Scholars such as Scott Evans of the University of California have published a startling discovery in the Proceedings of the National Academy of Sciences that a 550 million-year-old creature found in an ancient cave in Australia's deep sea may be the ancestor of all animals in the world!
<h1 class="pgc-h-arrow-right" > "ancestor of all animals in the world"? </h1>
Scott Evans and other scientists found a strange stone slab near a cave on the deep seabed of Australia with a small, curved hole the size of a grain of rice, which is obviously not naturally formed, and is very likely to be an ancient fossil, so the researchers scanned it and modeled it, and found that the cave in the middle was formed by a worm, and the researchers also found a similar structure of worms!
3D laser scanning
They have a clearly defined head and tail, and also have worm-like left-right symmetry and muscular tissue, which the researchers named "Ikaria wariootia," meaning the ancestors of all animals! Mary DeRoze, a geology professor at the University of California, Riverside, said it was the oldest complex animal fossil they had ever acquired!
This animal is also the oldest left-right symmetrical organism ever found, with both front and side, as well as two symmetrical sides and a head and anus connected by the stomach and intestines. Most of the multicellular organisms discovered early, such as sponges and seaweed, are called the Ediacaran biota (571-539 million years ago), and even the most complex fossils of multicellular organisms are mostly not directly related to modern organisms, such as water lily-like organisms such as Dickinson's, which lack the basic characteristics of most animals, such as the feeding mouth and intestine.
Renderings of Ikaria wariootia
Left-right symmetry is a milestone in the evolution of life, which allows organisms to move themselves purposefully, and this is one of the most common and successful ways of body structure, from worms to insects to dinosaurs, and finally to humans and many other organisms are all left-right symmetrical species, while other symmetries, such as polyps (central symmetry) and sponges (asymmetry), can only exist as lower organisms.
Various symmetrical body type of organism
This left-right symmetric creature called Ikaria wariootia escaped extinction in the Ediacaran period and continued into the Cambrian period (541 million to 485.4 million years ago), which means that they had enough time to evolve their offspring, so it seems not too much to call them the ancestors of all modern animals!
<h1 class="pgc-h-arrow-right" > a brief history of the evolution of life on Earth</h1>
4 billion years ago, the first life on Earth was born, an RNA molecule that could replicate itself, but was later replaced by more efficient DNA, and by 3.8 billion years ago, prokaryotes began to appear, which belonged to single-celled organisms, including archaea, and cellular structures began to appear! In 2017, Quebec, Canada, discovered 4.28 billion-year-old microfilars, which became the earliest direct evidence of life on Earth.
Micro-fossilized stone
In the late days of the Earth's birth, the surface cooled, the atmosphere and oceans began to form, volcanoes continued to erupt, strong ultraviolet rays in the sunlight hit the earth, lightning constantly raged in the air, and these organic molecules gathered together became complex compounds by influencing each other, and eventually self-replicating RNA appeared.
There are many theories about the birth of life, but the most convincing is the Miller-Yuri experiment, a classic experiment that simulated the interaction of various environments in the primordial Earth, which was completed by Stanley Miller and Harold Yuri of the University of Chicago in 1953, and the results of which were published under the title "Amino Acid Formation in the Possible Early Earth Environment" became the most classic experiment on the origin of life in modern textbooks.
Miller-Yuri experiment
Blue bacteria that can photosynthesize 2.8-2.5 billion years ago appeared, absorbing carbon dioxide and discharging oxygen, which directly led to the great oxidation event 2.5 billion years ago, and oxygen-loving organisms began to dominate! Multicellular organisms began to appear 1.5 billion years ago, such as eukaryotic algae in the ocean! It evolved to sexual reproduction 1.2 billion years ago.
Multicellular animals began to appear 665 million years ago, a sign of the transformation of plants into animals! Complex multicellular organisms began to appear in the Ediacaran biota 550 million years ago, and "Ikaria wariootia" is in this era. The Cambrian explosion of life that followed gave rise to the phylum of all animals today.
The earliest vertebrates began to appear 520 million years ago, and fish began to appear 480 million years ago. 375 million years ago, fish began to develop meat fin support and began to land, and it was at this time that the long-handed fish discovered and confirmed by Canada were born a while ago!
Dinosaurs began to appear 251 million years ago, the earliest mammalian climbing progenitor appeared 125 million years ago, and the last common ancestor of humans and mice appeared 75 million years ago. 66 million years ago, dinosaurs went extinct!
37 million years ago, the ancestors of the proto-monkey suborder began to appear, 13 million years ago, human ancestors formed from the ancestors of orangutans, 3.7 million years ago Australopithecus began to appear, 27,000 years ago Neanderthals became extinct, and only Homo sapiens remained in the human race! 15,000 years ago, the Ice Age ended and the Earth entered a warm interglacial period!
Ten thousand years ago, mankind entered the era of farming, in the eighteenth century mankind entered the era of the Industrial Revolution, and in 1969 the Americans landed on the moon!