This could very well be one of the most interesting things that nature has ever created, no I am not talking about the brain, I am talking about feathers. Believe it or not there have not always been things flying around in the sky. As long as life has been on this planet it has been mostly firmly secured to the ground, up until about 150 million years ago that all changed. Scientist are still trying to piece together exactly what happened but there is a general consensus on a few things, mainly how feathers developed. What is up for debate is how these feathers turned into instruments for flight.
First let’s talk about a few assumption. We have to assume that dinosaurs eventually evolved into birds, which I think is safe to say that most experts believe this happened. I am not saying all dinosaurs did, but many species eventually made this transition. Next and is by far the biggest one, that evolution is real and this is yet another wonderful example of it.
So let’s say that around 150 million years ago (there are many different fossils to back up this assertion) that certain species of dinosaurs began growing what would be the earliest feathers. These were mostly spiny protrusions without the filament hairs that accompany modern feathers. Surprisingly all reptiles have a gene that can be manipulated and turned on to have them grow these spines, even modern reptiles have this gene. And in experiments scientist manipulated these genes to get them to grow these same spines. Modern reptiles just do not use it as they do not have a use for this adaptation for whatever reason. With that being said let’s assume that one group of small dinosaurs began growing these spines. I would love to know what made this gene suddenly kick on, but we see all the time in nature that random mutations are possible, so this could just be a random mutation. Still I think it is interesting as to why this happened in the first place.
So again let’s just accept that this happened, which it is hard to argue otherwise. You have these small dinosaurs running around that have these primitive feathers all over their bodies. These provide some advantage, so the animals carrying the gene survive and reproduce. I have heard that at first these primitive feathers were there to help the dinosaurs, that were decreasing in size stay warm. Smaller animals have a harder time maintaining their body heat, so this adaptation would have helped in that sense. This is when the spines begin to grow the filaments that mimic modern feathers again to help keep the animal warm. These are still primitive, and incapable of flight, but we are on the right path.
Through many generations these feathers continue to evolve and develop until they are capable of sustaining the creature in flight. Now this is where a few things are important. One being the creature must be small and light weight, which I am not sure if dinosaurs had hollow bones but I do know that modern birds do have this adaptation. So whether this was a dinosaur trait or something that was later developed it again helped them take to the skies. Another thing that needed to happen was longer arms. Dinosaurs had very small arms ones that would be incapable of flight. But again after millions of years these arms got longer and were eventually covered with feathers.
This is what is mostly under debate is how the first dinosaur/bird took to the sky. It is either the top down or the bottom up theory. Some say that these creatures ran up hills flapping their wings and eventually figured out they could fly. Others say they figured it out by jumping from tree to tree and gliding at first then eventually taking flight. To me, and I am not an expert, I think that top down theory sounds more plausible. But this would mean the creatures were climbing trees and using them as nests and such and eventual launch points. I am not sure there is any evidence of early birds living in trees. It just seems odd to me that this thing would run on the ground and flap its makeshift wings and learn to fly. But if you really think about it this also makes sense, as these animals were probably ground dwellers. Perhaps both happened at the same time, when dealing with these things, again, it is silly to deal in absolutes.
Imagine the evolutionary advantage this would have created. For millions even billions nothing was in the air except for maybe insects, once these birds took flight it was a whole new ball game. Not only the predatory aspect but the escape ability of these animals would have helped as well. They no longer had to be faster or bigger to ward off predators they could simply fly away and live for another day. I am not sure an adaptation like this one had happened before in nature, except maybe the evolution of the eye. That would certainly have been a major advantage, but something that was perhaps developed for an entirely different purpose was a key instrument in taking to the sky. How something like a spine on the skin of a primitive reptile lead to these creatures eventually flying, that is very strange and fascinating at the same time.
I have been trying to think of another instance of this throughout nature and I cannot. This really makes me think of how creatures might develop and evolve on other planets. I cannot begin to imagine what kind of similar adaptations may occur. Things that were developed for one reason but were perfectly adapted for another. Nature, and evolution for that matter, are truly remarkable.
Check out this video on the evolution of feathers it is pretty neat.