Two of life’s three domains, the Bacteria and Archaea, diversified on the early Archean Earth. The third domain – the Eukarya, or eukaryotes – evolved later, however, at least in part via symbiosis between members of the other great clades.  Eukaryotic organisms radiated in Proterozoic oceans characterized by oxygenated surface waters, but, commonly, anoxia at depth.  Exceptionally preserved fossils of red algae favor crown group emergence more than 1200 million years ago, but older (up to 1600-1800 million years) microfossils record a moderate diversity of stem- or early crown-...

The title of Andy's lecture is "The Deep History of Life."  The lecture is hosted by UC Riverside's College of Natural and Agricultural Sciences and the new Environmental Dynamics and GeoEcology Institute.

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Lecture by Dimitar Sasselov at the Simons Foundation in New York, NY. For more details, click here.

Raymond Pierrehumbert
Dept. of the Geophysical Sciences
University of Chicago

In Earth's present climate, the condensible component (water vapor) makes up only a small part of the mass of the atmosphere, so energy transport by condensate is small and the effect of condensation on surface pressure is slight. We refer to this as the dilute condensable case. Climate dynamics for the nondilute case engages a number of entirely novel phenomena, which cannot be treated within conventional terrestrial-type general circulation models.  Nondilute climate dynamics is...

John Chaput
The Biodesign Institute at Arizona State University

Life presumably arose through a series of discrete steps in which chemical systems gave rise to unicellular organisms with DNA genomes and protein enzymes. As we study the path from chemistry to biology, several interesting scientific questions arise that are worthy of experimental investigation....

John Johnson
Department of Astronomy
Harvard University

Just three years ago the prospect of finding temperate, rocky worlds around other stars was still the subject of science fiction: none had been found and reasonable estimates put us years or decades away from such a momentous discovery. All of that has changed very recently on the heels of the extraordinarily successful NASA Kepler mission. By searching for the tiny diminutions of starlight indicative of an eclipsing planet, Kepler has produced thousands of new planet candidates orbiting distant stars. Careful statistical...

Peter Girguis
Dept. of Organismic & Evolutionary Biology
Harvard University

Microbes are, unquestionably, the most critical members of our biosphere. They exist in every habitat, playing a role in mediating atmospheric and ocean composition and governing elemental cycles in soils and sediments. The last two decades have been a watershed for  microbiology, with major advances in genomic sequencing and other technologies that have fundamentally changed our view of microbial diversity and evolution. However, our understanding of what microbes are doing...

Tanja Bosak
Dept. of Earth, Atmospheric & Planetary Sciences
Massachusetts Institute of Technology

Mineral precipitation, sedimentation and microbial activity have shaped landscapes in coastal environments for nearly 3.5 billion years, forming stromatolites and other sedimentary structures.  The shapes and textures of these structures may record  evolutionary and chemical changes during the first  80% of Earth's sedimentary history. However, as complex products of physical processes, microbial ecology,...

Laura Landweber  
Dept. of Ecology & Evolutionary Biology
Princeton University

The unicellular eukaryote Oxytricha trifallax has an extremely dynamic pair of genomes, with massive DNA rearrangements producing a highly fragmented, somatic genome from a germline genome roughly twenty times its sequence complexity. During development, Oxytricha eliminates nearly all its noncoding DNA, including all its transposons, and rearranges the ~225,000 remaining DNA pieces to produce functional genes. In the precursor, germline genome, the scattered segments of different genes...

David Deamer
Department of Biomolecular Engineering
University of California, Santa Cruz

The pathway leading to the origin of life presumably included a process by which polymers were synthesized abiotically from simpler compounds on the early Earth, then encapsulated to form protocells. Previous studies have reported that mineral surfaces can concentrate and organize activated mononucleotides, thereby promoting their polymerization into RNA-like molecules. However, a plausible prebiotic activation mechanism has not been established, and minerals cannot form cellular...

Martin Nowak (Harvard University)

Irene Chen (Harvard Medical School & FAS Center for Systems Biology)

Ronald Breaker (Yale University)

George Cody (Carnegie Institution, Washington, DC)