EGU Blogs

Triassic

Molecular clocks and the End-Permian mass extinction

September 11, 2015

Earth’s history is punctuated by extreme events known as mass extinctions. The End-Permian extinction, 252 million years ago, is believed to be the biggest, killing 90 % or more of all species – no wonder it is also called “The Great Dying”. The big question out there is to understand what caused it, but it is a challenge to get the complete picture of an event so long ago in prehistory. We know that the Siberian Traps (the enormous field of volcanic rock that lies in Siberia) were formed around that time and that volcanic activity was a likely trigger for this mass extinction. But what actually happened? And why did so many species, including many groups of insects, disappear?

Last year, an article appeared that brought forward a new hypothesis. From evidence in rock cores, Daniel Rothman and co-authors [1,2] concluded that around the end of the Permian, a lot of organic carbon that was formerly trapped in the sediments was converted into CO2. This change happened so fast that its release was exponential.

When genes are passed on from microbe A to microbe B, both undergo a certain number of mutations per period of time.

When genes are passed on from microbe A to microbe B, both undergo a certain number of mutations per period of time.

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It’s kind of like a turtle-fish-dolphin…

January 26, 2015

Close your eyes. Go back in time 250 million years, and the world would seems as strange to you as a different planet. On land, there was a whole host of bizarre and now extinct animals: strange, crocodile-like things, and the precursors of dinosaurs; weird mammal-like beasts, that looked like the lost offspring of a hippo and a monitor lizard.

In the seas, marine reptiles dominated. A whole range of unusual animals lived, such as the long-necked plesiosaurs, popularised with reference to the mythical Loch Ness monster. Alongside these were the equally unusual ichthyosaurs. At first glance, a typical one might look like to you much like a dolphin.

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What do we know about the origin of flowering plants?

October 15, 2013

bioThis is a guest post by Dan Peppe.  He is an Assistant Professor in the Geology Department at Baylor University.  His research interests are focused on reconstructing ancient climates and ecosystems in North America and East Africa and on developing new and improved palaeoclimate and palaeoecological proxies using methods in paleobotany, sedimentary geology, and paleomagnetism.  More information about Dan and his research can be found on his website: www.danielpeppe.com.  He also tweets about his research and other interests on his Twitter account (@danpeppe). 

Over the last couple of weeks several blogs and news outlet have reported that a new study published in Frontiers in Plant Science (Hochuli and Feist-Burkhardt, 2013) shows that new fossil pollen push back the origin of flowering plants (angiosperms) by 100 million years to the early Triassic (e.g., LiveScience, BBC, ScienceDaily). The headlines and articles lead a reader to assume that there was new evidence showing that angiosperms were present in the Triassic (252-201 million years ago, Ma).  However, the new study actually suggests something quite different that adds to a growing body of evidence pertaining to a larger narrative about the evolution of plants and the evolution of angiosperms.

Fossil charcoalified floras from a Late Cretaceous (Santonian, 86 – 83 Ma) in central Georgia showing amazing 3D preservation and anatomical detail. Images were taken using a scanning electron microscope and are considerably magnified (A magnified X50, B X100, C X20). Flower images are from Figure 4 of Crane et al. (2004).

Fossil charcoalified floras from a Late Cretaceous (Santonian, 86 – 83 Ma) in central Georgia showing amazing 3D preservation and anatomical detail. Images were taken using a scanning electron microscope and are considerably magnified (A magnified X50, B X100, C X20). Flower images are from Figure 4 of Crane et al. (2004).

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The early evolution of dinosaurs

April 22, 2013

Dinosaurs. What springs to mind when they’re mentioned? Colossal, towering sauropods? Packs of feisty feathered fiends? Or huge herds of hadrosaurs, chomping their way across the plains of long-lost worlds? Most, including myself, will automatically default to any one of these images when dinosaurs come up in conversation (what, you mean it’s not that frequent for normal people?) But we often neglect to think the earliest dinosaurs, spectacular organisms that gave birth to the most successful, and on-going, terrestrial vertebrate radiation of all time.

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