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