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)
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?
ReplyDeletePosted by Michael Dailing
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.
ReplyDeleteLike 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
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.
ReplyDeleteNicole Peterkin
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.
DeleteMax Liner
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.
ReplyDelete-JE
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.
DeleteML