It’s sometimes hard to imagine how the planet we call home, with its megacities and serene farmlands, was once dominated by dinosaurs as big as buses and five-story buildings.
But recent research has contributed to deepening our understanding why dinosaurs prevailed: the answer may lie in their special bones, structured like Aero chocolate.
Brazilian paleontologist Tito Aureliano discovered that hollow bones filled with small air sacs were so important for dinosaur survival, they evolved independently several times in different lineages.
According to the study, air bones evolved into three distinct lineages: pterosaurstechnically flying reptiles and two lines of dinosaurs, theropods (ranging from the raven-sized Microraptor to the huge tyrannosaurus rex) And sauropodomorphs (long-necked herbivores including Brachiosaurus).
The researchers focused on the end of the Triassicabout 233 million years ago, in southern Brazil.
Each time an animal reproduces, evolution generates random variants in the genetic code. Some of these variants are passed on to offspring and develop over time.
Charles Darwin believed that evolution created “most beautiful infinite shapes“. But some adaptations emerge spontaneously over and over again, much like getting the same hand of cards over and over.
When the same hand keeps coming backit is a sign that evolution has found an important and effective solution.
The variant studied by the Brazilian team was airy vertebrae bones, which would have improved the dinosaurs’ strength and reduced their body weight.
Light but powerful
Your regular deliveries from Amazon or other online retailers are packaged in corrugated cardboard, which has the same advantages as airy bones. It is light, but resistant.
Corrugated cardboard, or as it was first called, pleated paper, was a hugely successful artificial design experiment and is now part of our daily lives. It was patented in England in 1856 and was originally designed to support top hats, which were popular in Victorian England and the United States at the time.
Three years later, Darwin published his About the origin of species who described how evolutionary traits that create advantages are more likely to be passed on to future generations than variants that do not.
CT technology allowed Aureliano and his colleagues to look inside the rock-hard fossils they studied. Without modern technology, it would have been impossible to look inside fossils and detect air sacs in the spines.
The study found that no common ancestor had this trait. All three groups must have developed air sacs independently, and each time in slightly different ways.
The air sacs probably improved the blood oxygen levels of the dinosaurs. THE Triassic period had a torrid and dry climate. Thus, more oxygen circulating in the blood would more effectively cool the bodies of the dinosaurs. It would also allow them to move faster.
The air sacs would have buttressed and strengthened the internal structure of the dinosaurs’ bones while creating a greater surface area for attaching large powerful muscles.
This would have allowed the bones to grow to a much larger size without weighing the animal down.
In living birdsairy bones reduce overall mass and volume, while improving bone strength and stiffness – essential characteristics for flight.
Paleontology not only tells the story of what might have been for the Earth, but for that infamous asteroidbut also helps us learn about the evolution of creatures that are still alive.
Echoes of this dinosaur heritage are found in many animals alive today. It’s not just long-dead animals that have found this type of adaptation useful. A lot bird species the living today rely on hollow bones to fly.
Other animals use the air sacs to buttress and strengthen their large bones and skulls, without weighing them down.
A prime example of this is the elephant skull. Inside elephant skulls are large air sacs that allow the animal to move its massive head and heavy tusks without straining the neck muscles.
The human brain is also protected by two layers of hard, compact bone (inner and outer tables) which sandwich a layer of softer bone, spongy and airy bone between, known as a graduate. This allows our skulls to be lightweight, yet strong and able to absorb impact to the skull.
These are examples of convergent evolution in which animals repeatedly face the same problem, each time developing similar – but not always identical – solutions. Animals today play by the same evolutionary playbook as dinosaurs.
Sally Christine ReynoldsSenior Academic in Hominin Paleoecology, Bournemouth University
This article is republished from The conversation under Creative Commons license. Read it original article.