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
reptiles by laying eggs. Aves have many characteristics that survival, amplification, and spread of these viruses. This is
differ from most reptiles as well. Reptiles are ectothermic important to know in order to stop the spread of diseases. If
while birds are endothermic. Birds also have developed a four vaccines could be created for birds, there could be a drastic decrease
chambered heart and hollow bones to aid them in flight while in these viral infections. It could also possibly lead to the
reptiles have a three chambered heart and dense solid bones. elimination natural reservoir, effectively killing the disease.
As a result of these various characteristics, it can be difficult Scales, however, do not facilitate the spread of diseases. Infecting
for some to pinpoint where in history birds have made their an animal with scales is much harder because it provides more
evolutionary ascent. Understanding when and why in history protection and does not carry germs as easily as feathers. The
certain traits have developed, may help us better understand evolution of scales from dinosaurs to feathers of the modern day
why certain adaptations such as feathers result in greater bird has had positive impacts on the species but are a growing
survival. The discoveries of certain fossils, like the concern for our community.
Archeopteryx, have helped evolutionary scientists and Future Predictions: As feathers developed they have become
paleontologists to get a better idea of where to place them. increasingly specialized in their form and function. Each Feather in a
Certain diseases can also be spread from feathers, so knowing birds plumage has a specific use. Some feathers are used for insulation
more information on feather evolution and morphology can such as the penguins use of small feathers and down to keep warm in
help us better understand how to prevent certain diseases. 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 such as with the peacock tail feathers (Roslyn and Robert 2011), or to
dinosaurs were very small, but eventually evolved with time. help camouflage an individual (Stoddard et al 2011). We believe that as
Theropods evolved the first feathers which provided time continues and evolution shapes the uses of feathers that they will
waterproofing and insulation. Certain specimen such as the become even more specialized. Alcids, a small water bird, have
Archeopteryx and Caudipteryx provide evidence of feathers developed feathers that when we increase insulation so that the bird
showing up on dinosaurs. Development of flight, four stays warmer when it is in the water (Ortega-Jimez et al 2010). Other
chambered hearts, and air sacks allowed birds to become possible adaptations include increased water resistance, increased
more efficient in flight. During the Mesozoic Era the avian variation in color and patterns, larger primary feathers to allowing for
assemblage is made up of two major lineages: the extinct increased glide ability, and decrease in down size to allow for more
Enantiornithes, and the Ornithurae. The Ornithurae gives rise smaller feathers to help insulate.
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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