Essay Questions Set #2
Due: January 26, 2017
Question Number 2: Find an article about the phylogeny of any group of organisms that interest you and write a summary of the article. In a concluding paragraph, explain what you learned by reading the article.
The article “Feathered Non- Avian Dinosaurs from North America Provide Insight into Wing Origins” details a discovery that allows the expansion of the phylogeny of feathered non-avians. Remains were found in Canada of bird-like dinosaurs known as ornithomimosaurs. These fossils were interesting in that they appear to have feathers and that they were found in an area with rougher soil than usual. There are three skeletons; one juvenile and two adults. The juvenile, which they approximate …show more content…
The first adult is incomplete like the juvenile but here they are able to see the filaments spreading along the back and neck. The third skeleton, an adult, shows shafted feathers These feathers are very similar to those of modern birds. It appears that these birds have two different plumages in their lifetimes as the juvenile only has filamentous feathers while the adults have both filamentous and a pennibrachium. This indicates that these individuals do not have all their feathers until they mature into adults. This gives insight into potential mistakes made in the past when gathering information from juvenile individuals of a species; scientists may not have all the information simply because the individual they are inspecting is not at its full form until it is an adult. The pennibrachium is a “wing-like structure consisting of elongate feathers” and its presence indicates that feathers may have existed earlier than we believe. It is difficult to say why this terrestrial species evolved feathers as they probably did not use them for flight or for escaping predators. They believe it may a sexual characteristic that developed over time. It is of importance that these skeletons were found in course soil as it was believed that