How Was Earth Millions of Years Ago?
Long before humans developed the selfie stick and the ability to talk to artificial intelligence, our humble beginnings were as a bunch of chemical compounds in what’s referred to as the “Primordial Soup”. This was about 3.7 billion years ago. That soup led to all life on Earth, starting with single-cell organisms. These organisms turned into multicellular organisms about 900 million years ago, and over a period of a few more hundred million years, Jellyfish and other sea creatures arrived on the scene.
Things got interesting here on Earth during what’s known as the Cambrian Explosion 535 million years ago when multiple complex life forms sprang to life. Fast forward about 138 million years and four-legged creatures called tetrapods crawled out of the shallow water and found land.
The very beginning is thought to have happened about 4.54 billion years ago. It all started with a big bang and an exploding star (supernova), which created a vast cloud of gases and dust. As you can imagine, that explosion was rather hot, and the dust mixture started cooking and formed into lumps. The main lump was so hot and dense in the middle, that it started creating nuclear fires. This was the beginning of what we call the Sun. Around it in the cloud were other clumps, and these formed into a disc. This very hot leftover material cooled down and formed all the planets, including ours, Earth.
The planets pretty much arranged themselves in orbit and Earth ended up being the third planet from the sun. The moon formed when one of the big chunks in that cloud, called a planetesimal, hit the Earth. This threw some of the Earth’s crust into space and that’s the grey rock we’ve been staring at all our lives when the Sun shines a light on it. The crash knocked the Earth so hard it tilted at 23.5 degrees, and that’s the reason we have seasons. Our ever-loving Sun, scientists agree, will eventually destroy the Earth. It gets 10 percent hotter every billion years, and in the end, it’ll boil Earth’s oceans and grill the rest.
The Cambrian explosion resulted in many of the early complex lifeforms. We should mention that the Earth wasn’t always split into continents, rather there was a supercontinent we call Pangaea that eventually split apart. Only one ocean called the Panthalassa surrounded this supercontinent.
Back to the animals.
The fossil record shows that evolution was a slow business, and that’s why some scientists refer to a certain period as “The Boring Billion”. Not much happened. Then evolution went into overdrive when organisms stopped just splitting into two parts and started mating.
This was about 1.2 billion years ago in the Proterozoic Eon. The Earth went through periods of warming and freezing, and anything on it had to endure those changes or die. Some life forms would survive and others would perish. During the end of the Ordovician period, around 85% of all life that had been flourishing, most of it in the sea, became extinct during an ice age. Much more devastating extinction would take place, such as the Permian extinction that killed about 96 percent of marine species and land animals. This brings us to the dinosaurs, the creatures that started wondering around Earth about 230 million years ago.
There were thought to be about 700 different species of dinosaurs on the planet over a period of about 160 million years. For all you budding time-travelers out there, one thing you need to know is that if you went back to try and live with these beasts is that if they didn’t kill you, the atmosphere probably would.
In fact, humans couldn’t have lived on Earth most of the time Earth has been around. Prior to the dino-days, there was very little oxygen, and certainly not enough for us. The nitrogen levels and greenhouse gases would suffocate us immediately. At other times there was lots of oxygen, about 35 percent at the most compared to today’s 20.95 percent. Some sources believe we could cope with that, others say we’d die. There’d be lots of fires around, too, with all that oxygen. But imagine, you had a fire-resistant space-suit or adaptive lungs – after all, you can time-travel, so you can probably make a really good pair of super-lungs.
Let’s say you came across a Diplodocus or Brachiosaurus.
These would look pretty scary as they were thought to weigh 25-50 tons (22,679 kilos – 45,359 kilos). The T-Rex was about 10 tons or just over 9,000 kilos. That’s slightly heavier than a very big African elephant. What might be scarier is the thought of giant bugs. Maybe the biggest of them all was the giant sea scorpion, which was about 2.4 meters in length.
In the air, the largest ever bird thought to have existed is the ‘Argentavis magnificens’, which had a wingspan of more than 20 feet (6 meters) and weighed about 240 pounds (108 kilos). Its diet consisted of animals bigger than humans.
Perhaps a more ignoble way to lose a fight would be with a giant prehistoric rodent. While many animal sizes during pre-history are estimates due to no fossils ever being found, scientists agree there were some pretty scary cuddly characters hanging around on Earth for a while.
Well after the dinosaurs were gone, a one-ton (907 kilos) rodent was said to roam around parts of South America. That was around 2-4 million years ago.
The rodent, known as the Josephoartigasia monesi, was said to have the biting power three times that of today’s tigers. Grazing animals had by then been around a long time. It’s thought that the Earth got a lot greener about 40 million years ago when grass suddenly started popping up all over the place. In time, animals started to graze, and by then all the dinosaurs had been wiped out by perhaps a massive asteroid hit. After this was a barren period and the Earth was quite swampy. Here reptiles ruled, with 50 foot (15.2 meters) snakes and 40 foot (12.1 meters) crocodiles enjoying the after-strike climate.
For the next few million years, primates would rise, including the first simians. Splits took place between these simians with apes, gibbons, orangutans, gorillas, and chimpanzees all entering the race for survival.
One thing you might be wondering after listening to how so many animals went extinct is how did some mammals or fish survive and others didn’t.
Why did a small amount of land mammals survive when dinosaurs met their fate?
According to one evolution specialist and paleontologist, science just doesn’t know, and experts are still perplexed about the issue. After the dinosaurs had gone – with some dinosaur birds surviving – the Earth was still home to turtles, frogs, lizards and as you know, crocodiles and snakes and placental mammals. In fact, because of the loss of predatory dinosaurs, mammals thrived in what is now known as The Age of Mammals. This is the reason we are all alive today. The first humans, homo sapiens, weren’t around back then. They only came about around 200,000 years ago.
The first of the homo genus is thought to have walked the Earth around 2-3 million years ago, with the upright kind, homo Erectus, dating back to 1.9 million years but being around until just 143,000 years ago. They made the fire, cooked food lived in groups, and took care of the weak. Just like most of us.
With all this mind, the question we might ask now is how will we evolve in the future? If there is another extinction: an asteroid hit, global warming, nuclear destruction, super-volcano eruption, what will survive and how will it survive? Most scientists agree that genetic modification will come before that. Only recently in the U.S. was an embryo successfully modified to prevent the onset of heart disease. The embryo was in a test lab and not implanted in a womb, but it’s likely this will become the norm as we go on. We are also veering closer to becoming part-machine, a cyborg, which could change what we essentially are.
As for more natural evolution, one scientist speaking to National Geographic said, “Human beings are just going to have to learn to live with themselves as they are.” This is because he believes in Darwinian principles that adaptation only occurs when circumstances demand it and humans have no need to mutate. That said, most scientists agree that the Earth itself will change. The sea level will rise considerably in the next few thousand years. Some experts believe in 50,000 years we will enter another glacial period. After this, the landscape of the Earth will change.
At some point in the next 500,000 years, it’s thought an asteroid will do a lot of damage to that changing landscape. In a billion years Earth may have dried up, and just 100 quintillion years later our one blue planet will have been engulfed by its mother Sun.
What are your feelings about the future of mankind and Earth?