F Rosa Rubicondior: Creationism in Crisis - How Eukaryote Life Evolved 800 Million Years Ago

Friday 24 March 2023

Creationism in Crisis - How Eukaryote Life Evolved 800 Million Years Ago

Creationism in Crisis

How Eukaryote Life Evolved 800 Million Years Ago

Carbonate rock samples collected from the North China Craton.
Photo: Christina Franusich for Virginia Tech.
Creationism in Crisis

How Eukaryote Life Evolved 800 Million Years Ago

Virginia Tech Department of Geosciences doctoral student Junyao Kang holds a carbonate rock sample from the North China Craton.
Photo: Christina Franusich for Virginia Tech.

Electron micrograph of part of a eukaryote cell
Electron micrograph of part of a eukaryote cell
Virginia Tech geoscientists shed a light on life’s evolution 800 million years ago | VTx | Virginia Tech

A team of researchers at Virginia Tech has produced evidence of something that would, if they understood its implications, spread despondency throughout the Creationist cults. They have shown that there was a sharp increase by about 50% in the level of biologically available nitrogen in Earth's oceans, 800 million years ago, coincident with the rise of the eukaryotes.

So strongly is this increase associated with the rise of the eukaryotes that the clear implication is that this is what either triggered or at least facilitated this major evolutionary step and that it was the limited availability of biological nitrogen that delayed this change.

The eukaryotes went on to evolve into the multicellular organisms which are the dominant life forms on Earth today.
So, not only is this evidence that there were simple living organisms on Earth 799,990,000 years before Creationists believe the Universe was created, but that the evolution of modern life forms was dependent on environmental change.

As the Virginia Tech news release explains:

Where we sit today, with life as it is on the planet, is the sum total of all the events that happened in the past, and this is a key event where we shift from dominantly prokaryotic ecosystems — cells that are much simpler than the ones in our bodies — to eukaryotes. If that did not happen, we would not be here today.

Associate Professor Benjamin Gill, co-author Associate professor of sedimentary geochemistry
Department of Geosciences
Virginia Tech, Blacksburg, VA, USA
The team's findings, recently published in Science Advances, reveal an increase in biologically available nitrogen during the time that marine eukaryotes — organisms whose cells have a nucleus — became dominate. Complex eukaryotic cells evolved into multicellular organisms and are credited for ushering in a whole new era for life on Earth, including animals, plants, and fungi.

Previous research focused on phosphorus’ role in the rise of eukaryotes, but Junyao Kang, a doctoral student in the Department of Geosciences and lead author of the paper, was curious about the part nitrogen played in this event.

This discovery is unique because nitrogen isotope data are virtually nonexistent from the early Neoproterozoic time period, or between a billion and 800 million years ago.

Junyao Kang, first author
Department of Geosciences
Virginia Tech, Blacksburg, VA, USA.

We had some rough ideas of when eukaryotes became ecologically successful. They had been there for a long time in a low-key status until about 820 million years ago, when they became abundant.

Professor Shuhai Xiao, co-author
Professor of geobiology
Department of Geosciences
Virginia Tech, Blacksburg, VA, USA.
Collaborating with the Nanjing University in Najing, China, Kang has spent two years working to understand what drove the rise of eukaryotes through nitrogen isotope analysis of rock samples from the North China Craton. Home to rocks dating back 3.8 billion years ago, the region was once covered by an ocean.
Kang decided he wanted to learn why. He took the data from the rock samples, entered it into a larger database, and analyzed it across a longer time scale that spanned different geographic locations.

Once we did this kind of integration and put it into a big picture, we saw the rise of nitrates through time, which happened around 800 million years ago.

Junyao Kang
Solid collaboration

A collaborative, international approach was key to connecting this new data with biological events, mostly notably, the rise of eukaryotes.

Gill and Rachel Reid, also a College of Science geochemist and co-author of the paper, provided critical analyses through resources, including the mass spectrometer in the Geoscience Stable Isotope Lab at Virginia Tech. An elemental analyzer coupled to the mass spectrometer allowed the researchers to extract pure nitrogen gas from the samples for analysis.

Gill specializes in reconstructing present and past chemical cycles on our planet. He collaborates with paleontologists to study the record of life preserved in the geological record and examines what potential environmental drivers might have enabled changes in life through history.

Reid, who generally focuses her research on Earth’s more recent events, had a special opportunity to offer her nitrogen isotope expertise to these ancient fossils.

Feifei Zhang, a geochemist at Nanjing University, was the paper's fourth co-author. Zhang provided insights on how much oxygen would have been available in the oceans during the time when nitrate increased in abundance.
Copyright: © 2023 The authors.
Published by American Association for the Advancement of Science.
Open access. (CC BY 4.0)
The teams open access paper in Science Advances gives more detail:

The early Neoproterozoic Era witnessed the initial ecological rise of eukaryotes at ca. 800 Ma. To assess whether nitrate availability played an important role in this evolutionary event, we measured nitrogen isotope compositions (δ15N) of marine carbonates from the early Tonian (ca. 1000 Ma to ca. 800 Ma) Huaibei Group in North China. The data reported here fill a critical gap in the δ15N record and indicate nitrate limitation in early Neoproterozoic oceans. A compilation of Proterozoic sedimentary δ15N data reveals a stepwise increase in δ15N values at ~800 Ma. Box model simulations indicate that this stepwise increase likely represents a ~50% increase in marine nitrate availability. Limited nitrate availability in early Neoproterozoic oceans may have delayed the ecological rise of eukaryotes until ~800 Ma when increased nitrate supply, together with other environmental and ecological factors, may have contributed to the transition from prokaryote-dominant to eukaryote-dominant marine ecosystems.

The sad thing is that Creationists have to shut their minds to this sort of information for fear of having to wonder if they could be wrong and might not be so important that they have a close personal relationship with the creator of the Universe who created it all just for them, after all.

Thank you for sharing!

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