When an asteroid the size of 10 billion atomic bombs struck the Earth 66 million years ago, it set off a series of events that resulted in the extinction of 90% of all species.

Only a small number of birds survived, but this catastrophic event allowed for the evolution of humans.

The remaining mammals thrived, including the tiny proto-primate ancestors of modern humans.

To this end, The Conversation posed a series of questions and analyses.

The news site posits that highly-evolved raptors might be setting up camp on the moon if the asteroid hadn't hit and dinosaurs had lived.

Scientists studying dinosaurs might be learning about relativity or speculating about a possible world in which incredible things like mammals colonized the planet.

Philosophical Questions on Evolution and Dinosauroid Beings

Nicholas Longrich, a senior lecturer in paleontology and evolutionary biology at the University of Bath, continued with questions concerning the existence of humanity and if the race is only here by chance.

He also mentioned the possibility that intelligent tool users will inevitably evolve.

With an estimated 8 billion people, humans have altered half of the planet's land for agricultural purposes.

Dale Russell, a paleontologist, proposed a theory in the 1980s that a carnivorous dinosaur could develop into an intelligent being that uses tools.

This "dinosauroid" walked upright and had a large brain and also had opposable thumbs.

The study by Russell was published in the Canadian Journal of Earth Sciences.

Although the idea is not impossible, according to Longrich, it is unlikely.

An animal's biology determines the course of its evolution, just as the beginning determines the end.

Looking at Dinosaurs

Dinosaur carnivores frequently developed into enormous, ten-meter-tall, multi-ton predators.

Megalosaurids, allosaurids, carcharodontosaurids, neovenatorids, and finally tyrannosaurs evolved into enormous apex predators for 100 million years.

Over time, dinosaurs did occupy new niches. Small herbivores proliferated, and bird species expanded.

Later forms developed long legs, indicating a struggle for survival between quick-footed predators and their prey.

Dinosaurs appear to have led social lives that grew more complex over time.

They began to live in herds and developed complex horns for display and combat.

There isn't much evidence from the history of the dinosaurs' first 100 million years that they would have behaved very differently if the earth had not been struck by an asteroid.

Those enormous tyrannosaur-like predators and supergiant, long-necked herbivores could still exist.

According to Longrich, There is little evidence that the dinosaurs would have evolved into geniuses, even though their brains may have grown slightly larger.

Mammals are also unlikely to have replaced them because dinosaurs controlled their environments up until the time of the asteroid strike.

Now, Mammals...

Meanwhile, mammals faced different restrictions.

Supergiant herbivores and carnivores were not ever evolved in them. But they continually developed large brains.

Orcas, baleen whales, sperm whales, elephants, leopard seals, and apes have enormous brains that are nearly as big as human brains.

Few modern-day dinosaur descendants, including some crow and parrot species, have complex brains.

They can use tools, communicate, and count, but mammals with large brains and complex behaviors, such as apes, elephants, and dolphins, are what have evolved.

Read also: Dinosaur Fossil Found in Mississippi: Looks Like an Ostrich, Tall as a Giraffe

On Guaranteed Evolution for Mammals

Later, Longrich asserts that the extinction of the dinosaurs did not necessarily guarantee the evolution of mammals.

Endpoints may be constrained by starting points, but they are not always guaranteed.

The evolution of primates provides evidence that evolution was not inevitable.

For 7 million years, primates in Africa did develop into apes with big brains and modern humans.

Primate evolution, however, took very different routes elsewhere.

35 million years ago, monkeys simply continued to evolve and create new species, and at least three different times-55 million years ago, 50 million years ago, and 20 million years ago-primate species arrived in North America.

Despite this, they did not develop into a species that produces nuclear weapons and uses smartphones.

Instead, they became extinct for unknown reasons.

Longrich ended his article in The Conversation by saying that even after the dinosaurs vanished, evolution still required the right circumstances and luck because, for instance, primate evolution in Africa took a distinctive turn.

The evolution of apes, which are terrestrial, large-bodied, big-brained, tool-using primates, was influenced by the flora, fauna, and geography of Africa, PhysOrg reported.

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