David Gold, a post-doc in the Summons lab at MIT, is the lead author of a new paper in Nature –Paleoproterozoic sterol biosynthesis and the rise of oxygen. His findings suggest that eukaryotic organisms were present on Earth as early as 2.31 billion years ago, around the same time that oxygen was first present in the Earth’s atmosphere. This finding significantly pushes back the earliest signs of eukaryotes. Previously, the oldest known eukaryotes were algae-like fossils from 1.56 billion years ago.
David and his co-authors arrived at this conclusion by doing a molecular clock analysis of the genes associated with sterol biosynthesis. They constrained their molecular clock with fossil evidence and used multiple molecular clock analyses. These analyses constrained the evolution of sterol biosynthesis to approximately 2.31 billion years ago. Complex sterols are unique to eukaryotes and producing them is an oxygen-intensive process. Therefore, these biomarkers are evidence of both eukaryotic life and an oxygenated atmosphere. Previously, it appeared that the evolution of sterol biosynthesis lagged behind the oxygenation of the atmosphere. However, this study suggests that this evolutionary event is tied to the availability of oxygen in the atmosphere.
Phoebe Cohen (Williams) recently started an excellent new podcast “Female of the Species.” It is a podcast about “the sisterhood of science. A healthy mix of issues facing women in STEM, good solid chit chat, and belly laughs.” It is an absolutely wonderful podcast and I suggest checking it out!
The Briggs lab dug into a nearly 50-year old mystery when they began investigating the Tully monster (Tullimonstrum gregarium) – an animal found in 300 million year old coal deposits in northeastern Illinois. This oddly-shaped animal was an enigma because it could not be assigned to a phylum. The team studied nearly 2,000 fossils over the course of their study and concluded that The “Tully Monster” is a Vertebrate.
Lidya Tarhan, a post-doc in the Briggs lab at Yale, is first author of a new paper published in Nature Geoscience – Protracted Development of bioturbation through the early Plaeozoic Era. This work from Lidya, members of the Briggs Lab, and collaborators, indicates that marine animals took significantly longer than previously thought to commence major bioturbation (burrowing and mixing) of marine surface sediments. Rather than the Cambrian (541 Ma) as previously thought, they propose that this happened much later during the Silurian (~420 Ma). This has potentially broad implications sulfate and oxygen levels in the oceans during this time, for the our understanding of Earth’s ancient ecosystems.
Here is a link to a news story titled ‘Ancient dirt churners took their time stirring up the ocean floor’
The Briggs Lab took part in the Yale department field trip this August. The trip involved a performing a transect across the Alps and Apennines from Frankfurt, Germany to Assisi, Italy.
For over two weeks in August, 23 students and faculty travelled about 3000 km and covered the amazing sedimentary record preserved between the mountains belts between Germany, Switzerland and Italy.
New research from the Briggs Lab reporting on the oldest known eurypterid fossils from Iowa was recently published in BMC Evolutionary Biology. Eurypterids were large aquatic arthropods, that are ancestors to modern spiders and lobsters, for example. This new species, called Pentecopterus, lived about 467 Ma, during the Ordovician. Despite the age of this fossil, remarkable preservation was observed. Here is a link to some other media coverage. This research involved collaboration between Yale and the University of Iowa.
Earlier in August, the Briggs Lab published a paper in Biology Letters titled ‘All the better to see you with‘ reporting on the visual system of the eurypterids and the divergent ecological roles between a number of these species. This was a follow-up paper to ‘What big eyes you have‘, published last year. Looking forward to the next paper!
Briggs Lab graduate student Ross Anderson has been working in the Tosca Lab in Oxford recently. He has been using using X-ray diffraction to study clay minerals from Neoproterozoic fossils of exceptional organic preservation (called ‘lagerstatten’). His goal is to try to understand the processes and mechanisms of organic microfossil preservation and to reconstruct the biology, and environmental conditions and perturbations of the Neoproterozoic.
Members of the Summons Lab represented Foundations of Complex Life in force again at this year’s Cambridge Science Festival. We brought our research to the general public at two of the countless events during the festival, the “Science Carnival and Robot Zoo” held during the first Saturday of the festival, and “Soaring into Sky and Space” at the MIT Museum during the second Saturday. Turnout for both events was excellent—with a constant stream of curious minds, young and old, piling up several faces deep at our booths for the duration of each event.
Scenes from FCL’s booth at the MIT Museum for the “Soaring into Sky and Space” event. First three photos courtesy of the MIT Museum.
Coffee filters were among the most popular parts of our booth at the MIT Museum. Why coffee filters, you ask? Well, our booth featured many of the physical objects of our research, from the rocks we collect in the field and the hammers we use to collect them, to the glassware and pieces of analytical instruments we use to extract and identify organic chemicals within those rocks. An important part of the process from rocks to chemicals is chromatography, the separation of chemical compounds. To illustrate this process, we gave visitors to our booth the chance to do a quick, hands-on chromatography experiment themselves, separating the pigments in an ink marker using a coffee filter and few drops of water. The demonstration was a hit, and it was a pleasure to see so many delighted “aha” expressions on the faces of both children and their parents over the course of the day.
At the “Science Carnival and Robot Zoo”, we debuted a multiplayer version of our successful iPad game “Earth in Sixty Seconds”. The game compresses four and a half billion years of Earth history into a single minute, letting players become high-speed time travelers and race through the geologic ages at breakneck speed. Using iPod touch controllers, player guessed the timing of key events in the history of our planet, and the life that evolved on it. When did life originate? When did dinosaurs go extinct, and humans evolve? Although many visitors to our booth had an inkling that human history occupied a short time at the end of our countdown (much, much less that one second!), many were surprised at how recently animals (just the last seven seconds) and even oxygen in the atmosphere (only the second half of the minute) appeared in our planet’s history.
Attendees of the Executive Council meeting in front of the Gemini 11 space capsule at the California Science Center.
Foundations of Complex Life principal investigator Roger Summons joined the PIs of the other NAI Teams, including the new teams selected during the CAN7 competition, for an in-person meeting hosted by the USC team in Los Angeles last week. As a part of the onboarding process for the new teams, each team gave a brief overview and introduction to their research. You can download and view the MIT Team’s presentation here.
After the business portion of the meeting, attendees got to visit some of the research facilities at USC, including some very impressive prototypes of instrumentation under development for the planned Mars 2020 rover mission. The meeting concluded with a visit to the California Science Center, where the Space Shuttle Endeavour has its retirement home.