The process of formation and evolution of life on Earth

Earth - our planet, is different from what we still see today, it began its life from a terrible sphere that even the most horrible scenes in movies cannot match. equal. So what made our life and civilization?

With the modern model of the Solar System and the oldest samples on Earth found to be more than 4 billion years old (Canada's 4.03 billion and 4.4 billion in Western-Central Australia), scientists today it is possible to conclude that the Earth was formed about 4.7 billion years ago, as a result of the gravitational formation of millions of large and small rocks and dust and gas on a strip of material around orbit. Sun.

At first, the Earth was just a hot, dead planet, heavy metals sinking in and melting, pushing light materials up and cooling down. The Earth is now shaped like a giant black sphere with bright cracks due to the melting of the material. It is these stains that will continue to exist for billions of years, often becoming a decisive factor for the survival of life on the planet.

At first, the Earth was just a hot, dead planet.

4.3 billion years ago, a planet of the size of Mars named Theia (co-formed in the early stages of the Solar System) headed towards Earth. The impact is a real disaster, but it is also a prerequisite for our life later. First, it makes the density of matter on Earth become more uniform, just like when you juggle a jar of many candy at the same time. Next . it forms the Moon. The matter from the surface of both planets shot up into space, forming a strip of matter moving around the Earth's orbit, like Saturn's belt and large planets today. Gravity once again plays the role of the creator, it gathers the debris, forming the Moon.

At this time, the Moon is very close to Earth and the Earth turns very fast. If things go on like that, life will be hard to form. But thanks to the Moon's presence, the Earth turns slowly due to the influence of gravity, while centrifugal force pushes the Moon away, avoiding the tides that are tens of times stronger than the waves. The most terrible god of this day. It was about 4.1 billion years before the ocean and atmosphere (without oxygen) were forming.

1 planet with the size of Mars named Theia (co-formed in the early stages of the Solar System) hitting the Earth.

About 4.1 to 3.8 billion years ago , the Earth was filled with the ocean due to the cooling of the Earth allowing the existence of liquid water. Small asteroids and meteorites continuously bombard the Earth, they are remnants in the early days of the Solar System. It is these meteorites that carry hydrated crystals and even the simplest organic compounds into the ocean, where life will arise later.

3.8 billion years ago, the Earth entered the Archaean era. This is the middle period of the pre-cambrian period. From the first organic compounds that come from meteorites that attack Earth, amino acids form in the ocean, the first simple cells are formed. Unlike us today, they are made on the basis of RNA molecules (Ribonucleic acid, different from DNA, which is the current Deoxyribonucleic acid made up of plants and animals). Today we have found fossils of the first life forms with the largest age of 3.5 billion years. The first cells from the beginning are unicellular life forms, which gradually merge into thicker layers than stromatolites, which are the first life forms of photosynthesis that provide oxygen to our planet. The first simple glucose compound (sugar) has also formed.

3 billion years ago , the ocean was filled with oxygen, the iron in the ocean was oxidized and sank into iron ore, the structures we have today are made of this 3 billion year old ore. .

2.5 billion years ago, the Proterozoic period (pristine) began. This is the first development of early species on Earth, the last stage of pre-Cambrian times. The first multicellular plants appeared about 1.2 billion years ago with more complex structures from DNA instead of RNA.

However, the development of life has not been long before it is forced to stop. Time almost stopped when the Earth entered the longest and most intense global freezing period in history. 850 million years ago, the oxygen density was too high in the atmosphere to prevent the absorption of sunlight, the Earth was not heated, so it cooled and froze gradually. The more ice there is, the more reflected sunlight is when the whole planet is like a giant mirror that does not absorb any light at all.

The whole Earth was then a giant ice sphere, without a trace of life.

This period lasted more than 200 million years. We know that today's human beings with a seemingly very long history actually exist in real civilization and wisdom at the end of the ice age, about 15-20,000 years ago. While the whole period of freezing the planet has now reached more than 200 million years. The whole Earth was then a giant ice globe, without trace of life, of the Sun's warmth, any rays from the Sun being reflected back into space.

630 million years ago , the source of molten lava in the Earth was awakened, becoming the savior of life on the planet. Volcanoes after hundreds of millions of years of sleep have woken up and erupted, they break some of the freezing points on the surface of the Earth, spray lava onto the surface, and most importantly, carbon dioxide . As we all know, carbon dioxide is the cause of the greenhouse effect , and right now it is the savior of life on Earth. The air that absorbs the Sun's temperature, along with the eruption of lava, causes the ice to melt away, allowing the deepest forms of life in the ocean to survive. This melting process lasts for several million years.

580 million years ago , multicellular plants were quite common and also the first period of mollusks, today we have found fossils of molluscs of age equivalent to the period this.

540 million years ago , oxygen continued to be filled with atmosphere and the upper layer of the atmosphere directly received sunlight, a layer when newly formed from oxygen, which was ozone , which prevented radiation radiation. ultraviolet penetrates into the atmosphere, and this is the condition for life to invade the ground (at this time the first continental plates appeared).

About 530 million years ago, the Earth entered the Paleozoic period , the beginning of the first century was the Cambrian period. This is an explosion of biological growth, lasting about 30 million years, called the Cambrian boom. Under the sea, more complex animals appear, most notably the three-lobed beetles and its relatives. In addition, this is the first time the presence of predators, species that directly attack other species, feed instead of eating small plants or floating corpses. For example, in the picture below is an Anomalocaris that is about to kill its prey as a three-lobed bug.

Anomalocaris.

505 million years ago, the next stage of plant and animal development began, this is the 2nd century Paleozoic, Ordovician (Ordovician) . The ocean invaded the entire northern part of the Earth and the development of the concentrated continent in the southern continent was Gondwana. This is a period of strong development of mollusks and especially the explosion of fish. The first fish species appeared to dominate the ocean from this period to the Silur period (Silurian, 440-410 million years ago) and Devon (Devonian, 410-360 million years ago).

Devon, 410 million years ago , a fish called Tetrapods came into contact with the land and used its fins to crawl up. After millions of years of evolution, they rose to the ground, evolving into the first terrestrial animals, followed by Ichthyostega . In addition, this is also the development period of insects quite similar to today like dragonflies or arthropods, but with much larger sizes. Not only that, the plants also grow in gigantic sizes, up to tens of meters high due to the high concentration of oxygen in the air.

A fish called Tetrapods.

From 360 million to 286 million years of Carbon (also known as coal century). This is the period when a series of trees die and lie in the ground, forming today 's coal mines. Most importantly, this is the period when animals start laying eggs on the ground. We should know that before this carbon phase, even animals began to invade the terrestrial world such as some reptiles and frogs but still have the habit of laying eggs under water due to the young in the eggs needed. enough moisture can survive until the end of life. But by this time, reptiles had evolved to be able to produce water-bearing eggs that directly supply the young. The first two species of ancestors of the later generation of reptiles were Hylonomus and Paleothyris.

A Hylononus.

Large trees die to form coal, while an equally large generation appears instead, which are clusters of moss as high as 30m, horsetail and ferns above 15m, they flooded across the continent of Gondwana.

From 286 to 248 million years ago, the Earth entered the final period of Paleozoic Paleozoic, the Permy (Permian). This is a very important period in the development of animals. Some reptiles evolved into the early stages of mammals, such as the therapsids in the lower image that evolved from the Dimetrodon species, which had faces and teeth very similar to the mammals of the day. Now, it is also one of the feared predators of the Permy era. Unfortunately, mammals did not grow so easily, therapsids and many animals (mostly reptiles) at the time were victims of the most terrible extinction disaster in Earth history: Great Permian extinction.

Species of Therapsids.

Up to now, there are still many disagreements about the cause of this disaster, but most of the opinions suggest that the cause of the great extinction is the merging of the two continents of Laurasia and Gondwana into Pangea continent. The collision disturbs the topography of both major continents, leading to continental earthquakes and volcanoes that destroy organisms. But where the most devastating destruction this time is the ocean creatures, up to 95% of species have permanently disappeared after this extinction.
This great extinction marked the end of the Permian period, transitioning to the next period called Mesozoic.

248 million years ago was the beginning of the Mesozoic era , when the great extinction was over. In the ocean as well as on land, the transformation has stopped, but natural conditions are no longer the same, and some species appear to be better adapted to other species, they grow to become dominant rulers. fine. The first time of Mesozoic was the Triassic period (some Vietnamese documents often translated as the Tam Diep century), which marked the beginning of what people called dinosaur dynasties . This is the most flourishing period in the history of reptiles. Mammal ancestors such as Cynodonts continue to exist and maintain mammal explosion and the end result is us later.

Child Cynodonts.

However, during this Triassic period, mammals and even fishes proved to be extremely low compared to the dominance of dinosaurs. They are ubiquitous in size from small to large, and in enough life forms. While on the ocean floor, the Ichthyosaurus rulers or Nothosaurus for a long time, the dinosaurs were more prosperous on the ground. They are divided into three main groups: theropods (predators like T-rex, Coelophysis or Allosaurus), the sauropod group consisting of long-necked lizards like Apatosaurus, Mamenchisaurus and finally the ornithischia n group of species like Triceratops ( 3-horned dinosaurs, Stegosaurus (armor dinosaurs) or even Iguanodon as you have seen in Walt Disney's famous Dinosaur movie. The picture below is a T-rex (Tyranosaurus Rex), the most famous hunting predator of the Triassic period.

T-Rex tyrant dinosaur.

213 million years before the Jurassic began. This is the middle stage of Mesozoic. Pangea once again broke into Laurasia and Gondwana. In the cracks, there is the destruction of a range of organisms including plants and fish and marine animals.

They settle down and form oil fields today, this is a very important point in the geological history of the Earth and contributes significantly to our modern world today.

Meanwhile on the ground the reptiles continue to grow. By the middle of the Jurassic period they had dominated both the air, the ground and the ocean with the number of species increasing greatly compared to the Triassic period. Under the ocean, plesiosaurs appear and rule the sea floor.

A Plesiosaurs.

While dominating the sky is pterosaurs , winged lizards. However, they are not the ancestors of birds later. Today's birds began as well from the Jurassic period, an evolutionary carnivorous dinosaur, growing feathers to become a transition species between reptiles and birds. The Archeopteryx are the ancestors of today's birds.

Child Archeopteryx - ancestor of birds today.

Mammals of this period are just small animals like today's mice, they must live in hiding to escape the dinosaur hunt.

145 million years ago, the Earth entered the Cretaceous period (some Vietnamese documents are often referred to as the Cretaceous period) , this is the last stage of dinosaurs. and also the last century of the Mesozoic era.

The most remarkable point of this period is the emergence of flowering plants, pollinated by insects, replacing the old generation of trees, including mainly ferns and conifers. The dinosaurs have no longer prospered as before due to the change of such vegetation. However, they were still unbeaten rulers until 65 million years ago.

The vast majority of current opinion is in the assumption of a destructive asteroid, since it has evidence of Iridium (something that can only come from Earth) with a life span of about 65 million years found in China. USA, Gulf of Mexico region. This hypothesis suggests that an asteroid with a diameter of more than 10 km in the Solar System has rushed towards Earth. The terrible impact created today's Gulf of Mexico and the largest tsunami and earthquake in the entire Mesozoic era.

An asteroid with a diameter of more than 10km in the Solar System rushed towards Earth.

More importantly, it causes major climate changes . The formidable volcanic eruption and meteorite attacks kill a series of large animals. Volcanic dust and soot, as well as collisions cover the sky, preventing sunlight from reaching the ground, causing mass deaths of trees. All depleted food supplies and unexpected temperature changes are the most important factors leading to the extinction of dinosaurs.

However, compared to the level, this collision is not comparable to the great Permian extinction. Therefore, there are still small reptiles, birds survive due to less demand for food, as well as easily hide the effects of disasters. And most importantly, our mammalian ancestors, they have survived through disaster to enter the next phase of Earth's history.

Great Cenozoic (freshman)

A world away from dinosaurs has become empty for a long time when birds have not yet grown strongly and mammals have become accustomed to hiding under deep caves to avoid dinosaurs. Until then, nearly 60 million years ago, new mammals landed and developed into forms from predators to prey, and their small enemies at that time were giant carnivorous birds. giant

About 55 million years ago at the end of Palaeocene (a part of Cenozoic) , primates began to appear in tropical and subtropical regions with more flexible characteristics than other species allowed them to like. suspected of living environment: the front foot (later the hand) has 5 fingers with the opposite thumb to the other 4 fingers to handle, pass branches; Flexible neck allows observations from many directions . It is our first ancestor today.

At the time of Eocene just after Palaeocene from 55 to 33.7 million years ago, the climate was warmer, the tropical forest expanded from the equator while the ice concentrated at two poles, especially Antarctica, with the appearance of many plants and animals are similar to the day in which most notably ungulates and some primates are closer to us.

It is noteworthy at this time that two groups of ungulates are Artiodactyla (ancestors of modern deer) and Perissodactyla (ancestors of horses and rhinos), they are common animals of this period. The horse at that time was quite small, just like small dogs now. Later they became extinct, leaving only a few survivors to develop into horses, zebras and rhinos today.

The Mesonychids.

An interesting and important animal branch in the history of life development is the Mesonychids shaped like dogs and hyenas, which are predators of more than 30 million years ago. Due to their convenient adaptation to the water environment, they leave the ground, adapt to the new habitat and later evolve into today's whale.

The true ancestors of humanity only appeared about 3.7 million years ago, which is the farthest time that we can now record the ape's footprints that were able to walk on two feet. . This species is called Australopithecus , growing in African forest areas. The desertification of this continent makes the forest turn into desert or steppe, without trees to climb, the Australopithecus species gradually evolved to be able to adapt to the lack of tree tops.

Australopithecus - the progenitor of humans.

Australopithecus later evolved into Homo habilis with a more human-like level, and then further than Homo ergaster, then Homo erectus with less hair, concentrating only on the head, body functions were quite similar. with people today.

Homo erectus is thought to be the first ancestor in our human form today, with a brain about 74% of the modern human brain. That was about 1.8 million years ago.

Until 100,000 years ago, the first intellectual person actually appeared, those of sapien Homo . They are the most intellectual branch of development among the genus of Homo apes. With the desertification of Africa, they crossed the border between Africa and Europe, scattered across Europe and Asia (originally the Middle East) today and live with exotic animals in time of ice age like Mammoths (mammoths) or mammals are more or less different from today's animals.

Mammoth.

When the age of dynasties entered the end of the period of about 12,000 years ago, people truly entered their time with social organizations from small to large, from simple to complex. If the dinosaurs that once dominated the Earth for the longest time in the history of this planet, on the contrary, we humans occupy it for too short a time but are a species with tremendous growth. most about the population, the development of society and science and technology. And what we have today, including the lines you just read, is the result of all this process!

Dang Vu Tuan Son