1) Feathers evolved from scales in dinosaurs and allowed for flight, but also facilitated the spread of diseases between birds. 2) Birds act as reservoirs for diseases like influenza and West Nile virus. Vaccines for birds could decrease these viral infections and possibly eliminate diseases. 3) Over time, feathers became more specialized for functions like insulation, flight, and mating displays. Future feather adaptations may include increased water resistance or variations in color.

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