We, Homo Sapiens, are mammals, animals, primates, and Big Apes. And we represent an intelligent life on our planet. That specific evolution path from first mammals to humans within the class of Mammalia would not be possible without an interference of extraterrestrial forces in evolution about 66 million years ago.
What Is Your Guess on The Winner – Dinosaurs? Raccoons?
Dinosaurs emerged on our planet around 247 – 240 million years ago. Mammals first appeared about 225 million years ago. Mammals coexisted with dinosaurs for around 160 million years until dinosaurs were wiped out at last mass extinction.
Who ruled the Earth in over 160 million years – dinosaurs or mammals? We all know the answer – dinosaurs were a big winner of evolution since their appearance 240 million years ago.
What about mammals? Did the biological evolution managed to move mammals towards an intelligent life during 225 million years? Or even towards beings, who rule the Earth? Not much. Mammals were really small and insignificant all that time. The biggest mammals were Repenomamus, which weighed 12–14 kilograms, and the raccoon-sized Vintana weighed 9 kg. Compare it with the estimated weight of the top dinosaur, Titanosauria, of around 70 tons.
We have a piece of evidence now that Repenomamus mammal ate juvenal dinosaurs sometimes. Yet, in who-eat-whom battle, huge 70-tons’ dinosaurs prevailed over 12-kg-or-less mammals. During 160 million years of coexistence of mammals with dinosaurs, the former did not diversify much and did not grow much in size.
No Pathway to Bigger Brain
Here, on Earth, we associate an intelligence in biological beings with a brain. How exactly to associate? That is not an easy question to answer. It is a part of the ongoing debate among scientists.
Some scholars look into the weight of the brain. The average human brain weighs 1400 g. The raccoon brain weighs 39 g. By that measure, humans are more than 35 times smarter than raccoons.
One other way is to measure the number of neurons in the cerebral cortex in the brain. There are about 16 billion cortical neurons in the human brain, and about 438 million in a raccoon’s brain. In this case, raccoons are more than 36 times dumber than humans.
The Rise of Insignificant Actors in Evolutionary Desert
About 66 million years ago there was the last mass extinction before the first humans appeared on Earth. As usual, evolutionary losers were impacted as it happens all the time during background biological evolution. During the mass extinction many evolutionary winners lose it all as well. The dominant beings, dinosaurs, just disappeared from the face of Earth. That changed an evolutionary landscape over a whole planet and opened evolutionary niches for small creatures.
Within 700,000 years of the mass extinction mammals’ “body mass had become 100 times bigger than the mammals living immediately after the mass extinction”.
At the time of dinosaurs, there were eight mammals’ orders. As of now, scholars know 29 orders in Mammalia class. 21 new orders were branched off in just 20 million years after the last mass extinction. That is very fast in geological terms. Eventually evolutionary march of mammals led to us, humans.
Out-of-A-Line Cause of Mass Extinction
The previous mass extinctions were triggered by some events, which were internal to our planet. That is the current understanding by the scientists’ community, However, the extinction, which happen 66 million years ago, was caused by an extraterrestrial force. That extinction is called Cretaceous–Tertiary (K–T) extinction.
The primary cause was an Earth collision with an asteroid. The diameter of that asteroid was about 10 km.
That collision caused so-called an “impact winter” on a whole planet for several years. During the “impact winter,” a dust cloud blocked sunlight for a few years. That, in turn, prevented photosynthesis on the planet. There were other global consequences. An original hypothesis about this event was proposed by scientists Luis and Walter Alvarez. The Chicxulub crater, created by this collision, was found in Mexico. The crater diameter is 180 km.
Big Kill at A Right Time
An asteroid collision at Chicxulub happened 66,038,000 years ago, plus or minus 11,000 years. We know that K–T extinction, which wiped out dinosaurs and freed up evolutionary niches for mammals, happen after that collision.
How often similar collisions with causing-mass-extinction asteroids could happen on Earth? Recently NASA made the proper calculations. The probability of up-to-10-km-wide asteroid hitting Earth is around 0.000001% per year.
That means it is highly probable to get such a hit in 100 million years. What is important that this is a calculated probability, but not certainty. As for now, scientists have evidence of only one such collision during the last 500 million years.
Let us imagine what may happen if that collision occurs just one hundred thousand or one million years later, but all other evolutionary events after the collision will be the same as they were in reality. Well, in that scenario Homo Sapiens’ intelligence will not be on Earth during the Holocene geological period.
Holocene was and is a blessing time for Homo Sapiens, who were able to domesticate plants and animals and build complex societies during the Holocene. Without Holocene, humans, probably, will still be just one of many insignificant animals on the planet. And there would be no written history of humanity.
In other words, an extraterrestrial force helped to kill dinosaurs exactly at the right time for human intelligence to thrive. Of course, there was nobody behind this asteroid waiting to throw it to Earth at the right
moment. Yet, it tells us a lot about randomness in this Universe.
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