Wonderful Ediacarans, wonderful cnidarians?

  title={Wonderful Ediacarans, wonderful cnidarians?},
  author={Douglas H. Erwin},
  journal={Evolution \& Development},
  • D. Erwin
  • Published 1 May 2008
  • Environmental Science
  • Evolution & Development
In Wonderful Life, Stephen Jay Gould (1989) argued that the morphological range of arthropods recovered from the Middle Cambrian Burgess Shale fauna in British Columbia demonstrated that morphologic diversity increased more rapidly than taxonomic diversity. As was so often the case with Steve, he was directly challenging what he viewed as the unjustified assumptions of traditional evolutionary theory. Gould’s claim initially generated considerable controversy (Briggs et al. 1992), but Wonderful… 

Ancestral state reconstruction of ontogeny supports a bilaterian affinity for Dickinsonia

This study formalizes the connection between ontogeny in Dickinsonia—which grows by the addition of metameric units onto one end of its primary axis—with terminal addition, defined as growth and patterning from a posterior, subtermial growth zone, and concludes that terminal addition is a synapomorphy of bilaterian animals.

The origin of the animals and a ‘Savannah’ hypothesis for early bilaterian evolution

  • G. BuddS. Jensen
  • Environmental Science, Geography
    Biological reviews of the Cambridge Philosophical Society
  • 2017
The subtle remnants of Ediacara‐style taxa within the Cambrian suggest that they remained significant components of Phanerozoic communities, even though at some point their enabling role for bilaterian evolution was presumably taken over by bilaterians or other metazoans.

On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota.

Haootia quadriformis n. gen., n. sp., interpreted as a muscular cnidarian impression from the Late Ediacaran period (approx. 560 Ma)

Haootia quadriformis potentially provides the earliest body fossil evidence for both metazoan musculature, and for Eumetazoa, in the geological record.

Ecospace Utilization During the Ediacaran Radiation and the Cambrian Eco-explosion

A theoretical ecospace is a multi-parameter system for classifying the ecological properties of organisms; because they are viewed in terms of their ecological and functional capabilities,

The origin of the Hox/ParaHox genes, the Ghost Locus hypothesis and the complexity of the first animal.

  • D. Ferrier
  • Biology
    Briefings in functional genomics
  • 2016
Reassessments of the diversity and complexity of developmental control genes in the earliest animal ancestors need to go hand-in-hand with complementary advances in comparative morphology, phylogenetics and palaeontology to clarify the complexity of the last common ancestor of all animals.

Stem cell dynamics in Cnidaria: are there unifying principles?

Self-renewal and transdifferentiation of epithelial cells was probably more important to ancestral cnidarian development than any undifferentiated cell lineage, and only later in evolution did one or more cell types come under the regulation of a “stem” cell line.

Predation and the Origin of Neurones

Fossils suggest that animals evolved nervous systems soon after the advent of animal-on-animal predation, 550 million years ago (MYa), and genetic evidence testifies that nervous systems evolved before the protostome-deuterostome split.

The Evolutionary Origin of Nervous Systems and Implications for Neural Computation

This thesis argues that the first afferent sensory neurones were threshold detectors that produced spikes to alert animals of the proximity of other animals, and that animals evolved nervous systems soon after they started eating each other, 550 million years ago.



The Ediacaran Biotas in Space and Time1

  • B. Waggoner
  • Environmental Science, Geography
    Integrative and comparative biology
  • 2003
It is concluded that the Ediacaran organisms show a diverse range of responses to various environmental parameters, and there is no basis for classifying them all as having a single body plan and mode of life.

The Avalon Explosion: Evolution of Ediacara Morphospace

A comprehensive quantitative analysis of these fossils indicates that the oldest Ediacara assemblage—the Avalonassemblage (575 to 565 Ma)—already encompassed the full range of Ediacar morphospace.

Rising starlet: the starlet sea anemone, Nematostella vectensis.

The traits that make Nematostella exceptionally attractive as a model organism are explored, recent research demonstrating the utility of Nem atostella in several different contexts are summarized, and a number of developments likely to further increase that utility in the near future are highlighted.


  • D. Erwin
  • Environmental Science, Geography
  • 2007
Concern with disparity is a question about temporal variation in the production of morphological innovations, a debate over the relative significance of the generation of new morphologies vs. differential probabili- ties of their successful introduction, and the relative importance of constraint, convergence and contingency in the evolution of form.


Quantitative morphological studies reveal profound changes in evolutionary rates corresponding with the generation of morphological disparity at low taxonomic diversity during the early radiation of many clades.

Morphological disparity in the cambrian.

An analysis of the range of morphology among arthropod demonstrates that disparity among living arthropods is similar to that in Cambrian arthropoda, suggesting that special evolutionary processes may not be necessary to explain the early radiation of the metazoans.

Sea Anemone Genome Reveals Ancestral Eumetazoan Gene Repertoire and Genomic Organization

A comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis, suggests that gene “inventions” along the lineage leading to animals were likely already well integrated with preexisting eukaryotic genes in the eumetazoan progenitor.

Hox, Wnt, and the evolution of the primary body axis: insights from the early-divergent phyla

The hypothesis that Wnt genes may be the earliest primary body axis patterning mechanism by suggesting that Hox genes were co-opted into this patterning network prior to the last common ancestor of cnidarians and bilaterians is extended.

A WNT of things to come: evolution of Wnt signaling and polarity in cnidarians.

This wonderful life

A young woman mourning the death of her husband takes a walk into the countryside, feeling alone and withdrawn from life. Her sense of isolation is lifted when she discovers, beneath a bridge, an