A timeline linking the universe, earth history, and the evolution of species

This is a website about Big History. Big History is an emerging field that, through an interdisciplinary approach to the study of history, aims to provide as big a perspective as possible, helping people to examine from a higher dimension our place as a special species in the story of the universe.

About 13.8 billion years ago, something called the "singularity" appeared, and it seemed to begin to create the "basic context" in which our world was constructed: time, space, matter, and energy, which we also (tentatively, depending on the theoretical physicists) saw as the starting point for "all stories.

The "Planck period" is the first "era" of the universe, a "creation" moment described by physicists and full of infinite imagination: the universe emerges from the background of "quantum fluctuations", and "space-time" From a very small, extremely dense initial state, it expands rapidly and cools down. When the temperature is low enough, gravity, as an independent form of energy, begins to act on the once "microscopic" world.

The independence of the "strong force" is another important "phase transition" that occurred in the early universe ". In this very early period of the universe, there was an exponential "surge", which instantly turned the original "microscopic universe" into a macroscopic existence, and the speed of space expansion even far exceeded the speed of light.

After the "surge", because the electromagnetic and weak forces have not yet separated, this equally short period of time is called the "electroweak period". Previously, due to the high background temperature, the concept of "particles" may not have any meaning, but with the expansion of space and the decrease of temperature, the first batch of particles will appear in the void, which are the "smallest units" to build the material world ".

At about 0.000000000001 seconds of the cosmic epoch, the electromagnetic and weak forces completed their separation and the electroweak period ended. At this point, the four fundamental forces of nature can all act independently. After that, as the background temperature continued to decrease, the universe experienced a transition period with "quark-gluon" as the main form; when the temperature was further reduced, the "hadrons" that constituted our material world could also exist. This new era It is also called the "Hadron Period".

After the singularity, the universe finally crossed the most "magnificent" second. The energy density of the cosmic background continues to drop sharply, having cooled to about 6 billion K, and the "hadron era" ends, replaced by the "leptonic era". Compared with the previous cosmic period, this era is very long, for three minutes. Among the most interesting particles generated during this period, electrons are included. The electron is another element that makes up the nucleus of an ordinary atom.

After the end of the "leptic period", the subsequent cosmic period is called the "primary nucleosynthesis period". The so-called "nuclear synthesis" is through the already existing hadron (proton and neutron) to create the process of atomic nucleus. Nucleosynthesis begins approximately 3 minutes after the singularity and ends at approximately 10 minutes.

The universe continues to cool, the rhythm of the violent "phase change" slows down, and the control of the universe changes from "energy" to "mass". In a more "mild" environment, the simplest atoms in the list of chemical elements are slowly becoming stable.

In the 380000 year of the cosmic era, photons were completely decoupled, creating an extremely magical scene throughout the universe: the endless space-time was suddenly filled with bright light! This is the first ray of light (although not "visible light") that can shine and reflect the whole world since the beginning of time, so that the world composed of matter is completely presented in the void for the first time, and the universe ushered in the dawn!

Although the "background radiation" that declares the "dawn" of the universe can travel through the entire space-time, it is not visible light. For mankind, the universe is still dark, and there seems to be nothing in the vast void. This period is also called the "dark period" of the universe ". But darkness shapes the hope of the future.

In the 0.4 billion year of the cosmic era, the "end of the dark age", the once dark universe was suddenly illuminated by the first stars that bloomed like fireworks, so there was light! All stars are shaped by gravity, and they also use life to resist gravity; gravity ignites the heart of the star, and finally buries all the glory. This is a violent and romantic process, but it creates all the possibilities for future life......

The early universe was full of hydrogen and inert helium, while carbon, oxygen, nitrogen, phosphorus and higher atomic number elements had not yet appeared, let alone water or complex molecules. And there is no mechanism in the dark universe to produce the complex chemical elements that build our bodies and the world around us. But stars have changed the universe, creating all the possibilities for the future with their incredibly magnificent lives.

About 9 billion years after the Big Bang, near the region of the universe where we are now, there was a supermassive star that reached the end of the journey; at the last moment of its glorious life, it seemed unwilling to leave like this. A violent supernova explosion poured terrible energy into the universe and created a large number of metal elements.

About 4.6 billion years ago, the sun was born; over the next tens of millions of years, the solar system gradually took shape. When we talk about the "solar system", the real focus is not the sun, but the planetary system that orbits it: the most complex things in the universe are actually hidden in a circle of "dust" made up of planets and other tiny objects.

The earth was born about 4.55 billion years ago, tens of millions of years later than the sun. She is about 8 light minutes from the sun and has a period of revolution of 365.24219 days. There is no doubt that this blue planet is the most special object in the universe. For about 4 billion years (which is almost close to the 1/3 history of the universe), she miraculously maintained a relatively stable state, allowing life to never Interrupted, which finally gave mankind and civilization a chance to emerge.

The Paleozoic refers to the period between the birth of the earth about 4.55 billion years ago and the "oldest known rock formation" about 3.8 billion years ago, also known as the "dark age" of the earth ". Its name comes from the place where the dead live in ancient Greek mythology-the underworld. Yes, the earth has a violent infancy.

4.5 billion years ago, the nascent Earth was constantly colliding with meteorites and growing up in the process. It is estimated that the process from the asteroid to the "original earth" is very rapid, and may only take hundreds of thousands of years. This is also the most violent period of the earth: many asteroids and asteroids are constantly colliding. Among them, a planet named "Theia" almost destroyed the earth, but unexpectedly brought the moon.

According to the "asteroid theory", planets such as the Earth form very quickly, perhaps in tens of millions of years. Soon, the heat dissipated into space, and the Earth formed a hard black basalt crust. It is likely that within 0.1 billion years after the "big impact" that formed the moon, the original ocean and atmosphere gradually covered the black surface, allowing the planet to evolve into a blue star.

At least 3.8 billion years ago, the first life appeared on the earth; perhaps the appearance of the first life form was unexpected, but once it appeared, like a wildfire on the dry grassland, life would quickly occupy every part of the planet. Can survive in the corner. Since we don't know if there are other life forms in the universe, the emergence of life also makes the earth unique. It provides a small "point" for the universe to expand to higher latitudes. After all, the living universe and the inanimate universe should be completely different.

What really leads us to the origin of life are the forms of life that are now known. We can divide all known life into categories according to their characteristics, and then find a theoretically possible "recent common ancestor", which has a nice name-Luka (LUCA).

The earliest forms of life should have depended entirely on the chemical energy of the rock, which greatly limited the form of microbial life. About 1 billion years into the geological epoch, a group of microorganisms known collectively as "cyanobacteria" (or cyanobacteria) evolved "oxygenated photosynthesis," converting sunlight and water into energy, releasing oxygen in the process. This completely changed the appearance of the planet.

According to the "asteroid theory", the formation of the earth is very fast, it may only take tens of millions of years. Soon after its birth, the earth had a solid shell. Although the ocean and atmosphere may have experienced the process of recovery, they can exist stably as early as more than 0.1 billion years after the big impact. Continents and mountain ranges formed later, probably 0.5 billion to 1 billion years after Earth's formation, because they relied on less dense granite that drifted over the mantle and basalts, and the formation of granite relied on the ocean to provide large amounts of water.

Microbial activity has changed the world. For nearly 3 billion years, life on Earth was a single-celled microbe that resembled bacteria. Cyanobacteria, once the most abundant family of species on Earth, use sunlight and carbon dioxide to produce energy through photosynthesis and release oxygen as waste. The increase in atmospheric oxygen triggered a series of major changes, such as a drop in global temperature, which geologists call the "Great Oxidation" and "Snow Earth" events.

About 2 billion years ago (or earlier), a form of life known as "eukaryotes" emerged. Compared with the early simple microorganisms without nuclei, this new life has more complex cells, and its main feature is the evolution of nuclei that can wrap DNA. This creature was the original ancestor of all present-day multicellular life.

Although the earth is 4.55 billion years old, it was not until 15 to 1.8 billion years ago that the first verifiable supercontinent, the Columbia supercontinent, appeared on the earth. Scientists confirmed its existence based on paleomagnetic evidence. What the earth looked like before this, at present (2024) can only be guessed.

About 1.2 billion years ago, another milestone occurred in biological history: some eukaryotes evolved new "sexual reproduction" mechanisms to create new life. But this new way of "birth" will also require a small price: the participating individuals will sooner or later "die".

About 1.5 billion years ago, the Columbia supercontinent disintegrated. 0.4 billion years later, its fragments began to reassemble to form another supercontinent called Rodinia. At that time, most of the earth's land mass belonged to this supercontinent. Rodinia would also disintegrate, but its disintegration would subversively change the biosphere and trigger a major leap in the form of life on Earth.

Like prokaryotes, some originally completely independent single-celled eukaryotes also like to live in groups. In some clusters, molecular mechanisms that linked the original independent cells together appeared, and a division of labor was formed between different cells; so about 1 billion years ago, a revolution broke out again in the history of life evolution, and complex multicellular organisms were born.

After the disintegration of the Rodinia supercontinent, the earth's constant temperature system had problems, and it experienced several severe ice ages intermittently during the 0.15 billion years. When the climate finally warmed up, an unprecedented number of wonderful species appeared in the ocean, completely changing the world once dominated by microorganisms, and ushering in a great change in the biological world. This group of mollusks is known collectively as the "Ediacaran Biota".

About 0.542 billion years ago, the animal kingdom suddenly developed extremely colorful and surprising forms. This important event is the image of paleontologists named: the Cambrian explosion of life. It marks a simple life form that lasted more than 3 billion years and has since been completely changed.

From the perspective of human beings, chordates are the most "advanced" group in the biological world and the "most successful" class of animals. Their common characteristics are: in the whole process of its development or a certain period, chordate has a notochord, dorsal neural tube and branchial cleft. Even the "spirit of all things" human beings, is no exception, everyone in the embryonic stage, will grow "gill cleft" on both sides of the neck, this is from the memory of the ancient ocean, we used to be "little mermaid".

The "Caledonian orogeny" began approximately from the Cambrian and reached its peak in the Ordovician. It lasted for a long time, and later experienced the Devonian and was active until the Carboniferous. The orogenic movement expanded the land area, prepared a new stage for the biosphere, and opened a new era.

The Ordovician Radiation may be the largest species expansion in geological history, far exceeding the Cambrian explosion before it. In this biodiversity differentiation that lasted almost the entire Ordovician, various species have been greatly enriched and developed in the order, family, and genus levels.

From the beginning of the Cambrian period, the sea became bustling and various exotic species appeared and died out in large numbers, but the vast land remained a forbidden zone for life. It was very difficult to live on land, but the brave plants changed the world at that time.

The Ordovician extinction event occurred about 0.445 billion years ago, and was the second most destructive of the five mass extinctions in Earth's history, causing the extinction of about 85% of species.

The emergence and rise of jaw species is one of the most critical leaps in the evolution history of vertebrates "from fish to man. For mammals, including humans, many important organs and body configurations can be traced back to the earliest jawed evolution.

In the short Silurian period, in addition to the appearance of the jaw, another major event is the evolution of the "vascular system" of plants ". Plants finally have the ability to transport nutrients, will become more and more tall, but also completely out of the aquatic environment.

In the Silurian, invertebrates set foot on land and began to thrive on the land. Among these pioneers were the ancestors of polypods such as centipedes and millipedes, as well as the ancestors of spiders and scorpions.

The plant evolved real roots and leaves, and grew larger and larger, resulting in the first ever vast forest, an extremely important period for life on land.

After plants and arthropods successively landed on land, a kind of teleost fish called "meat fin fish" also left the first footprints of vertebrates on land. This is a moment worth remembering. Our arms, wings or legs are actually "fleshy fins" transformed by years ".

In the late Devonian, the second major extinction event in biological history occurred, also known as the "late Devonian extinction". It is estimated that at least 75% of the species died out.

Following the "Caledonian Movement", the sea and mountains changed roles again, and more intense geological activity occurred above the earth's crust. Scientists call this movement the "Hercynian Movement". The land area has expanded unprecedentedly, and the earth has seen half land and half ocean.

In the Carboniferous period, another important turning point appeared in the evolution of vertebrates: the early tetrapods transitioned from water to land, and "amniotes" that were completely adapted to land appeared ". Later, these species differentiated into "lizard" and "monoporous". The former is the ancestor of future reptiles and birds, and the latter is the ancestor of future mammals.

In the late Carboniferous period, the vast rainforest suddenly shrank in thousands of years, the once common scales and reeds disappeared, and most of the green surrounding the equator was lost. The catastrophe, known as the "Late Carboniferous Rainforest Collapse", saw the extinction of giant arthropod species and heavy damage to amphibians, turning the subsequent "Permian" into a stage for amniotic animals.

With the collapse of the rainforest, giant arthropods and amphibians have lost their former glory, and their ecological niches have been replaced by former prey, amniotes that have escaped and evolved rapidly. As a result, the biosphere has changed its form again, represented by species such as the famous "Kiosaurus" and "Heterodentate.

As the offspring of meat-finned fish, after amniotic animals adapted to the terrestrial environment, their offspring species diverged again, and two important branches were born, namely "lizard" and "synovial arch". Among them, a separate category, "mammal-like reptiles", emerged in the evolution of the Syringa, which was also the ancient ancestor of all later mammals.

At the end of the Permian, the largest mass extinction in Earth's history occurred, with an estimated 96% of species lost forever, and it took 30 million years for ecosystems to fully recover. Most scholars believe that large-scale volcanic activity was the initiator of this huge disaster.

In the early Triassic, the coastline became very short due to the existence of supercontinents, and a group of animals were forced to adapt to both land and shallow sea life. They were the ancestors of ichthyosaurs. Over tens of millions of years, the original terrestrial species evolved streamlined bodies and eventually returned to the ocean.

The emergence of dinosaurs began 0.24 billion -0.23 billion years ago. "Herrerosaurus" and "Starraptor" are the earliest members of the dinosaur family and evolved from ancestral species similar in size to modern domestic cats. At first, dinosaurs did not dominate. For 30 million long years, they were nothing more than the dessert of predators such as fake crocodiles or super salamanders.

About 0.235 billion years ago, there was volcanic activity that lasted for about 5 million years near the present-day Alaska in the United States; the global temperature soared and the ocean evaporated, triggering a rainy season that lasted about 2 million years, the famous "Carnian flood event". Many species went extinct, but the surviving gymnosperms and dinosaurs benefited.

Based on fossil evidence, it is estimated that mammals originated in the late Triassic period about 0.22 billion years ago. They are a small group of warm-blooded animals that mainly feed on insects. They lived in the jungle with early dinosaurs. Some species can live as long as 14 years.

At the end of the Triassic, the United ancient land began to disintegrate, and another mass extinction spread to the entire biosphere, that is, the Triassic-Jurassic extinction event. The effects of the event spread to land and sea, and at least 50% of the species were lost forever. The surviving dinosaur family rises to dominate the animal kingdom.

During the Jurassic period, the most fascinating insects appeared. They were the butterflies that babbling children would draw when they picked up their pens. Butterflies and moths belong to the order Lepidoptera. The earliest known species in this order is the ancient scale moth, about 0.19 billion years ago.

In the early Jurassic period, about 0.183 billion years ago, with the disintegration of the United Continent, there was a period of extreme heat spanning hundreds of thousands of years, that is, the "Thor stage extreme heat event". High temperature and hypoxia caused the extinction of a large number of marine life, but also reduced the abundance and diversity of terrestrial ecosystems.

After the extinction at the end of the Triassic, the geological age was switched to the Jurassic period. The surviving dinosaurs occupied the main position among terrestrial animals. Their species and numbers became more and more, and the dinosaur age officially came. We picked the amazing "allosaurus" and saw it as the start of this long, more than 0.1 billion-year era.

Archaeopteryx is a transitional species between dinosaurs and birds. They have the main characteristics of both. They may be the first species to transform from land to birds. This change, which has a great impact on the present, occurred about 0.15 billion years ago in the late Jurassic period.

The extant mammals include three subclasses, namely, the original beast, the latter beast, and the true beast. The latter beast is a marsupial, and the real beast, including human beings, accounts for 95% of the existing mammals, which is obviously the dominant species in today's biological world. True beasts belong to viviparous, with a true placenta, and the differentiation of the two occurred at the end of the Jurassic.

About 0.14 billion years ago, the first real flower in the world bloomed silently in an inconspicuous place. Small flowers open a colorful world, after all, in the dark universe, a planet wearing flowers, how different!

Now that there are flowers, but for whom do they bloom? The answer will obviously include insects, especially a class of insects that co-evolved with flowers, including the earliest "bees", which were the "ancient bees" that lived on Gondwana in the early Cretaceous ".

The "disintegration of the supercontinent" and the "rise of angiosperms" together created the climax of the radiation evolution of species during the Cretaceous period: plants changed forms, land and sky were occupied by dinosaurs and pterosaurs, respectively; and the last top predators of the Mesozoic era appeared in the ocean, which were the Canglong.

In the middle of the Cretaceous, the dinosaur family gave birth to the largest terrestrial species in known history, the "Argentinosaurus". This is a "sauropod" dinosaur with a body length of up to 45 meters and a weight of up to 100 tons, equivalent to 10 elephants.

"Tyrannosaurus Rex", also known as "King Tyrannosaurus Rex", is a well-deserved "star" in many film and television works ". They are up to 13 meters long, about 5 meters high and weigh up to 16 tons. Tyrannosaurus rex is one of the largest carnivores ever seen on land. It is not only the pinnacle of the dinosaur era, but also the last song before the end.

All beauty will eventually be dissipated by beauty, and there will be an end when there is an opening. Even if the world of dinosaurs is at its peak, there will be no reason for any change for a long time. But a lost asteroid suddenly and unusually cruel, for the world to draw an end.

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This website is entitled to serve as a valuable reference. If you happen to see this text and have a professional background and sharing intention, the author also urges you to help with this knowledge puzzle. In fact, everything can be placed in the context of history to be examined, and to establish relations with other things. And this connection is vital, even more important than the things and knowledge themselves!