The universe is really massive and beautiful. There are many galaxies within the universe and we belong to one of the beautiful galaxies, The Milkyway Galaxy.
The earth we live in was merely a part of the giant gas cloud called the nebula, around 4.6 billion years ago. The mass of the nebula caused it to crush all the gassy material present in it into a plane, even as it was constantly spinning. This disc of material is called the protoplanetary disc.
Over a period of a hundred thousand years after the collapse, the Sun was formed at the very center of the protoplanetary disc, with the rest of the nebular gas swirling around it. These gases began to clump at various spots.
These clumped gases under constant collisions formed miniature planets called the planetesimals. These planetesimals grew bigger with time and formed true planets within 1,00,000 years after the formation of the Sun.
The gas giants, Jupiter and Saturn, and the ice giants, Uranus and Neptune, formed faster than the rest four terrestrial planets, Mercury, Venus, Earth, and Mars.
Even though the earth was formed, it didn’t look the way it looks now. It was a hot planet with melted rocks. The earth was filled with volcanoes all over the place, filled with lava and gas. But with time the earth started cooling down. The rocks filled with ice and gas started melting to form the sea.
The top layer of the earth cooled down to form the crust. But still, the core of the earth consists of molten lava. Slowly, plants and other life forms started growing on our very earth. The story of how plants and other life forms evolved is a very interesting story for some other day.
First Life
According to scientists, life on earth was first observed 3.8 billion years ago. Earth consisted of bacteria and archaea. Even though the origin is still not certain, with the upcoming technology we never know what we may discover in the coming future.
During this period, the earth’s atmosphere wasn’t feasible for human life to exist since it consisted of methane. But “the great oxidation event” took place, where the cyanobacteria through photosynthesis started to release oxygen.
This released oxygen formed the atmosphere. Dissolved oxygen started reacting with the iron present in the sea, forming rust, which sunk to the seafloor. There are speculations still being raised by scientists about the timeline and whether or not this was the work of cyanobacteria.
Around 2.3 billion years ago, the whole earth became frozen for the first time and was called ‘snowball earth’. This was caused by reduced volcanic activities on earth. When the ice melted, it released higher amounts of oxygen into the atmosphere.
The whole history of the earth is quite interesting and there are more to come. So, hang on and continue reading what happens next on our beloved earth.
Two billion years ago, scientists claim that the first eukaryotic cell (cells with organelles) was formed. These cells had one major organelle named nucleus, which built the genetic material of the cell. These eukaryotic cells started their symbiotic relationship with the first beings on earth, bacteria.
This relationship eventually leads to the division of eukaryotic cells into three categories 1.5 billion years ago. They were the ancestors of modern plants, fungi, and animals which split into different lineages and evolved later on.
Then comes the entry of the first multicellular organism 900 million years ago. Just like many other cases, scientists are still unable to put a finger on how it happened, but they do believe that modern choanoflagellates are the most closely related to multicellular organisms.
The multicellular organisms evolved and went through their first splitting 800 million years ago. They split to form sponges and Eumetazoa. After 20 million years, a small group called the placozoa breaks away from the Eumetazoa. It has been said that placozoa may be the last common ancestor of all the ancestors.
Once again earth freezes around 770 million years ago. 730 million years ago to 565 million years ago, it is believed that the animal kingdom divided into various phylum. But it was 540 million years ago when the first chordate came into existence.
Even though the earth was formed, it didn’t look the way it looks now. It was a hot planet with melted rocks. The earth was filled with volcanoes all over the place, filled with lava and gas. But with time the earth started cooling down. The rocks filled with ice and gas started melting to form the sea.
The top layer of the earth cooled down to form the crust. But still, the core of the earth consists of molten lava. Slowly, plants and other life forms started growing on our very earth. The story of how plants and other life forms evolved is a very interesting story for some other day.
First Life
According to scientists, life on earth was first observed 3.8 billion years ago. Earth consisted of bacteria and archaea. Even though the origin is still not certain, with the upcoming technology we never know what we may discover in the coming future.
During this period, the earth’s atmosphere wasn’t feasible for human life to exist since it consisted of methane. But “the great oxidation event” took place, where the cyanobacteria through photosynthesis started to release oxygen.
This released oxygen formed the atmosphere. Dissolved oxygen started reacting with the iron present in the sea, forming rust, which sunk to the seafloor. There are speculations still being raised by scientists about the timeline and whether or not this was the work of cyanobacteria.
Around 2.3 billion years ago, the whole earth became frozen for the first time and was called ‘snowball earth’. This was caused by reduced volcanic activities on earth. When the ice melted, it released higher amounts of oxygen into the atmosphere.
The whole history of the earth is quite interesting and there are more to come. So, hang on and continue reading what happens next on our beloved earth.
Two billion years ago, scientists claim that the first eukaryotic cell (cells with organelles) was formed. These cells had one major organelle named nucleus, which built the genetic material of the cell. These eukaryotic cells started their symbiotic relationship with the first beings on earth, bacteria.
This relationship eventually leads to the division of eukaryotic cells into three categories 1.5 billion years ago. They were the ancestors of modern plants, fungi, and animals which split into different lineages and evolved later on.
Then comes the entry of the first multicellular organism 900 million years ago. Just like many other cases, scientists are still unable to put a finger on how it happened, but they do believe that modern choanoflagellates are the most closely related to multicellular organisms.
The multicellular organisms evolved and went through their first splitting 800 million years ago. They split to form sponges and Eumetazoa. After 20 million years, a small group called the placozoa breaks away from the Eumetazoa. It has been said that placozoa may be the last common ancestor of all the ancestors.
Once again earth freezes around 770 million years ago. 730 million years ago to 565 million years ago, it is believed that the animal kingdom divided into various phylum. But it was 540 million years ago when the first chordate came into existence.
Human Existence
Now you must be feeling restless on knowing when did the humans come into being. Chordates have formed, but what now? Chordates were just an introduction to the world of vertebrates. The first and true vertebrate was formed 530 million years ago.
This follows the formation of all the other classes: Pisces, Amphibia, Reptilia, Aves, and Mammalia. These classes are inter-related, yet very vast. These evolutions took place between 530 million years ago to 7 million years ago.
Not only the animal kingdom but plant kingdom also evolved during this time. The birth of dinosaurs to grasses and what not. Many of the life forms took birth and went extinct during this timeline. But until this time, humans did not evolve.
Six million years ago is the time when humans diverged with their closest relative: chimpanzees and bonobos. The first-ever hominin (a term referred to humans in early timelines) was the Sahelanthropus. It portrayed the most important hominin trait: upright walking.
Around 5.2 to 5.8 million years ago, the Ardipithecus Kadabba came into existence. The fossils of these beings were found in Ethiopia and lived in a mixed habitat of grasslands and woodlands.
The evolution of the hominins started picking up pace. The different hominins after evolution were: Ardipithecus ramidus (4.4 million years ago), Australopithecus anamnesis (3.9-4.2 million years ago), Australopithecus afarensis (2.95-3.85 million years ago), Kenyanthropus Platyopus (3.2-3.5 million years ago).
Not only the animal kingdom but plant kingdom also evolved during this time. The birth of dinosaurs to grasses and what not. Many of the life forms took birth and went extinct during this timeline. But until this time, humans did not evolve.
Six million years ago is the time when humans diverged with their closest relative: chimpanzees and bonobos. The first-ever hominin (a term referred to humans in early timelines) was the Sahelanthropus. It portrayed the most important hominin trait: upright walking.
Around 5.2 to 5.8 million years ago, the Ardipithecus Kadabba came into existence. The fossils of these beings were found in Ethiopia and lived in a mixed habitat of grasslands and woodlands.
The evolution of the hominins started picking up pace. The different hominins after evolution were: Ardipithecus ramidus (4.4 million years ago), Australopithecus anamnesis (3.9-4.2 million years ago), Australopithecus afarensis (2.95-3.85 million years ago), Kenyanthropus Platyopus (3.2-3.5 million years ago).
Australopithecus africanus (2.1-3.3 million years ago), Paranthropus Aethiopicus (1.2-2.3 million years ago), Paranthropus Boisei (1.2-2.3 million years ago), Homo habilis (1.4-2.33 million years ago), Homo Rudolfensis (1.8-1.9 million years ago), Homo ergaster (1.3-1.8 million years ago), Homo Erectus (2,00,000-1.89 million years ago).
Homo heidelbergensis (2,00,000-7,00,000 years ago) and Homo rhodesiensis (1,25,000-4,00,000 years ago).
These were the various evolutionary forms that humans went through. But the most important and the one that everyone knows about is the Homo Neanderthalensis (40,000-4,00,000 years ago) or, famously known as the Neanderthals are the closest extinct human relative.
These were the various evolutionary forms that humans went through. But the most important and the one that everyone knows about is the Homo Neanderthalensis (40,000-4,00,000 years ago) or, famously known as the Neanderthals are the closest extinct human relative.
They were shorter but bulkier than modern human beings. They weren’t much different than us. They did all the activities that we do, like hunting, wearing clothes, burying the dead, etc.
The scientists haven’t found an explanation on how the Neanderthals got wiped out, yet. They built various theories like competition with the homo sapiens, climatic changes, or both. They were as smart as homo sapiens- but they were still fragile enough to get wiped out. Nevertheless, each of us consists of a part of Neanderthals DNA in us.
And last but not the least, we came into existence- Homo sapiens. The formation of earth was a really long process. From being a gas cloud to a living planet, was a long journey. The earth is still evolving and so are we. The roller coaster ride hasn’t hit the stop button yet, so fasten your seatbelts even tighter and keep yourself updated on what the earth has yet to offer us.
Written by - Farheen Firoz
The scientists haven’t found an explanation on how the Neanderthals got wiped out, yet. They built various theories like competition with the homo sapiens, climatic changes, or both. They were as smart as homo sapiens- but they were still fragile enough to get wiped out. Nevertheless, each of us consists of a part of Neanderthals DNA in us.
And last but not the least, we came into existence- Homo sapiens. The formation of earth was a really long process. From being a gas cloud to a living planet, was a long journey. The earth is still evolving and so are we. The roller coaster ride hasn’t hit the stop button yet, so fasten your seatbelts even tighter and keep yourself updated on what the earth has yet to offer us.
Written by - Farheen Firoz
Edited by - Rudransh Khurana
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