Explanation from: https://en.wikipedia.org/wiki/History_of_Earth#Cambrian_explosion
Early photosynthetic systems, such as those in green and purple sulfur and green and purple nonsulfur bacteria, are thought to have been anoxygenic, and used various other molecules as electron donors rather than water. Green and purple sulfur bacteria are thought to have used hydrogen and sulfur as electron donors. Green nonsulfur bacteria used various amino and other organic acids as an electron donor. Purple nonsulfur bacteria used a variety of nonspecific organic molecules. The use of these molecules is consistent with the geological evidence that Earth's early atmosphere was highly reducing at that time.
Fossils of what are thought to be filamentous photosynthetic organisms have been dated at 3.4 billion years old.
The main source of oxygen in the Earth's atmosphere derives from oxygenic photosynthesis, and its first appearance is sometimes referred to as the oxygen catastrophe. Geological evidence suggests that oxygenic photosynthesis, such as that in cyanobacteria, became important during the Paleoproterozoic era around 2 billion years ago. Modern photosynthesis in plants and most photosynthetic prokaryotes is oxygenic. Oxygenic photosynthesis uses water as an electron donor, which is oxidized to molecular oxygen (O2) in the photosynthetic reaction center.
The Great Oxygenation Event (GOE), also called the Oxygen Catastrophe, Oxygen Crisis, Oxygen Revolution, or Great Oxidation, was the biologically induced appearance of dioxygen (O2) in Earth's atmosphere. Although geological, isotopic, and chemical evidence suggest that this major environmental change happened around 2.3 billion years ago (2.3 Ga), the actual causes and the exact date of the event are very contested amongst the scientific community. It has been argued that current geochemical and biomarker evidence for the development of oxygenic photosynthesis before the Great Oxidation Event has been mostly inconclusive.
Oceanic cyanobacteria, having developed into multicellular forms more than 2.3 billion years ago (approximately 200 million years before the GOE), became the first microbes to produce oxygen by photosynthesis. Before the GOE, any free oxygen they produced was chemically captured by dissolved iron or organic matter. The GOE was the point when these oxygen sinks became saturated and could not capture all of the oxygen that was produced by cyanobacterial photosynthesis. After the GOE, the excess free oxygen started to accumulate in the atmosphere.
The increased production of oxygen set Earth's original atmosphere off balance. Free oxygen is toxic to obligate anaerobic organisms, and the rising concentrations may have wiped out most of the Earth's anaerobic inhabitants at the time. Cyanobacteria were therefore responsible for one of the most significant extinction events in Earth's history. Besides marine cyanobacteria, there is also evidence of cyanobacteria on land.
A spike in chromium contained in ancient rock deposits shows that these rocks, formed underwater, had accumulated chromium washed off from continental shelves by rivers. The researchers chose to focus on chromium because it is not easily dissolved and its release would have required the presence of a powerful acid. One such acid is sulphuric acid, that would have been created through bacterial reactions with pyrite. Though cyanobacteria are responsible for the GOE, they are not the only organisms capable of releasing oxygen. Research has shown that microbial mats of oxygen-producing microbes will produce a thin layer, one or two millimeters thick, of oxygenated water in an otherwise anoxic environment even under thick ice, and before oxygen started accumulating in the atmosphere, organisms living on these mats would already be adapted to being exposed to oxygen. Additionally, the free oxygen reacted with atmospheric methane, a greenhouse gas, greatly reducing its concentration and triggering the Huronian glaciation, possibly the longest snowball Earth episode in Earth's history.
Eventually, aerobic organisms evolved, consuming oxygen and bringing about an equilibrium in its availability. Free oxygen has been an important constituent of the atmosphere ever since.
How we see the same situation from different perspectives...
*_A Small Story_*
To hunt crocodiles, the pond was dried.
No crocodiles were found because they can live on land too.
But all the small fish died.
This story has nothing to do with Demonetisation.
*_The longer version of the small story_*
In another village the pond had really dirty water .. For years (about 60) despite having a huge pond poor farmers had to look upwards to the sky for water for their families ..the pond was never cleaned. The crocodiles were never hunted and no one cared if the fishes died . The water remained murky and could never be used for drinking. The entire village never grew to its potential. Then one day a man took upon himself the challange and decided to clean the water. Some people who used to sell water tankers to the villagers were not happy and they did every bit to make sure that the man would not succeed.. They threw back dirt in water.. They pulled out the dead fish and called it outcome of water cleaning act.. They blamed it on the guy who was cleaning the water..
While most saw what was happening some still went wayward..
These guys now said that they could still see the crocodile in the water.. They said hey.. The crocodiles are still there .. We can clearly see them. So whats changed
Now thats the moral of the story.. This was never about hunting the crocodile..
This was always about giving fresh water to the village and to make sure the crocs are visible.. So that if they need to be hunted they can be hunted
This long story has everything to do with demonetization and as for the man who wanted to clean the water ..
He's now planning other cleanups..
So.. in the end that's just how you look at it...🙂
During the Soviet dictatorship of Stalin, he (Stalin) came to one Politburo meeting with a live chicken. He started to pluck its feathers one by one off.
The chicken quacked in pain, blood oozing from its pores. It gave out heartbreaking cries but Stalin continued without remorse plucking feather after feather until the chicken was completely naked. After that, he threw the chicken on the ground and from his pockets, took out some chicken feed and started to throw it at the poor creature. It started eating and as he walked away, the chicken followed him and sat at his feet feeding from his hand.
Stalin then told members of his party leadership "This chicken represents the people, you must disempower them, brutalise them, beat them up and leave them. If you do this and then give them peanuts when they are in that helpless and desperate situation, they will blindly follow you for the rest of their life.They will think you are a hero forever. They will forget that, it is you who brought them to that situation in the first place."
Does this sound familiar?
Should not blame Appollo hospital. When you enter greams Road and turn towards Appollo hospital, there is a sign board 'One Way'. In spite of that many are admitted.😜
One day an aeroplane cleaner was cleaning the pilots' cockpit when he saw a book entitled "How to fly an aeroplane for beginners. Volume One".
He opened the first page which said, "To start the engine, press the red button.". He did so and the airplane engine started.
He was happy and opened the next page. "To set airplane moving press the blue button."
He did so and the aeroplane started moving at an amazing speed.
He wanted to fly so he opened the third page which read, "To let the aeroplane fly, please press the green button."
He did this and the plane started to fly.
He was excited!!!!!!
After 20 minutes of flying, he was satisfied and wanted to land so he decided to go to the fourth page.
He fainted after reading the instructions…….
The fourth page read, "To learn how to land, please purchase Volume Two at the nearest bookshop!!!!
Title of the book was
(The govt too is confused now as to how to land safely.)