World´s first animals, Greenland discovery

This 21 July 2020 video is called The Cambrian Explosion and the evolutionary origin of animals with Professor Paul Smith.

From Uppsala University in Sweden:

Half-a-billion year old microfossils may yield new knowledge of animal origins

November 9, 2020

When and how did the first animals appear? Science has long sought an answer. Uppsala University researchers and colleagues in Denmark have now jointly found, in Greenland, embryo-like microfossils up to 570 million years old, revealing that organisms of this type were dispersed throughout the world. The study is published in Communications Biology.

“We believe this discovery of ours improves our scope for understanding the period in Earth’s history when animals first appeared — and is likely to prompt many interesting discussions,” says Sebastian Willman, the study’s first author and a palaeontologist at Uppsala University.

The existence of animals on Earth around 540 million years ago (mya) is well substantiated. This was when the event in evolution known as the “Cambrian Explosion” took place. Fossils from a huge number of creatures from the Cambrian period, many of them shelled, exist. The first animals must have evolved earlier still; but there are divergent views in the research community on whether the extant fossils dating back to the Precambrian Era are genuinely classifiable as animals.

The new finds from the Portfjeld Formation in the north of Greenland may help to enhance understanding of the origin of animals. In rocks that are 570-560 mya, scientists from Uppsala University, the University of Copenhagen and the Geological Survey of Denmark and Greenland have found microfossils of what might be eggs and animal embryos. These are so well preserved that individual cells, and even intracellular structures, can be studied. The organisms concerned lived in the shallow coastal seas around Greenland during the Ediacaran period, 635-541 mya. The immense variability of microfossils has convinced the researchers that the complexity of life in that period must have been greater than has hitherto been known.

Similar finds were uncovered in southern China’s Doushantuo Formation, which is nearly 600 million years old, over three decades ago. Since then, researchers have been discussing what kinds of life form the microfossils represented, and some think they are eggs and embryos from primeval animals. The Greenland fossils are somewhat younger than, but largely identical to, those from China.

The new discovery means that the researchers can also say that these organisms were spread throughout the world. When they were alive, most continents were spaced out south of the Equator. Greenland lay where the expanse of the Southern Ocean (surrounding Antarctica) is now, and China was roughly at the same latitude as present-day Florida.

“The vast bedrock, essentially unexplored to date, of the north of Greenland offers opportunities to understand the evolution of the first multicellular organisms, which in turn developed into the first animals that, in their turn, led to us,” Sebastian Willman says.

Ancient ice age and multicellular animals

This 2019 video says about itself:

How Volcanoes Froze the Earth (Twice)

Over 600 million years ago, sheets of ice coated our planet on both land and sea. How did this happen? And most importantly for us, why did the planet eventually thaw again? The evidence for Snowball Earth is written on every continent today.

From the University of Rochester in the USA:

Clues to a dramatic chapter of Earth’s geological history

June 15, 2020

Summary: How could the planet be covered entirely in ice — a state known as ‘Snowball Earth‘– and still give rise to multicellular life? The transition to such icy periods may not have been as abrupt as previously thought, new research shows.

Imagine Earth completely covered in ice. While it’s hard to picture all of today’s oceans and land masses obscured with glaciers, such an ice-covered version of the planet was not so far-fetched millions of years ago.

Lasting from approximately 1,000 to 540 million years ago, the dramatic chapter is an important part of Earth’s 4.5-billion-year history. Known as the Neoproterozoic Era, the period of severe glaciation was a time when multicellular organisms were beginning to diversify and spread across the planet.

Many researchers posit that ice may have covered every surface of the planet, stretching from the poles all the way to the hot tropics of the equator — a hypothesis known as “Snowball Earth.”

How was it possible there was global ice — even in the warmest areas of Earth?

Researchers from the University of Rochester are shedding new light on that question. By analyzing mineral data left by glaciers before the onset of the Neoproterozoic Era, Scott MacLennan, a postdoctoral research associate in the lab of Mauricio Ibanez-Mejia, an assistant professor in the Department of Earth and Environmental Sciences, present the first geological evidence that Earth may have had a cool climate before Snowball Earth.

The study, published in Science Advances, provides important information about a period of the planet’s history that paved the way for the development of complex life on Earth.

“This is a fascinating period, as these dramatic environmental changes happened right as the first true animals were beginning to appear and evolve on Earth,” Ibanez-Mejia says.


A critical aspect of understanding a period of planetwide glaciation is determining what the climate was like before Snowball Earth. Computer models indicate that a cool global climate was necessary in order to initiate a Snowball Earth state, but such a state has not been confirmed by geological evidence. Instead, geological evidence has previously suggested that Earth had a warm and ice-free climate immediately prior to the Neoproterozoic glaciation.

While scientists don’t know the exact mechanisms that may have caused Snowball Earth, they suspect that whatever they were, the mechanisms involved a massive decrease in atmospheric carbon dioxide concentrations. There are several scenarios in which the atmospheric carbon dioxide may have decreased. They include an increase in biomass in the oceans, which may have taken carbon dioxide out of the atmosphere and turned it into organic matter, or an increase in the weathering of the continental crust, which also takes up carbon dioxide.

In order to determine whether these scenarios are feasible, however, it’s critical to know more about Earth’s climate before the massive glaciation events started.

“If the Earth was very hot, it would mean the ocean was storing a lot of heat, which would take a lot of time to get rid of in order to create a Snowball Earth,” MacLennan says.


Scientists can determine Earth’s climate at points in time by studying rocks that were deposited at different times throughout Earth’s history. MacLennan and his colleagues used zircon dating methods to very precisely date glacial rocks found in modern-day Virginia. Paleomagnetic data, which allows researchers to determine where the continents were located thousands and even millions of years ago, have established that Virginia was located in the middle of a supercontinent within the tropics while the glacial rocks were being deposited. The supercontinent later broke up into smaller parts.

The researchers discovered that the glacial rocks were actually deposited 30 million years before the first Snowball Earth. The observation was surprising because they had expected the glacial rocks to be related to the Snowball Earth event. Instead, the discovery indicates that there were glaciers in the tropics near the equator — albeit at potentially high altitudes — even before Snowball Earth.

“The planet always gets colder away from the tropics and toward the poles because Earth receives most of its incoming sunlight at the equator,” MacLennan says. “If there are glaciers in the tropics, the rest of the planet must have also been very cold. This means that our previous vision of a hot, humid world before the Snowball Earth is probably incorrect.”

The potential trigger mechanism for the massive global cooling therefore may not have been as extreme as some researchers believe; the planet didn’t immediately turn from a warm state to a frozen state but instead appears to have experienced a more gradual cool-off into a Snowball Earth state.


This research raises interesting questions about what Earth was really like 800 to 700 million years ago, before Snowball Earth events, during a time when interesting biological innovations were taking place as multicellular organisms were beginning to diversify.

“There have been a lot of questions about how multi- and single-cellular life forms would survive the Snowball Earths, especially if there was a rapid transition from a hot greenhouse world,” MacLennan says. “Our estimates for pre-Snowball climate imply the planet was probably colder than the modern world, which means there may have been ample cold environments at high latitude and altitude where organisms could have adapted to these cold conditions.”

Dickinsonia, ancient Ediacaran animals

This 29 May 2020 video says about itself:

How We Identified One of Earth’s Earliest Animals

Scientists had no idea what type of organisms the life forms of the Ediacaran were—lichen, colonies of bacteria, fungi or something else. It turns out, the key to solving the puzzle of Precambrian life was a tiny bit of fossilized fat.

Oldest of all animals discovered in Australia

Ikaria wariootia reconstruction (Sohail Wasif/UCR)

From the University of California – Riverside in the USA:

Ancestor of all animals identified in Australian fossils

A wormlike creature that lived more than 555 million years ago is the earliest bilaterian

March 23, 2020

A team led by UC Riverside geologists has discovered the first ancestor on the family tree that contains most familiar animals today, including humans.

The tiny, wormlike creature, named Ikaria wariootia, is the earliest bilaterian, or organism with a front and back, two symmetrical sides, and openings at either end connected by a gut. The paper is published today in Proceedings of the National Academy of Sciences.

The earliest multicellular organisms, such as sponges and algal mats, had variable shapes. Collectively known as the Ediacaran Biota, this group contains the oldest fossils of complex, multicellular organisms. However, most of these are not directly related to animals around today, including lily pad-shaped creatures known as Dickinsonia that lack basic features of most animals, such as a mouth or gut.

The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organize their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organized around this same basic bilaterian body plan.

Evolutionary biologists studying the genetics of modern animals predicted the oldest ancestor of all bilaterians would have been simple and small, with rudimentary sensory organs. Preserving and identifying the fossilized remains of such an animal was thought to be difficult, if not impossible.

For 15 years, scientists agreed that fossilized burrows found in 555 million-year-old Ediacaran Period deposits in Nilpena, South Australia, were made by bilaterians. But there was no sign of the creature that made the burrows, leaving scientists with nothing but speculation.

Scott Evans, a recent doctoral graduate from UC Riverside; and Mary Droser, a professor of geology, noticed miniscule, oval impressions near some of these burrows. With funding from a NASA exobiology grant, they used a three-dimensional laser scanner that revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. The animal ranged between 2-7 millimeters long and about 1-2.5 millimeters wide, with the largest the size and shape of a grain of rice — just the right size to have made the burrows.

“We thought these animals should have existed during this interval, but always understood they would be difficult to recognize,” Evans said. “Once we had the 3D scans, we knew that we had made an important discovery.”

The researchers, who include Ian Hughes of UC San Diego and James Gehling of the South Australia Museum, describe Ikaria wariootia, named to acknowledge the original custodians of the land. The genus name comes from Ikara, which means “meeting place” in the Adnyamathanha language. It’s the Adnyamathanha name for a grouping of mountains known in English as Wilpena Pound. The species name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station.

“Burrows of Ikaria occur lower than anything else. It’s the oldest fossil we get with this type of complexity,” Droser said. “Dickinsonia and other big things were probably evolutionary dead ends. We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for.”

In spite of its relatively simple shape, Ikaria was complex compared to other fossils from this period. It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities. The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.

The burrows also preserve crosswise, “V”-shaped ridges, suggesting Ikaria moved by contracting muscles across its body like a worm, known as peristaltic locomotion. Evidence of sediment displacement in the burrows and signs the organism fed on buried organic matter reveal Ikaria probably had a mouth, anus, and gut.

“This is what evolutionary biologists predicted,” Droser said. “It’s really exciting that what we have found lines up so neatly with their prediction.”

Ancient rangeomorph animal networks, new research

This 7 March 2020 video says about itself:

Rangeomorphs had no mouths, guts, arms, legs or reproductive organs, but an ancient “network” of strings may have helped them dominate the ocean floor anyway.

Some of the earliest animals on Earth may have used social networks to chat with each other, review food — and yes — maybe even sext.

In a study published Thursday (March 5) in the journal Current Biology, researchers looked at hundreds of rangeomorphs — bizarre, fern-like animals that lived in large colonies on the bottom of the ocean from about 571 million to 541 million years ago — fossilized along the coast of Newfoundland, Canada. To the team’s surprise, many of the fossil specimens appeared to be connected to each other by long, string-like filaments never seen among animals this old. Individual filaments spanned anywhere from a few inches to 13 feet in length and connected rangeomorphs from seven different species, forming a primitive “social network” of deep-sea dwellers.

These organisms seem to have been able to quickly colonize the seafloor, and we often see one dominant species on these fossil beds. These filaments may explain how they were able to do that.

Rangeomorphs are thought to be some of the earliest non-microscopic animals on Earth, spreading prolifically 635 million to 541 million years ago, despite having no noticeable mouths, guts, reproductive organs or means of moving around.

Scientists think the creatures dug into the mud on the ocean floor, passively sucking nutrients out of the water using symmetrical, leaf-like branches. Their methods worked well, apparently, as rangeomorph colonies dominated huge plots of the seafloor for 30 million years. Different species ranged from less than 1 inch to 6.5 feet in length, and some may have physically changed shape to better capitalize on the nutrients available around them.

Because rangeomorphs never really moved around, the fossil record includes entire colonies of the creatures preserved as they actually lived. When professor at the University of Cambridge’s Department of Earth Sciences Alexander Liu and his colleagues found fossilized filaments connecting rangeomorphs at 38 different dig sites, it became clear that this sinewy “network” played an important role in connecting individual colony members.

Further study of rangeomorph fossils is required to unravel the mystery of these filaments; alas, it seems this social network is password-protected.

See here. And here.

Billion-year-old seaweed fossils, ancestors of land plants?

Proteroclasus antiquus, microscope photo, image credit Shuhai Xiao, Qing Tang / Virginia Tech

From Virginia Tech in the USA:

One billion-year-old green seaweed fossils identified, relative of modern land plants

February 24, 2020

Virginia Tech paleontologists have made a remarkable discovery in China: 1 billion-year-old micro-fossils of green seaweeds that could be related to the ancestor of the earliest land plants and trees that first developed 450 million years ago.

The micro-fossil seaweeds — a form of algae known as Proterocladus antiquus — are barely visible to the naked eyed at 2 millimeters in length, or roughly the size of a typical flea. Professor Shuhai Xiao said the fossils are the oldest green seaweeds ever found. They were imprinted in rock taken from an area of dry land — formerly ocean — near the city of Dalian in the Liaoning Province of northern China. Previously, the earliest convincing fossil record of green seaweeds were found in rock dated at roughly 800 million years old.

The findings — led by Xiao and Qing Tang, a post-doctoral researcher, both in the Department of Geosciences, part of the Virginia Tech College of Science — are featured in the latest issue of Nature Ecology & Evolution.

“These new fossils suggest that green seaweeds were important players in the ocean long before their land-plant descendants moved and took control of dry land,” Xiao said.

“The entire biosphere is largely dependent on plants and algae for food and oxygen, yet land plants did not evolve until about 450 million years ago,” Xiao said. “Our study shows that green seaweeds evolved no later than 1 billion years ago, pushing back the record of green seaweeds by about 200 million years. What kind of seaweeds supplied food to the marine ecosystem?”

Shuhai said the current hypothesis is that land plants — the trees, grasses, food crops, bushes, even kudzu — evolved from green seaweeds, which were aquatic plants. Through geological time — millions upon millions of years — they moved out of the water and became adapted to and prospered on dry land, their new natural environment. “These fossils are related to the ancestors of all the modern land plants we see today.”

However, Xiao added the caveat that not all geobiologists are on the same page — that debate on the origins of green plants remains debated. “Not everyone agrees with us; some scientists think that green plants started in rivers and lakes, and then conquered the ocean and land later,” added Xiao, a member of the Virginia Tech Global Change Center.

There are three main types of seaweed: brown (Phaeophyceae), green (Chlorophyta), and red (Rhodophyta), and thousands of species of each kind. Fossils of red seaweed, which are now common on ocean floors, have been dated as far back as 1.047 billion years old.

“There are some modern green seaweeds that look very similar to the fossils that we found,” Xiao said. “A group of modern green seaweeds, known as siphonocladaleans, are particularly similar in shape and size to the fossils we found.”

Photosynthetic plants are, of course, vital to the ecological balance of the planet because they produce organic carbon and oxygen through photosynthesis, and they provide food and the basis of shelter for untold numbers of mammals, fish, and more. Yet, going back 2 billion years, Earth had no green plants at all in oceans, Xiao said.

It was Tang who discovered the micro-fossils of the seaweeds using an electronic microscope at Virginia Tech’s campus and brought it to Xiao’s attention. To more easily see the fossils, mineral oil was dripped onto the fossil to create a strong contrast.

“These seaweeds display multiple branches, upright growths, and specialized cells known as akinetes that are very common in this type of fossil,” he said. “Taken together, these features strongly suggest that the fossil is a green seaweed with complex multicellularity that is circa 1 billion years old. These likely represent the earliest fossil of green seaweeds. In short, our study tells us that the ubiquitous green plants we see today can be traced back to at least 1 billion years.”

According to Xiao and Tang, the tiny seaweeds once lived in a shallow ocean, died, and then became “cooked” beneath a thick pile of sediment, preserving the organic shapes of the seaweeds as fossils. Many millions of years later, the sediment was then lifted up out of the ocean and became the dry land where the fossils were retrieved by Xiao and his team, which included scientists from Nanjing Institute of Geology and Paleontology in China.

See also here.

Precambrian worm-like fossil discovery

This March 2018 video says about itself:

Fossils found around the world suggest that multi-cellular life was not only present before the Cambrian Explosion, it was much more elaborate and diverse than anyone thought. This is the story of the sudden burst of diversity that marked the dawn of truly complex life on our planet.

A three-dimensional image of a 550 million-year-old fossilized tube (left, in red) with internal digestive tract (gold, left and right)

From the University of Missouri-Columbia in the USA:

Scientists find oldest-known fossilized digestive tract — 550 million years

January 10, 2020

A 550-million-year-old fossilized digestive tract found in the Nevada desert could be a key find in understanding the early history of animals on Earth.

Over a half-billion years ago, life on Earth was composed of simple ocean organisms unlike anything living in today’s oceans. Then, beginning about 540 million years ago, animal structures changed dramatically.

During this time, ancestors of many animal groups we know today appeared, such as primitive crustaceans and worms, yet for years scientists did not know how these two seemingly unrelated communities of animals were connected, until now. An analysis of tubular fossils by scientists led by Jim Schiffbauer at the University of Missouri provides evidence of a 550 million-year-old digestive tract — one of the oldest known examples of fossilized internal anatomical structures — and reveals what scientists believe is a possible answer to the question of how these animals are connected.

The study was published in Nature Communications, a journal of Nature.

“Not only are these structures the oldest guts yet discovered, but they also help to resolve the long-debated evolutionary positioning of this important fossil group,” said Schiffbauer, an associate professor of geological sciences in the MU College of Arts and Science and director of the X-ray Microanalysis Core facility. “These fossils fit within a very recognizable group of organisms — the cloudinids — that scientists use to identify the last 10 to 15 million years of the Ediacaran Period, or the period of time just before the Cambrian Explosion. We can now say that their anatomical structure appears much more worm-like than coral-like.”

The Cambrian Explosion is widely considered by scientists to be the point in history of life on Earth when the ancestors of many animal groups we know today emerged.

In the study, the scientists used MU’s X-ray Microanalysis Core facility to take a unique analytical approach for geological science — micro-CT imaging — that created a digital 3D image of the fossil. This technique allowed the scientists to view what was inside the fossil structure.

“With CT imaging, we can quickly assess key internal features and then analyze the entire fossil without potentially damaging it,” said co-author Tara Selly, a research assistant professor in the Department of Geological Sciences and assistant director of the X-ray Microanalysis Core facility.

The study, “Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period,” was published in Nature Communications. Other authors include Sarah Jacquet from MU; Rachel Merz from Swarthmore College; Michael Strange from the University of Nevada, Las Vegas; Yaoping Cai from Northwest University in Xi’an, China; and Lyle Nelson and Emmy Smith from Johns Hopkins University.

Funding was provided by grants from the NSF Sedimentary Geology and Paleobiology Program (CAREER 1652351) and Instrumentation and Facilities Program (1636643). The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding agencies.

Origins of animals, plants, fungi, new research

This 18 June 2018 video says about itself:

Phylogenomic-wide studies of evolutionarily conserved structures of protein domains suggest Archaea is the first domain of life to diversify from a stem line of descent and co-evolve with ancestors of Bacteria and Eukarya. The proposed co-evolutionary scenario by J. T. Staley and G. Caetano-Anollés challenges popular cell fusion and two-domain of life scenarios derived from sequence analysis.

For more, read the full article here.

From Molecular Biology and Evolution (Oxford University Press):

Scientists identify rare evolutionary intermediates to understand the origin of eukaryotes

September 11, 2019

Summary: A new study provides a key insight into a milestone event in the early evolution of life on Earth — the origin of the cell nucleus and complex cells. Scientists peered deep inside current living cells, known as Archaea – the organisms that are believed to most closely resemble the ancient intermediates between bacteria and the more complex cells that we now know as eukaryotic cells.

A new study by Yale scientists provides a key insight into a milestone event in the early evolution of life on Earth — the origin of the cell nucleus and complex cells called eukaryotes.

While simple prokaryotic bacteria formed within the first billion years of the Earth, the origin of eurkaryotes, the first cells with nuclei, took much longer. Dating back to between 1.7 and 2.7 billion years ago, an ancient prokaryote was first transformed with a compartment, the nucleus, designed to keep their DNA material more protected from the environment (such as harmful UV damage). From this ancient event, relatively simple organisms, such as bacteria were transformed into more sophisticated ones that ultimately gave rise to all modern animals, plants and fungi.

The details of this key event have remained elusive for many years because not a single transitional fossil has been found to date.

Now, in a study led by Dr. Sergey Melnikov, from the Dieter Söll Laboratory in the Department of Molecular Biophysics and Biochemistry at Yale University, has finally found these missing fossils. To do so, they relied not on unearthing clay or rocks but peering deep inside current living cells, known as Archaea — the organisms that are believed to most closely resemble the ancient intermediates between bacteria and the more complex cells that we now know as eukaryotic cells.

These transitional forms are nothing like the traditional fossils we think of, such as dinosaur bones deposited in the ground or insects trapped in amber. Known as ribosomal proteins, these particular transitional forms are about 100-million times smaller than our bodies. Melnikov and his colleagues discovered that ribosomal proteins can be used as living “molecular fossils”, whose ancient origin and structure may hold the key to understanding the origin of the cell nucleus.

“Simple lifeforms, such as bacteria, are analogous to a studio apartment: they have a single interior space which is not subdivided into separate rooms or compartments. By contrast, more complex organisms, such as fungi, animals, and plants, are made up of cells that are separated into multiple compartments,” explained Melnikov. “These microscopic compartments are connected to one another via ‘doors’ and ‘gates’. To pass through these doors and gates, the molecules that inhabit living cells must carry special ID badges, some of which are called nuclear localization signals, or NLSs.”

Seeking to better understand when NLS-motifs might have emerged in ribosomal proteins, the Yale team assessed their conservation among ribosomal proteins from the three domains of life.

To date, NLS-motifs have been characterized in ten ribosomal proteins from several eukaryotic species. They compared all of the NLS-motifs found in eukaryotic ribosomal proteins (from 482 species) and tried to find a match in bacteria (2,951 species) and Archaea (402 species).

Suprisingly, they found four proteins — uL3, uL15, uL18, and uS12 — to have NLS-type motifs not only in the Eukarya but also in the Archaea. “Contrary to our expectations, we found that NLS-type motifs are conserved across all the archaeal branches, including the most ancient superphylum, called DPANN,” said Melnikov.

But since Archaea don’t have nuclei, the logical question which then arose was, why do they have these IDs? And what was the original biological function of these IDs in non-compartmentalized cells?”

“If you think about an equivalent to our discovery in the macroscopic world, it is similar to discoveries made during the last century of bird-like dinosaurs such as Caudipteryx zoui,” said Melnikov. “These ancient flightless birds have illustrated that it took multiple millions of years for dinosaurs to develop wings. Yet, strikingly, for the first few million years their wings were not good enough to support flight.”

Similarly, the study by Melnikov and colleagues suggests that, even though NLSs may not initially have emerged to allow cellular molecules to pass through microscopic doors and gates between cellular compartments, they could have emerged to fulfill a similar biological function — to help molecules get to their proper biological partners.

As Melnikov explains: “Our analysis shows that in complex cells the very same IDs that allow proteins to pass through the microscopic gates are also used to recognize biological partners of these proteins. In other words, in complex cells, the IDs fulfill two conceptually similar biological functions. In the Archaea, however, these IDs play just one of these functions — these IDs, or NLSs, help proteins to recognize their biological partners and distinguish them from the thousands of other molecules that float in a cell.”

But what led to the evolution of these IDs among cellular proteins in the first place?

As Melnikov explains, “When life first emerged on the face of our planet, the earliest life forms were likely made of a very limited number of molecules. Therefore, it was relatively easy for these molecules to find one specific partner among all the other molecules in a living cell. However, as cells grew in size and complexity, it is possible, even probable, that the old rules of specific interactions between cellular molecules had to be redefined, and this is how the IDs were introduced into the structure of cellular proteins — to help these proteins identify their molecular partners more easily in the complex environment of a complex cell. Coming back to the analogy with bird-like dinosaurs, our study illustrates the remarkable similarity between how evolution happens in the macroscopic world and how evolution happens in the world that Darwin never saw — the microscopic world of invisible molecules that inhabit living cells.”

There are over 500,000 plant species in the world today. They all evolved from a common ancestor. How this leap in biodiversity happened is still unclear. In the upcoming issue of Nature, an international team of researchers, including scientists from Martin Luther University Halle-Wittenberg, presents the results of a unique project on the evolution of plants. Using genetic data from 1,147 species the team created the most comprehensive evolutionary tree for green plants to date: here.

Precambrian animal fossils, trails discovery

This 2014 David Attenborough video says about itself:

The first animal on the planet – Dickinsonia

The fossils of the first animal can be found in the Ediacara Hills in South Australia. This animal is called Dickinsonia. It was a cushion-like creature that lay on the seafloor. Its size ranged from a penny to a bath mat. It crept around very slowly to look for food.

This 4 September 2019 video says about itself:

A 550 million-year-old worm could shed light into how life on earth started moving. The creature, discovered in southern China, was among the earliest animals capable of movement – a “monumental event” in evolution, the international team that found him noted. The primitive bug was dug up on the banks of the Yangtze River in western Hubei Province.

It was a millipede-like creature a quarter-inch to an inch wide and up to four inches long. The creepy crawly moved by dragging its body across the muddy ocean floor, resting occasionally along the way.

The animal was an elongated narrow creature with 50 or so body segments, a left and right side, a back and belly, with a head and a tail. Only a few creatures from this time – known geologically as the late Ediacaran – have been shown to have roamed about.

Evidence of their movement comes from trackways and burrows rather than actual remains, making the new species particularly historic. The remarkable fossil even includes the worm’s final trail which the international team describe as a “death march”. The animal has been called Yilingia spiciformis, which means spiky Yiling bug after a nearby city.

From Virginia Tech university in the USA:

Ancient animal species: Fossils dating back 550 million years among first animal trails

September 4, 2019

Summary: A geoscientist calls the unearthed fossils, including the bodies and trails left by an ancient animal species, the most convincing sign of ancient animal mobility, dating back about 550 million years.

In a remarkable evolutionary discovery, a team of scientists co-led by a Virginia Tech geoscientist has discovered what could be among the first trails made by animals on the surface of the Earth roughly a half-billion years ago.

Shuhai Xiao, a professor of geosciences with the Virginia Tech College of Science, calls the unearthed fossils, including the bodies and trails left by an ancient animal species, the most convincing sign of ancient animal mobility, dating back about 550 million years. Named Yilingia spiciformis — that translates to spiky Yiling bug, Yiling being the Chinese city near the discovery site — the animal was found in multiple layers of rock by Xiao and Zhe Chen, Chuanming Zhou, and Xunlai Yuan from the Chinese Academy of Sciences’ Nanjing Institute of Geology and Palaeontology.

The findings are published in the latest issue of Nature. The trials are from the same rock unit and are roughly the same age as bug-like footprints found by Xiao and his team in a series of digs from 2013 to 2018 in the Yangtze Gorges area of southern China, and date back to the Ediacaran Period, well before the age of dinosaurs or even the Pangea supercontinent. What sets this find apart: The preserved fossil of the animal that made the trail versus the unknowable guesswork where the body has not been preserved.

“This discovery shows that segmented and mobile animals evolved by 550 million years ago,” Xiao said. “Mobility made it possible for animals to make an unmistakable footprint on Earth, both literally and metaphorically. Those are the kind of features you find in a group of animals called bilaterans. This group includes us humans and most animals. Animals and particularly humans are movers and shakers on Earth. Their ability to shape the face of the planet is ultimately tied to the origin of animal motility.”

The animal was a millipede-like creature a quarter-inch to an inch wide and up to 4 inches long that alternately dragged its body across the muddy ocean floor and rested along the way, leaving trails as loing as 23 inches. The animal was an elongated narrow creature, with 50 or so body segments, a left and right side, a back and belly, and a head and a tail.

The origin of bilaterally symmetric animals — known as bilaterians — with segmented bodies and directional mobility is a monumental event in early animal evolution, and is estimated to have occurred the Ediacaran Period, between 635 and 539 million years ago. But until this finding by Xiao and his team, there was no convincing fossil evidence to substantiate those estimates. One of the recovered specimens is particularly vital because the animal and the trail it produced just before its death are preserved together.

Remarkably, the find also marks what may be the first sign of decision making among animals — the trails suggest an effort to move toward or away from something, perhaps under the direction of a sophisticated central nerve system, Xiao said. The mobility of animals led to environmental and ecological impacts on the Earth surface system and ultimately led to the Cambrian substrate and agronomic revolutions, he said.

“We are the most impactful animal on Earth,” added Xiao, also an affiliated member of the Global Change Center at Virginia Tech. “We make a huge footprint, not only from locomotion, but in many other and more impactful activities related to our ability to move. When and how animal locomotion evolved defines an important geological and evolutionary context of anthropogenic impact on the surface of the Earth.”

Rachel Wood, a professor in the School of GeoSciences at University of Edinburgh in Scotland, who was not involved with the study, said, “This is a remarkable finding of highly significant fossils. We now have evidence that segmented animals were present and had gained an ability to move across the sea floor before the Cambrian, and more notably we can tie the actual trace-maker to the trace. Such preservation is unusual and provides considerable insight into a major step in the evolution of animals.”

The study was supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China, the U.S. National Science Foundation, and the National Geographic Society.

Dickinsonia, world’s oldest animals, new study

This 20 September 2018 video from Australia says about itself:

Is Dickinsonia our oldest ancestor?

Scientists from ANU have discovered molecules of fat in an ancient fossil to reveal the earliest confirmed animal in the geological record that lived on Earth 558 million years ago. The strange creature called Dickinsonia, which grew up to 1.4 metres in length and was oval shaped with rib-like segments running along its body, was part of the Ediacara Biota that lived on Earth 20 million years prior to the ‘Cambrian explosion’ of modern animal life.

From the Australian National University:

Mystery shrouding oldest animal fossils solved

March 25, 2019

Scientists from The Australian National University (ANU) have discovered that 558 million-year-old Dickinsonia fossils do not reveal all of the features of the earliest known animals, which potentially had mouths and guts.

ANU PhD scholar Ilya Bobrovskiy, lead author of the study, said the study shows that simple physical properties of sediments can explain Dickinsonia’s preservation, and implies that what can be seen today may not be what these creatures actually looked like.

“These soft-bodied creatures that lived 558 million years ago on the seafloor could, in principle, have had mouths and guts — organs that many palaeontologists argue emerged during the Cambrian period tens of millions of years later¨, said Mr Bobrovskiy from the ANU Research School of Earth Sciences.

“Our discovery about Dickinsonia — and many other Ediacaran fossils — opens up new possibilities as to what they actually looked like.”

Ediacara biota were strange creatures that lived on the seafloor 571 to 541 million years ago. They grew up to two metres long and include the earliest known animals as well as colonies of bacteria.

The fact that Dickinsonia and other Ediacara biota fossils were preserved at all in the geological record has been a big mystery — until now.

The team, which includes scientists from Russian institutions, discovered how Ediacara biota fossils were preserved, despite the macroorganisms not having skeletons or shells.

“As the organisms decayed, softer sediment from below gradually flowed into the forming void, creating a cast”, Mr Bobrovskiy said.

“Now we know that what we are looking at is an impression of a soft organic skeleton that may have been anywhere within Dickinsonia’s body. What we’re seeing could be a part of Dickinsonia’s bottom, the inside of its body or part of its back.”

Mr Bobrovskiy said Dickinsonia had different types of tissues and must have been a true animal, a Eumetazoa, the lineages eventually leading to humans.

Co-researcher and RSES colleague Associate Professor Jochen Brocks said the team used a melting cast of a Death Star made of ice to show the physical properties of sediments that enabled the soft-bodied Ediacara biota to be preserved.

“This process of fossilisation could tell us more about what Ediacara biota were and how they lived,” he said.

“These fossils comprise our best window into earliest animal evolution and are the key to understanding our own deep origins.”

Ancient organic matter of biological origin has been tracked in multiple samples of rock spanning over 2,000 million years of Earth’s history, according to researchers: here.

Primitive ponds may have provided a suitable environment for brewing up Earth’s first life forms, more so than oceans, a new study finds. Researchers report that shallow bodies of water, on the order of 10 centimeters deep, could have held high concentrations of what many scientists believe to be a key ingredient for jump-starting life on Earth: nitrogen: here.

DNA, the hereditary material, may have appeared on Earth earlier than has been assumed hitherto. Chemists now show that a simple reaction pathway could have given rise to DNA subunits on the early Earth: here.