

Wednesday, 25 September 2019
8:00 AM - 12:00 PM
North Ballroom 120D, North Building

GENERATING DEVELOPMENTAL CAPACITY DURING AN INTERVAL OF INTENSE ENVIRONMENTAL CHANGE: THE EARLIEST HISTORY OF ANIMALS

Paper number: 236-9
Program: Technical Sessions
Time: 10:40 AM – 11:00 AM

Authors

Abstract

The capacity for multicellular development and the generation of the cell types, developmental patterning and complex morphologic and behavioral attributes of animals required a suite of changes in cellular gene regulation and development associated with the origin and early evolution of animals. Comparative studies of the development of extant animals and their closest relatives (choanoflagellates, filastreans and ichthysporeans) has revealed that many components of developmental regulation originated prior to the origin of animals, possibly for the control of the various cell types required by complex life cycles. The novelties in metazoan developmental genes and processes novelties area associated with the formation of genome control mechanisms, developmental tools and developmental patterning, but do not appear to have been immediately associated with complex spatial patterning. Understanding the expansion of regulatory and developmental capacity requires consideration of their origin during an interval of intense environmental change. In particular, changes in the levels and stability of oxygen in shallow marine environments have been invoked as causal drivers. Integrating developmental, genomic and fossil data with the environmental context strongly supports a model of early metazoans of many cell types but relatively flat regulatory hierarchies and limited morphogenic patterning. Although some amount of genome expansion was involved, co-option of existing regulatory machinery for new purposes was pervasive as various eumetazoan lineages acquired the morphologic novelties needed for the larger body sizes associated with the Ediacaran-Cambrian ‘explosion’ documented by the fossil record.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-333649

© Copyright 2019 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.