I.—<i>Observations upon Professor Ernst Haeckel's group of the “Physemaria,” and on the affinity of the sponges</i>

Kent, W. Saville

doi:10.1080/00222937808682283

Cited by 9 publications

(6 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Codosiga pulcherrima (57), Monosiga gracilis (58), and the sessile form of C. perplexa (7), the sister-species of C. flexa. As part of this study, we observed collar contractions in C. flexa sheets (Fig.…”

Section: The Ancestry Of Apical Constrictionmentioning

confidence: 99%

Light-regulated collective contractility in a multicellular choanoflagellate

Brunet

Larson

Linden

et al. 2019

Science

134

171

View full text Add to dashboard Cite

Collective cell contractions that generate global tissue deformations are a signature feature of animal movement and morphogenesis. However, the origin of collective contractility in animals remains unclear. While surveying the Caribbean island of Curaçao for choanoflagellates, the closest living relatives of animals, we isolated a previously undescribed species (here named Choanoeca flexa sp. nov.) that forms multicellular cup-shaped colonies. The colonies rapidly invert their curvature in response to changing light levels, which they detect through a rhodopsin–cyclic guanosine monophosphate pathway. Inversion requires actomyosin-mediated apical contractility and allows alternation between feeding and swimming behavior. C. flexa thus rapidly converts sensory inputs directly into multicellular contractions. These findings may inform reconstructions of hypothesized animal ancestors that existed before the evolution of specialized sensory and contractile cells.

show abstract

Section: The Ancestry Of Apical Constrictionmentioning

confidence: 99%

Light-regulated collective contractility in a multicellular choanoflagellate

Brunet

Larson

Linden

et al. 2019

Science

134

171

View full text Add to dashboard Cite

show abstract

“…Saville-Kent's hostility toward Haeckel often got personal, and his comments onHaeckel's work contained a surprising density of personal attacks (e.g (Kent 1878)(Leadbeater 2015)).…”

mentioning

confidence: 99%

The Single-Celled Ancestors of Animals: A History of Hypotheses

Brunet¹,

King²

2020

Preprint

View full text Add to dashboard Cite

Animals, with their complex and obligate multicellularity, evolved from microbial eukaryotes that were likely obligately or facultatively unicellular. The nature of the unicellular progenitors of animals has intrigued biologists since the late 19th century, coinciding with the parallel spread of the cell theory and the theory of evolution. However, views on the ancestry of animals have been extremely varied. The huge diversity of single-celled organisms, the tremendous plasticity of animal cellular phenotypes, and the difficulties of organizing both into clear phylogenies in the pre-molecular era allowed a wide range of hypotheses to flourish, with nearly every major single-celled lineage, at one time or another, having been proposed as the precursor of animals. Most of these hypotheses never gained followers beyond their originator (such as the ideas that animals evolved directly from either bacteria, Volvox or fungi) and will not be discussed here. Three concepts, however, have been enduring and influential: (1) the amoeboid theory; (2) the flagellate theory; and the (3) the ciliate theory – to which a fourth category can now be added: (4) a mixed model, in which the ancestor was phenotypically plastic. We will discuss their origin, history, and current relevance.

show abstract

“…By contrast, collective contractility and apical constriction were hitherto unknown in close relatives of animals, making their origin mysterious.The existence of actomyosin-mediated apical constriction in C. flexa raises the possibility that this cellular module might have been present in the last common ancestor of choanoflagellates and animals (which together comprise the choanozoans (1)). Collar contractions have been reported in the unicellular stages of three other choanoflagellate species:Codosiga pulcherrima (57), Monosiga gracilis(58), and the sessile form of C. perplexa(7), the sister-species of C. flexa. As part of this study, we observed collar contractions in C. flexa sheets (Fig.…”

mentioning

confidence: 99%

Light-regulated collective contractility in a multicellular choanoflagellate

Brunet

Larson

Linden

et al. 2019

Preprint

View full text Add to dashboard Cite

Collective cell contractions that generate global tissue deformations are a signature feature of animal movement and morphogenesis. Nonetheless, the ancestry of collective contractility in animals remains mysterious. While surveying the Caribbean island of Curaçao for choanoflagellates, the closest living relatives of animals, we isolated a previously undescribed species (here named Choanoeca flexa sp. nov.), that forms multicellular cup-shaped colonies. The colonies rapidly invert their curvature in response to changing light levels, which they detect through a rhodopsin-cGMP pathway. Inversion requires actomyosin-mediated apical contractility and allows alternation between feeding and swimming behavior. C. flexa thus rapidly converts sensory inputs directly into multicellular contractions. In this respect, it may inform reconstructions of hypothesized animal ancestors that existed before the evolution of specialized sensory and contractile cells. One Sentence Summary:A newly described choanoflagellate species forms cup-shaped colonies that reversibly invert their curvature in response to light.

show abstract

I.—Observations upon Professor Ernst Haeckel's group of the “Physemaria,” and on the affinity of the sponges

Cited by 9 publications

References 1 publication

Light-regulated collective contractility in a multicellular choanoflagellate

Light-regulated collective contractility in a multicellular choanoflagellate

The Single-Celled Ancestors of Animals: A History of Hypotheses

Light-regulated collective contractility in a multicellular choanoflagellate

Contact Info

Product

Resources

About