Convening a session at EGU Vienna 2018

Together with such excellent colleagues from the Precambrian geology field as Graham Shields, Daniel LeHeron and Sebastian Viehmann I am convening a session of biogeochemistry and evolution from the Archean to the Neoproterozoic. The preliminary session abstract is:

Palaeoenvironments of the Precambrian World:

from the Archean via Snowball Earth and beyond

Fundamental key parameters to understand the evolution of life and Earth's habitats involve the interaction between the atmos-, hydros- and biospheres. For instance, the redox- evolution and the geodynamical evolution during Precambrian times played a fundamental role in shaping ancient environments. In this session we invite contributions from combined fields of sedimentology, (bio)geochemistry, numeric modelling, palaeontology and geophysics, ranging in the timeframe from the origin of life until Snowball Earth and beyond. We discuss the (co-)evolution of the atmosphere, biosphere and oceans and also try to understand how much better the Neoproterozoic glaciations are constrained since the last 20 years and what the sedimentary record offers to understand the behaviour of the ancient ice masses, and how it compares to Phanerozoic sedimentary successions.

 

hope to see you all at EGU this spring

 

groundbreaking new hypothesis on why life diversified on Earth after the Cambrian explosion

'Refined control of cell stemness allowed animals to evolve in the oxic realm' by Emma U. Hammarlund, Kristoffer von Stedingk and Sven Påhlman

Abstract

Animal diversification on Earth has long been presumed to be associated with the increasing extent of oxic niches. Here, we challenge that view. We start with the fact that hypoxia (<1–3% O2) maintains cellular immaturity (stemness), whereas adult stem cells continuously—and paradoxically—regenerate animal tissue in oxygenated settings. Novel insights from tumour biology illuminate how cell stemness nevertheless can be achieved through the action of oxygen-sensing transcription factors in oxygenated, regenerating tissue. We suggest that these hypoxia-inducible transcription factors provided animals with unprecedented control over cell stemness that allowed them to cope with fluctuating oxygen concentrations. Thus, a refinement of the cellular hypoxia-response machinery enabled cell stemness at oxic conditions and, then, animals to evolve into the oxic realm. This view on the onset of animal diversification is consistent with geological evidence and provides a new perspective on the challenges and evolution of multicellular life.

source: Nature Ecology and Evolution