1. Introduction: The Aves class has always been an
interesting portion of the evolutionary tree of vertebrates. Significance: An adaptive evolutionary trait of birds that
While observing their anatomy and physiology they appear to evolved from dinosaurs was feathers. They evolved from scales and
have characteristics of various classes. Birds are bipedal, allow birds to travel great distances, but this also created a
endothermic, egg-laying, feathered, vertebrates. Birds’ feet problem. The issue is that now they can also facilitate the spread of
have a keratinized outer layer (stratum corneum) that is diseases. Birds are reservoirs for certain diseases such as Influenza
homologous to the scales of reptiles. Birds also reproduce like and West Nile Virus. As a host, it allows the survival, amplification,
reptiles by laying eggs. Aves have many characteristics that and spread of these viruses. This is important to know in order to
differ from most reptiles as well. Reptiles are ectothermic stop the spread of diseases. If vaccines could be created for birds,
while birds are endothermic. Birds also have developed a four there could be a drastic decrease in these viral infections. It could
chambered heart and hollow bones to aid them in flight while also possibly lead to the elimination natural reservoir, effectively
reptiles have a three chambered heart and dense solid bones. killing the disease. Scales, however, do not facilitate the spread of
As a result of these various characteristics, it can be difficult diseases. Infecting an animal with scales is much harder because it
for some to pinpoint where in history birds have made their provides more protection and does not carry germs as easily as
evolutionary ascent. Understanding when and why in history feathers. The evolution of scales from dinosaurs to feathers of the
certain traits have developed, may help us better understand modern day bird has had positive impacts on the species but are a
why certain adaptations such as feathers result in greater growing concern for our community.
survival. The discoveries of certain fossils, like the
Archeopteryx, have helped evolutionary scientists and
paleontologists to get a better idea of where to place them.
Future Predictions: As feathers developed they have become
Certain diseases can also be spread from feathers, so knowing increasingly specialized in their form and function. Each Feather in a
more information on feather evolution and morphology can birds plumage has a specific use. Some feathers are used for insulation
help us better understand how to prevent certain diseases. such as the penguins use of small feathers and down to keep warm in
the cold temperatures of their environment (Du et al 2007). Some birds
grow feathers that aid in long migratory flights like Migratory Blackcaps
Evolutionary History: Well preserved and many new
(De La Hera et al 2007). Other feathers are specialized in color, size and
fossils have provided us with new evidence in respect to the
even make up. The color of the feathers can be for attracting a mate
evolution of dinosaurs to birds from 1994-2004. Early dinosaurs
such as with the peacock tail feathers (Roslyn and Robert 2011), or to
were very small, but eventually evolved with time. Theropods
evolved the first feathers which provided waterproofing and help camouflage an individual (Stoddard et al 2011). We believe that as
insulation. Certain specimen such as the Archeopteryx and time continues and evolution shapes the uses of feathers that they will
Caudipteryx provide evidence of feathers showing up on become even more specialized. Alcids, a small water bird, have
dinosaurs. Development of flight, four chambered hearts, and developed feathers that when we increase insulation so that the bird
air sacks allowed birds to become more efficient in stays warmer when it is in the water (Ortega-Jimez et al 2010). Other
flight. During the Mesozoic Era the avian assemblage is made possible adaptations include increased water resistance, increased
up of two major lineages: the extinct Enantiornithes, and the variation in color and patterns, larger primary feathers to allowing for
Ornithurae. The Ornithurae gives rise to all modern birds. Much increased glide ability, and decrease in down size to allow for more
of the diversity of the bird species are highlighted in the Early smaller feathers to help insulate.
Cretaceous Era. Much controversy still surrounds many of these
findings and we still require more evidence and information to
better understand the evolution of birds.
References
1. 6.
2. 7.
3. 8.
4. 9.
5. 10.