What would dinosaurs look like today if they hadn’t gone extinct?

66 million years ago, an asteroid with the force of 10 billion atomic bombs crashed into Earth and changed the course of evolution.

The sky darkened and the plants stopped photosynthesizing. The plants withered and then the animals that fed on them died. The food chain collapsed and over 90% of all species disappeared. When the dust settled, all dinosaurs became extinct except for a handful of birds.

But this cataclysmic event, in turn, made human evolution possible. The rest of the mammals, including small primitive primates, thrived.

Let’s imagine that an asteroid flew past the Earth, and the dinosaurs were spared. Imagine highly developed birds of prey. Here, dinosaur relativist scientists discover or discuss a hypothetical world in which mammals incredibly dominated Earth.

This may sound like bad science fiction, but it raises some deep philosophical questions about evolution. Humanity is here by chance? Brain, tools, language and large social groups make us the dominant species on planet Earth. There are 8 billion sane people on seven continents. And there are more people by weight than all land animals.

What would dinosaurs look like today if they had never died out? https://t.co/14pjSJd3Oc

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And we changed half the land area to feed ourselves. It can be objected that beings like humans must have evolved.

And in the 1980s, paleontologist Dale Russell proposed a thought experiment in which a carnivorous dinosaur turned into a gadget user.

This is not impossible, but unlikely, since animal biology limits the direction of their evolution.

And if you drop out of college, you probably won’t become a neurosurgeon, lawyer, or rocket scientist at NASA. But you can be an artist, an actor, or an entrepreneur. The paths we walk in life open some doors and close others. This is true for evolution as well.

Pay attention to the sizes of dinosaurs. Starting with the Jurassic dinosaurs and sauropods, brontosaurs and their relatives evolved into 30-50-ton giants up to 30 meters long – ten times the weight of an elephant and the length of a blue whale.

This has occurred in several groups, including diplodosids, brachiosaurids, triasaurids, mammansaurids, and titanosaurids.

And this happened on different continents, at different times and in different climates, from deserts to tropical forests. But other dinosaurs that lived in these conditions did not become supergiants.

Carnivorous dinosaurs repeatedly evolved into huge predators, ten meters long and weighing several tons. Over the course of 100 million years, megalosaurs, allosaurs, carcharodontosaurus, neovenatorians, and finally tyrannosaurs evolved as giant apex predators.

And dinosaurs were pretty good at handling big bodies. Dinosaurs showed a slight tendency to increase in brain size over time. Jurassic dinosaurs such as Allosaurus, Stegosaurus and Brachiosaurus had small brains.

By the Late Cretaceous, 80 million years later, dinosaurs and platypuses had developed larger brains. But, despite its size, the brain of a Tyrannosaurus rex weighs only 400 grams. The brain of a Velociraptor weighed 15 grams. The average human brain weighs 1.3 kilograms.

Dinosaurs eventually entered new domains. Smaller herbivores have become more common, and birds have become more diverse. Long-legged forms appeared later, indicating a race between long-legged predators and their prey.

Dinosaurs seem to lead increasingly complex social lives. They began to live in packs and developed elaborate antlers for fighting and display. However, dinosaurs seem to basically repeat themselves, turning into giant herbivores and carnivores with small brains.

And nearly 100 million years of dinosaur history hints that they would have done something radically different if an asteroid had not intervened. And we probably still have those giant, long-necked herbivores and tyrannosaur-like carnivores.

They may have developed slightly larger brains, but there is little evidence that they turned into geniuses. It is also unlikely that it was displaced by mammals. Dinosaurs monopolized their habitats to the end, until an asteroid crashed.

Meanwhile, mammals had various limitations. Giant herbivores and carnivores never evolved. But they developed big brains again and again. Megaminds (bigger or larger than ours) have evolved in killer whales, sperm whales, baleen whales, elephants, leopard seals and monkeys.

Today, some descendants of dinosaurs—birds such as crows and parrots—have complex brains. They can use tools, speak and count. But it is mammals like monkeys, elephants and dolphins that have developed the largest brains and most complex behaviors.

And the evolutionary history of the great apes suggests that our evolution was not deterministic at all. When monkeys arrived in South America 35 million years ago, they evolved into other types of monkeys. Primates arrived in North America at least three times: 55 million years ago, 50 million years ago and 20 million years ago.

In Africa, and only in Africa, primate evolution has taken a unique direction. Something in the fauna, flora and geography of Africa influenced the evolution of great apes: terrestrial, large-bodied, large-brained, tool-using primates.

Even after the extinction of the dinosaurs, our evolution required the right mix of chance and luck.

The report was prepared by Nicholas R. Longrich, Senior Lecturer in Paleontology and Evolutionary Biology at the University of Bath.

Source: Science Alert