Today there are at least 11,000 bird species. But with such a close relationship to the extinct dinosaurs, why did birds survive? The answer probably lies in a combination of things: their small size, the fact they can eat a lot of different foods and their ability to fly.
The gradual evolutionary change - from fast-running, ground-dwelling bipedal theropods to small, winged flying birds - probably started about 160 million years ago. It was possibly due to a move by some small theropods into trees in search of either food or protection.
Quaillike creatures were the only birds to survive the dinosaur-killing asteroid impact.
"So the hypothesis that came out of this was the animals that survived the extinction preferentially survived because they were able to dig to get underground, survive that immediate impact period and the fires, the nuclear winter, and just hunker down for a bit."
Birds Survived Mass Extinction That Wiped Out Dinosaurs Because Of Their Larger Brains. Summary: The Cretaceous--Tertiary mass extinction 65 million years ago may have wiped out the dinosaurs, but those that survived -- the ancestors of today's birds -- may have done so because of their bird brains.
The exact nature of this catastrophic event is still open to scientific debate. Evidence suggests an asteroid impact was the main culprit. Volcanic eruptions that caused large-scale climate change may also have been involved, together with more gradual changes to Earth's climate that happened over millions of years.
Birds: Birds are the only dinosaurs to survive the mass extinction event 65 million years ago. Frogs & Salamanders: These seemingly delicate amphibians survived the extinction that wiped out larger animals. Lizards: These reptiles, distant relatives of dinosaurs, survived the extinction.
There are two main reasons. First, crocodiles can live for a very long time without food. Second, they lived in places that were the least affected when the asteroid hit Earth.
What scientists have been trying to figure out, however, is why mammals survived while the dinosaurs perished. According to Penn State researcher Russ Graham, the lifestyles of mammals gave them an advantage when the asteroid struck the area that is today's Yucatan peninsula about 65 million years ago.
But scientists say a handful of surviving snake species were able to thrive in a post-apocalyptic world by hiding underground and going long periods without food. The resilient reptiles then spread out across the globe, evolving into the 3,000 or more species known today.
Tardigrades have been around a long time.
Fossils date their existence on Earth to more than 500 million years ago. This means tardigrades have survived the planet's last five mass extinction events.
Hoatzins are the only living representatives of one of the most ancient lineages of birds, with origins about 64 million years ago. Young hoatzin have two claws on the bones that support their flight feathers—that is, on their hands.
This is because animals today have a very different evolutionary past to dinosaurs. They evolved to have features that help them survive in today's world, rather than a prehistoric one. And these features limit the ways they can evolve in the future.
In fact, birds are commonly thought to be the only animals around today that are direct descendants of dinosaurs. So next time you visit a farm, take a moment to think about it. All those squawking chickens are actually the closest living relatives of the most incredible predator the world has ever known!
While all birds are descended from dinosaurs, the mysterious cassowary is thought to be more similar to ancient dinosaurs than most other birds. Large bodied with fierce claws, these flightless birds also have casques, a helmet-like structure atop the head, which many dinosaurs are believed to have had.
Fossil studies have long suggested modern birds were descended from T. rex, based in similarities in their skeletons. Now, bits of protein obtained from connective tissues in a T. rex fossil shows a relationship to birds including chickens and ostriches, according to a report in Friday's edition of the journal Science.
For approximately 120 million years—from the Carboniferous to the middle Triassic periods—terrestrial life was dominated by the pelycosaurs, archosaurs, and therapsids (the so-called "mammal-like reptiles") that preceded the dinosaurs.
Originally Answered: How did the cavemen survive the asteroid bit the dinosaur didn't survive? Simply because they were separated by about 63 to 65 million years (depending on your definition of caveman).
Mammals did the opposite: with their small body sizes, they could exploit ecological niches that the bigger dinosaurs couldn't access. Having attained a competitive edge in those habitats, they effectively prevented T. rex, Triceratops and kin from becoming small.
The finding published in the journal PLOS Biology also suggested that some shark species were in decline before the asteroid hit but began to thrive after it due to their ability to repair DNA damage.
Humans survived when the Sun was blocked out
There is evidence that a kilometer long asteroid crashed into Southeast Asia around 800,000 years ago — and our ancestors had survived it. The asteroid did impact human evolution and blocked out the Sun for years with the dust it threw up. Yet, humanity was not wiped out.
The last Age of the Dinosaurs is known as the Maastrichtian, which spanned around six million years and ended with the catastrophic impact.
Dinosaurs went extinct about 65 million years ago (at the end of the Cretaceous Period), after living on Earth for about 165 million years.
He and all of the other researchers, however, suspect that more recent dinosaurs even closer to the K-T boundary will be found in the future. For now, however, the 65-million-year-old Triceratops is the world's last known surviving dinosaur.