Natural History (13.8 billion years BC – 3.3 million BC)

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Earliest Evidence Yet Reveals Photosynthesis Evolved at Least 1.75 Billion Years Ago
by Michele Starr
January 4, 2024

Introduction:

(Science Alert) Tiny fossils that have spent nearly 2 billion years locked up in chunks of ancient rock are giving us the earliest evidence yet for photosynthesis on Earth.

In the McDermott Formation in the desert of northern Australia, tiny structures called thylakoids have been discovered in what are thought to be fossilized cyanobacteria dating back to 1.75 billion years ago.

These structures are found inside the cells of photosynthetic organisms today that contain the pigment chlorophyll, used to absorb the light for photosynthesis.

This means that the microfossils represent the oldest direct evidence for photosynthesis, giving us a new minimum age for the emergence of thylakoid-bearing cyanobacteria, and a new tool for understanding early Earth ecosystems, and how life emerged on our planet.

"Our study provides direct evidence for the presence of metabolically active cyanobacteria performing oxygenic photosynthesis," writes a team led by paleomicrobiologist Catherine Demoulin of the University of Liège.

Read more here: https://www.sciencealert.com/earliest- ... ears-ago

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New research shows “Juvenile T. rex” fossils are a distinct species of small tyrannosaur

Wednesday 3 January 2024

A new analysis of fossils believed to be juveniles of T. rex now shows they were adults of a small tyrannosaur, with narrower jaws, longer legs, and bigger arms than T. rex. The species, Nanotyrannus lancensis, was first named decades ago but later reinterpreted as a young T. rex.

The first skull of Nanotyrannus was found in Montana in 1942, but for decades, paleontologists have gone back and forth on whether it was a separate species, or simply a juvenile of the much larger T. rex.

Dr Nick Longrich, from the Milner Centre for Evolution in the Department of Life Sciences at the University of Bath (UK), and Dr Evan Saitta, from the University of Chicago (USA) re-analysed the fossils, looking at growth rings, the anatomy of Nanotyrannus, and a previously unrecognized fossil of a young T. rex.

Measuring the growth rings in Nanotyrannus bones, they showed that they became more closely packed towards the outside of the bone - its growth was slowing. It suggests these animals were nearly full size; not fast-growing juveniles.

Modelling the growth of the fossils showed the animals would have reached a maximum of around 900-1500 kilograms and five metres - about 15 per cent of the size of the giant T. rex, which grew to 8,000 kilograms and nine metres or more.

https://www.bath.ac.uk/announcements/ne ... rannosaur/



Credit Raul Martin

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'Giant' predatory worm half a billion years old unearthed in Greenland
By Bronwyn Thompson
January 04, 2024
https://newatlas.com/biology/giant-pred ... greenland/

Scientists have uncovered fossils detailing a new huge predatory worm species thought to have hunted in the Earth’s water column more than 518 million years ago.

Researchers from the University of Bristol's Schools of Earth Sciences and Biological Sciences believe this worm – named Timorebestia, or ‘terror beast’ in Latin – was one of the planet’s earliest carnivorous swimming animals and part of a diverse “dynasty” of predators that until now was unknown to scientists.

"We have previously known that primitive arthropods were the dominant predators during the Cambrian, such as the bizarre-looking anomalocaridids," said Jakob Vinther, a senior author on the study. "However, Timorebestia is a distant, but close, relative of living arrow worms, or chaetognaths. These are much smaller ocean predators today that feed on tiny zooplankton."

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Study Uncovers Potential Origins of Life in Ancient Hot Springs
January 12, 2024

Introduction:

(Eurekalert) Newcastle University research turns to ancient hot springs to explore the origins of life on Earth.

The research team, funded by the UK’s Natural Environmental Research Council, investigated how the emergence of the first living systems from inert geological materials happened on the Earth, more than 3.5 billion years ago. Scientists at Newcastle University found that by mixing hydrogen, bicarbonate, and iron-rich magnetite under conditions mimicking relatively mild hydrothermal vent results in the formation of a spectrum of organic molecules, most notably including fatty acids stretching up to 18 carbon atoms in length.

Published in the journal Communications Earth & Environment, their findings potentially reveal how some key molecules needed to produce life are made from inorganic chemicals, which is essential to understanding a key step in how life formed on the Earth billions of years ago. Their results may provide a plausible genesis of the organic molecules that form ancient cell membranes, that were perhaps selectively chosen by early biochemical processes on primordial Earth.

Fatty acids in the early stages of life

Fatty acids are long organic molecules that have regions that both attract and repel water that will automatically form cell-like compartments in water naturally and it is these types of molecules that could have made the first cell membranes. Yet, despite their importance, it was uncertain where these fatty acids came from in the early stages of life. One idea is that they might have formed in the hydrothermal vents where hot water, mixed with hydrogen-rich fluids coming from underwater vents mixed with seawater containing CO2.

The group replicated crucial aspects of the chemical environment found in early Earth's oceans and the mixing of the hot alkaline water from around certain types of hydrothermal vents in their laboratory. They found that when hot hydrogen-rich fluids were mixed with carbon dioxide-rich water in the presence of iron-based minerals that were present on the early Earth it created the types of molecules needed to form primitive cell membranes.

Read more of the Eurealert article here: https://www.eurekalert.org/news-releases/1031146

For a technical presentation of study results as presented in Nature: https://www.nature.com/articles/s43247-023-01196-4.pdf

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Megalodons Were Long and Skinny, Not Short and Beefy: Study
The great white may be a poor analog for megalodon.
By Ryan Whitwam January 24, 2024
https://www.extremetech.com/science/meg ... eefy-study

As anyone who grew up on Shark Week can tell you, the megalodon was the biggest, baddest shark to swim the oceans of ancient Earth. However, the image you have in your head of megalodon—a larger and even more toothy version of the modern great white—may not be accurate. A new study claims that in life, megalodon had a totally different body type with a slender frame and even greater total length.

Shark teeth are among the most common marine fossils because these creatures are constantly losing and replacing their chompers. In the case of megalodon, the teeth were the size of butcher knives, which has guaranteed its notoriety millions of years after these super sharks disappeared from Earth's oceans—possibly because of a supernova. Aquariums and museums sometimes display models of reconstructed megalodon jaws, inviting visitors to stand inside them for a photo op.

Most of what we know of megalodon is based on the teeth and jaws—only a few segments of backbone and scales have been discovered, and the rest of a shark's body is cartilage that doesn't fossilize. In the 1990s, scientists used the vertebrae to estimate the size of the extinct shark. In great whites, there's an established ratio between the width of vertebrae and the animal's total length. Based on that, scientists have believed megalodons were around 30 feet long.

The new study, led by Kenshu Shimada at DePaul University and Phillip Sternes from the University of California, reevaluates those fossils and arrives at a different conclusion. This assessment is based on the diameter of the vertebral column. The team claims it's too narrow to support a large shark with the proportions of a great white. Such an animal would be at risk of spinal injuries as it blasted through the water at high speed. Instead, the study suggests a more narrow and elongated body shape.

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Inner ear of 6-million-year-old ape fossil reveals clues about the evolution of human movement
https://phys.org/news/2024-01-ear-milli ... ossil.html
by New York University

Humans and our closest relatives, living apes, display a remarkable diversity of types of locomotion—from walking upright on two legs to climbing in trees and walking using all four limbs.

While scientists have long been intrigued by the question of how humans' bipedal stance and movement evolved from a quadrupedal ancestor, neither past studies nor fossil records have permitted the reconstruction of a clear and definitive history of the early evolutionary stages that led to human bipedalism

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Fossilized 350 Million-Year-Old Plant Is Like Nothing You’ve Ever Seen Before
by Eleanor Higgs
February 2, 2024

Introduction:

(IFL Science) While fossilized plants turn up fairly often in the fossil record, they are usually preserved as a trunk or the odd leaf, giving little idea of what the whole tree might have looked like. Newly discovered fossilized trees from New Brunswick, Canada however have enough in the record to reveal that they had a very surprising appearance that has never been seen before.

“The way in which this tree produced hugely long leaves around its spindly trunk, and the sheer number over a short length of trunk, is startling,” said Robert Gastaldo of Colby College in Waterville, Maine in a statement.

Ferns and palm trees are seen in the fossil record – and while this new plant resembles a palm, Sanfordiacaulisis is thought to be 350 million years old, which outdates the existence of palms known in the fossil record by 300 million years. Palm tree leaves usually cluster at the top in small numbers, but the new fossil tree is thought to have had over 250 large leaves not just at the top of the plant but growing around the trunk too.

“Sanfordiacaulis preserves more than 250 leaves around its trunk, with each partially preserved leaf extending 1.75 meters from it,” Gastaldo said.

The tree had a trunk of around 16 centimeters (6.2 inches) in diameter, with leaves that started growing around the trunk in a spiral branching pattern with very dense growth, resulting in a voluminous crown at the top of the tree.

Read more here (including illustations): https://www.iflscience.com/fossilized- ... ore-72769

[Powers]

^^^ That's one ugly reconstruction.