The first animals on earth. When the first animals appeared, was the Earth an ice ball? What was the first animal on earth

First life

It's hard to believe, but on planet Earth there are still those very first organisms that played greatest role in the further evolution of living nature. Scientists knew about them as early as the 18th century, but only in the 30s. In the 20th century, the veil of origin and the mystery of their formation were opened. We are talking about stromatolites.

Stromalites

Stromatolite (from the Greek stromatos - bedding, lithos - stone) is nothing more than a dense layered formation in the strata of limestones and dolomites, resulting from the vital activity of colonies of blue-green algae and other microorganisms. Stromatolites have been found on Earth since the Proterozoic, and today it has been established that the most ancient representatives can boast an age of about 3.5 billion years. Moreover, these same representatives have not changed a bit since those times.

In the 30s. The 20th century witnessed one of the most remarkable events in classical biology. On the littoral of Shark Bay (Australia) and on the Atlantic coast Bahamas small reef structures of a previously unknown type were found. Upon closer examination, these turned out to be modern stromatolites!

The result of the activity of cyanobacteria

It was then that it became clear that stromatolite is formed as a result of the vital activity of a unique prokaryotic creature - a cyanobacterial mat. The cyanobacterial mat is a multilayer "carpet", up to 2 cm thick. It consists of cyanobacteria and other microorganisms. But in addition to the fact that the mat consists of layers, they perform different, but strictly distributed, functions. Thus, it is a full-fledged living organism, each part of which clearly performs its functions, and further research has shown that the cyanobacterial mat is one of the most balanced ecosystems in nature.

Stromatolites live in extreme conditions - in caves, very salty lakes and valleys, as well as in hot springs. And this is not surprising, because the conditions of life on Earth were just such, extreme, 3.5 billion years ago. And only thanks to the photosynthetic work of cyanobacteria, the modern atmosphere is rich in oxygen. Here they are amazing, the first living organisms!

The first animal on Earth was Dickinsonia - a kind of soft symmetrical cake, resembling either a feather or a palm branch.

The first animal on earth

Dickinsonia are famous creatures. They lived about 560 million years ago. But were they animals? With this scientific world couldn't decide. Some considered the “cakes” to be plants, others to be mushrooms, others to be lichens, and some did not “hold” Dickinsonia as independent creatures at all, but believed that these were colonies of bacteria.

Dickinsonia fossilized.

Individual representatives of the "mystery of nature" reached almost one and a half meters in diameter. But there were also small ones - a few millimeters.

Dickinsonia oval cake - this is what it looked like when it was alive 558 million years ago

The remains of two Dickinsonias were taken from a cliff located in Pomorie. The study showed that organic matter was preserved on the fossils. Scientists have determined their composition. And found a high concentration of cholesterol. It meant only one thing: Dickinsonia were animals. After all, only representatives of the animal world - cholesterol - produce it.

The current discovery of paleontologists indicates that the first animals appeared long before the so-called Cambrian explosion, which happened about 540 million years ago - then the living creatures suddenly bred. Dickinsonia "wound up" much earlier - at least 20 million years.

Dickinsonia led what is called a sedentary lifestyle. But their descendants soon moved on, growing legs. And this happened, as it turned out, also many millions of years earlier than it was commonly believed.

The evolution of life on the planet began more than three billion years ago, some scientists say that even more than four billion years. It was then that the first organized ecosystems arose, however, these were microbes and bacteria, and mammals were still very far away. So what were the first animals on Earth?

The very first

The oldest traces of animal life on Earth are about a billion years old, and ancient fossils the animals themselves are about 600 million years old.

The first animals that appeared on the planet were microscopically small and soft-bodied. They lived on the seabed or in bottom silt. These creatures could not be petrified, so the only indication of their stay on Earth is the remains of their holes or passages. The individuals were very resilient, it was they who gave rise to the Ediacaran fauna - the first known animals on the planet.

Ediacaran fauna: light at the end of the Vendian tunnel

The Ediacaran fauna takes its name from the Ediacaran Hills that are found in Australia. Here, in 1946, unusual fossils were discovered, outwardly somewhat similar to modern jellyfish, worms and corals. They were small - an average of 2 centimeters in diameter.

At first, scientists decided that the find belongs to the Cambrian period: it was then that the rapid development of the animal world began (approximately 570 million years ago). But upon closer examination, it was possible to establish that these fossils are even older and belong to an earlier period - the Vendian. This was a real discovery, since no one knew for sure whether life existed during this period.

Then representatives of the Ediacara fauna were found in different parts of the world: in Namibia, Russia, Greenland. But despite the findings, biologists are still trying to figure out what happened to them.

This is what one of these ancient animals, Kimberella, supposedly looked like:

Scientists believe that these are the direct ancestors of modern jellyfish and molluscs.

What did the Ediacarans look like?

The structure of the first animals in the world was the simplest: they had no limbs, head, tail, mouth and digestive organs. Ediacaran creatures didn't do much bright life)) at that time the planet was safe, there were no predators yet, so they didn’t even have anyone to defend themselves from.

It is assumed that they simply absorbed organic matter from the water with their whole body. Moreover, some of them were symbiosis with algae, and outwardly, many of the creatures were very similar to plants.

So, for example, the most big creature was Dickinsonia.

Some individuals reached a meter in length, but usually did not exceed one centimeter in thickness. They had a flat, bilaterally symmetrical corrugated oval body. Such a rug.

Scientists have not decided which group it belongs to: some consider it the ancestor of animals, someone says that it is a type of fungus, and still others claim that it generally belonged to a class of creatures that do not exist today in the kingdom of nature. And her modern relatives were never found.

And what happened after the first animals in the world?

The next period in the history of the development of life on Earth is called the Cambrian. It began about 570 million years ago and lasted about 70 million years. It was here that an astonishing evolutionary explosion took place, during which representatives of most of the major animal groups known to modern science first appeared on Earth. And this happened due to good climatic conditions.

In the Cambrian period, huge plumes and continental shoals existed on the planet. There were ideal conditions for life: the bottom covered with a layer of soft silt, and warm water. A lot of oxygen has already formed in the atmosphere (although much less than now). The development of hard land covers led to the emergence of new life forms, such as arthropods - the first arthropods.

Animals needed new ways to protect themselves from new highly organized predators. As a result of evolution, creatures developed means for protection, respectively, predators had to develop new methods of hunting in order to overcome the resistance of the victim.

During the Cambrian period, the sea level repeatedly rose and fell, species died out, others came in their place, who had to adapt to new living conditions and ways of subsistence.

The animal world became more diverse, and all more populations could exist next to each other without claiming the food resources of their neighbors.

First land plants and animals

WHAT THE FIRST PLANTS LOOKED LIKE Once upon a time, our planet was inhabited by plants that had only a stem. They were attached to the ground with special outgrowths - rhizoids. These were the first plants to reach land. Scientists call them psilophytes. This is a Latin word. Translated, it means "naked plants". The psilophytes really looked "naked". They had only branching stems with outgrowths of balls in which spores were stored. They are very similar to the "alien plants" that are depicted in illustrations for fantastic stories.

Psilophytes became the first land plants, but they lived only in swampy areas, since they did not have a root, and they could not get water and nutrients deep in the soil. Scientists believe that once these plants created huge carpets over the bare surface of the planet. There were both tiny plants and very large ones, taller than human growth.

THE FIRST ANIMALS ON EARTH The oldest traces of animal life on Earth date back a billion years, but the oldest fossils of the animals themselves are approximately 600 million years old and date back to the Vendian period. The first animals that appeared on Earth as a result of evolution were microscopically small and soft-bodied. They lived on the seabed or in bottom silt. Such creatures could hardly be petrified, and the only clue to unraveling the mystery of their existence is indirect traces, such as the remains of burrows or passages. But despite their tiny size, these most ancient animals were resilient and gave rise to the first known animals on Earth - the Ediacaran fauna.

The evolution of life on Earth began with the appearance of the first living being - about 3.7 billion years ago - and continues to this day. The similarity between all organisms indicates the presence of a common ancestor from which all other living beings descended.

ALL

Earth is a rotating ball of hot, molten rock covered with a thin outer crust. There are cracks in the crust called fault lines that divide it into large and small sections called plates.

plate movement

plate movement

The molten rock below the plates causes them to move at an average speed of 2 cm per year. As they move, they rub against each other.

When two plates collided, one could go under the other, and the resulting lowland eventually filled with water, forming a lake, sea or even an ocean. In the past, where two or more plates collided, their edges would rise to form mountain ranges.

It is believed that life on Earth originated about 4 billion years ago. But how it happened, we don't know for sure. Most scientists believe that from a mixture of simple substances - water, nitrogen, hydrogen, ammonia, hydrogen sulfide, carbon dioxide and carbon monoxide - more complex compounds were formed. From them, the main “bricks of life” accidentally arose: nucleotides(elements of the hereditary substance) and amino acids.

Scholars debate where this first occurred. Where was that "chemical laboratory" in which it was possible to "create life"? Most believe that in the sky. At that time, the entire sky was covered with clouds. It was here that the most important organic compounds were formed - under the influence of electrical discharges and strong ultraviolet radiation from the Sun (at that time there was no barrier for it in the form of an ozone screen). Heavy rain showers washed these compounds into the ancient Ocean. There the evolution continued. This is one of the hypotheses. Other scientists, on the contrary, are looking for a solution to the mystery at the bottom of the Ocean, near hot volcanic springs. There, according to their ideas, substances necessary for the origin of life accumulated, and conditions were created in which chemical processes could take place.

It is not yet clear what prompted further development. Biologists believe that on the cooling Earth from simple chemical substances the hereditary substance and proteins were formed. What happened next?

Why did the “bricks of life” themselves line up in such a way that they created organisms that began to absorb nutrients and multiply? For now, we can only speculate about this.

In some ways, all scientists agree: life originated in water, the first living organisms were the most primitive, and they improved very slowly. At some point, one of these organisms was enveloped by a thin membrane - this is how the "primary cells" appeared. Gradually, the abilities of the cells multiplied. Some have reached the highest stage of development: they have learned to hide the hereditary substance in a special cell nucleus. Then some cells began to absorb other, smaller ones. The captives, caught inside the host cell, "worked" for him. These complex cells - they are called eukaryotes - subsequently created cell colonies. From such colonies, multicellular organisms developed: plants, animals, and, finally, humans.

Life in the Earth

4600 million years ago the planet Earth was formed. At first it was hot and dry. It took a very long time before seas and oceans formed on it.

3500 million years ago, the first living creatures appeared in the oceans. They were so small that they could not be seen, like modern microbes that cause disease in humans.

Simple animals such as jellyfish and corals, as well as simple plants such as algae, lived 700 million years ago.

400 Millions of years ago, the first land plants appeared on Earth. Panzer fish and other animals lived in the seas.

340 million years ago in swampy forests covering most land, lived insects and amphibians.

230 Dinosaurs lived on Earth millions of years ago. They were terrestrial reptiles. There were also flying and aquatic reptiles.

The first mammals were very small and lived 225 million years ago.

The first monkeys lived 35 million years ago. Monkeys like the gorilla are closely related to humans.

The first human fossils found in Africa 2 million years.

fossils

Animals and plants that had died long ago were mostly decomposed. But sometimes their hard parts, such as bones, are preserved as fossils in rocks.

Fossils can be used to judge what plants and animals lived on Earth many years ago. Some of them, such as corals and sea lilies are still living on Earth.

But much more species, such as ammonites, unfortunately died. If all members of one species of living beings have died, then this species is called extinct or extinct.

Where plants and animals live today

Most of the land on Earth was once united. As the plates moved, seas, oceans, and mountains formed. This did not give animals the opportunity to move all over the earth. That is why different living beings have appeared in different places today.

Australia separated from Antarctica 55 million years ago. And now animals like kangaroos, wombats and platypuses live only in Australia.

Wombats- digging forest animals. They are a little bigger than badgers

Some animals give birth to very tiny cubs, which are in their mother's pocket for a long time. These are marsupials, such as kangaroos.

There are many camel-like animals all over the world. Their ancestors were widespread on earth when it was one.
When the ocean appeared, they separated. Over millions of years, each group of animals evolved separately.

The very first animals

» Extinct animals » The very first animals

Life has existed on our planet for at least 3.8 billion years. The stone chronicle of the Earth has preserved for us many traces of the existence of its former inhabitants. People from ancient times find them here and there. Perhaps the tales of dragons, giants and other monsters appeared for a reason, but thanks to the amazing finds of the bones of giant dinosaurs, mammoths, whales. Bones, shells, shells are the most widespread remains of extinct creatures. Usually they are to some extent mineralized, that is, turned into stone, which is why they are called fossils. To refer to this phenomenon, the Latin word "fossils" is also used, which means "fossils".

Who are these animals?

Animals are multicellular organisms that feed on other organisms, and as such, they usually have digestive organs. In addition, animals, unlike plants and fungi, are mobile, since food must be sought, and sometimes even caught and overtaken.

And in order to search, catch and catch up, in addition to mobility, sensory organs are also needed - in order to see prey, catch its smells and taste it.

When did animals appear?

There were no animals among the first inhabitants of the Earth! For at least 3 billion years our planet was inhabited only by microorganisms, mainly bacteria. Scientists call this time the cryptozoic era. hidden life. The first multicellular organisms appeared about 1 billion years ago, but there were probably no animals among them yet. However, already 800 million years ago they undoubtedly existed: in rocks of this age, the most ancient trace paths were found - evidence of the movement of organisms along the bottom of ancient seas.

zemka2017-04-27 06:25:44

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The very first living thing on Earth

First life

It's hard to believe, but on planet Earth there are still those very first organisms that played the greatest role in the further evolution of living nature.

Scientists knew about them as early as the 18th century, but only in the 30s. In the 20th century, the veil of origin and the mystery of their formation were opened. We are talking about stromatolites.

Stromalites

In the 30s. The 20th century witnessed one of the most remarkable events in classical biology. On the littoral of Shark Bay (Australia) and on the Atlantic coast of the Bahamas, small reef structures of a previously unknown type were found. Upon closer examination, these turned out to be modern stromatolites!

The result of the activity of cyanobacteria

Victoria Visicheva, Samogo.Net

Ancient animals of the Earth

The ancient animals of the Earth are animals that died out for some natural reason before the appearance of man. Sometimes they are called prehistoric animals. Some of them continued to exist even after the appearance of mankind and died out already through our fault.

The dodo or dodo is a large flightless bird. Its modern relatives are birds of the pigeon order. At one time, dodos densely populated the island of Mauritius, ate plant foods, and the only egg was laid by the female dodo directly on the ground. Dodos disappeared only in the 17th century due to the fault of people and the animals they brought to the island.

The most famous ancient animals on Earth are mammoths. This species of elephant lived on our planet about 1.5 million years ago. Judging by the fossil remains, mammoths were larger than their modern relatives and their body was covered with wool. Mammoths ate exclusively plant foods and were desirable prey for primitive hunters. Why mammoths died out, there is no consensus.

Smilodon or Saber-toothed tiger disappeared from the surface of our planet more than 2 million years ago.

Smilodons were larger than modern tigers, and the long saber-shaped fangs on the upper jaw allowed it to hunt thick-skinned rhinos and elephants.

The giant ground sloth Megatherium lived about 2 million years ago on the American continent. The length of his body was 6 meters. Megatherium fed on the shoots of young trees, bending them to the ground with long front paws equipped with curved claws.

Another large flightless bird of antiquity with strong three-meter hind limbs is the moa. Moas lived in New Zealand until the 17th century and were completely destroyed by people.

The epiornis bird, also not flying, weighed up to 450 kilograms, and its height reached 3 meters. According to the assumption, the eggs of these birds could weigh up to 10 kilograms. Back in the 19th century, epiornis could be seen in Madagascar, but due to deforestation rainforest and ruthless extermination today these ancient birds have become completely extinct.

Chalicotherium is an ancient animal of the Earth with a horse's head and claws instead of hooves. Scientists attribute it to the detachment of artiodactyls. In an attempt to get high-lying plant food, chalicotherium on powerful hind limbs could reach up to 5 meters in height.

The ancient animal of the Earth, which, probably, was lucky to survive to this day, is the marsupial wolf. This ancient mammal has a body length of up to 1 meter, plus a half-meter tail length. He lived in Australia, but by the time the Europeans discovered the mainland, he had survived only on the island of Tasmania (sometimes the wolf is called Tasmanian). Since the beginning of the 20th century, no one has seen a marsupial wolf alive, but it is, nevertheless, listed in the Red Book.

And the most mysterious and numerous ancient animals of the Earth are dinosaurs. Their name is translated as "terrible lizards." For 200 million years, they inhabited the earth's land almost everywhere and mysteriously died 60 million years ago. The most likely reason for the extinction of the dinosaurs is the collision of our planet with an asteroid, as a result of which the Earth's climate has changed in a detrimental way for dinosaurs.

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