Wednesday, March 5, 2014

Design Behind Flight May have Arose Earlier Than Previously Thought

The evolution of flight has baffled scientists for ages. Many theories have arisen in attempts to explain this marvelous phenomenon, but a new study suggests the evolutionary process may have begun much earlier than previously depicted. The common notion in circulation is the adaptive feather theory. This theory suggests that feathers became present as a by-product of evolution; rising from a mutation in set of genes that also code for hair and scales in other species. These genes, known as box-set-genes, have been mainly unaltered for millions of years. However, mutations have arisen over time, and as a result, feathers became available to early dinosaur-bird-like species. The bird evolutionary branch has two major extant divisions that biologists agree on. These are the ratites (flightless birds) and the neornithes (modern birds). The idea behind the rise of feathers is that they gave early bird species some benefit in either running faster, escaping prey, or attracting a mate. Which mechanism is unknown, possibly all of them, but fossil evidence suggests the presence of an ancient bird-like creature that had feathers not capable of flight. And so the adaptive flight theory is born.
A new study looking at elements preceding the evolution of flight, such as, arm length and body size, among earlier species of birds, suggest this process began much earlier than previously mentioned. A 2014 articles states, “Being small and light is important for a flyer, and it now seems a whole group of dozens of little dinosaurs were lightweight and had wings of one sort or another. Most were gliders or parachutists, spreading their feathered wings, but not flapping them”. This is an interesting idea and supports the adaptive feather theory. Often, evolution takes many steps, twists, and turns to produce an observable outcome. It's known that mutations in the genes coding for hair and scales gave rise to feathers, and adaptions in the morphology and functionality of arm length/ body size both are a major influence in the rise of flight. Researcher Mark Puttick stated, "We were really surprised to discover that the key size shifts happened at the same time, at the origin of Paraves," said Mr Puttick of Bristol's School of Earth Sciences. "This was at least 20 million years before the first bird, the famous Archaeopteryx, and it shows that flight in birds arose through several evolutionary steps."
Evolution is never as clear cut as it seems on paper. New fossil evidence, new studies, and predictions made based on previous studies/fossils help give insight into how life evolves. It is an ever-changing science that is subject to the latest research and discovery to guide us further. This newest development supports and complements previous theories regarding flight, as well as, provides new insight in an area previously not so well understood. It takes scientist challenging and comparing every aspect of nature, genetics, and development among species to get a clear cut picture of the evolution occurring. This newest studying is guiding us in the right direction of one day fully understanding the mysteries behind flight.  
posted by Maxwell Liner (5)


  1. Gliding and parachuting is an interesting theory for the function of these dinosaurs. What is the mechanism by which we can be sure that they never flapped but only glided? It is clear that flight capabilities and preferences are quite varied and across a variety of organisms. Who knows what fossil evidence will turn up?

    Posted by Michael Dailing

  2. This is an understandable, potentially legitimate way that feathers and wings and thus bird flight evolved. I do not recall exactly which insect it was, but I once learned that flight initially evolved (likely separately, through convergent evolution) in insects, again through gliding and parachuting. Insects that lived in the treetops may have needed to escape predators, or even accidentally fall from very high. While they would have likely survived the impact because they are so light and have an exoskeleton, they developed small limbs that helped them steer, maybe to a nearby tree trunk so they could reclimb more quickly.
    Like you said, evolution is never quite as clear cut as it seems, but I think this was the path of convergent evolution for flight in insects.

    Posted by Steven Yu

  3. It's often quite amazing the endless series of random mutations that have to occur for a ability to arise. rom the mutation to express one gene to another in scale cells to produce feathers instead is quite remarkable, but the patterns and weight parameters that were acquired via sexual and natural selection and genetic drift and eventually lead to the ability of flight.

    Nicole Peterkin

    1. I agree, its truly remarkable that the exact number of mutations and proper sequence of interactions between all these forces happened at precisely the right time in order to produce the species capable of flight that we see today.

      Max Liner

  4. Running faster, escaping prey, or attracting a mate would all be good reasons to have feathers. However, I think another important one is for keeping warm. Feathers, from what I understand, probably first evolved primarily for insulation, and were then developed into flight feathers.


    1. That's a really interesting thought and I would like to read more into it. Fossil evidence suggest early bird like species had feathers but lacked the ability to fly. However, they don't give any insight into which mechanism was the bigger player in the game. I think that's a great theory and given the right time and place held just as much value as any of the other ideas I mentioned above.