Scientists map 48 bird genomes, unlocking their dinosaur pasts

In early December, the mapping of genomes of 48 species of birds, representing various lines of ancestry, was completed. This greatly increased the amount of information available to study and gave information about bird's evolutionary connections to other animals. The genomes have been used to reconstruct the genome of the most recent common ancestor of birds, dinosaurs, and crocodiles. (Crocodiles are related more closely to birds than they are to other reptiles.) Some more understanding that this new information has given us has to do with how birds survived when dinosaurs went extinct and why there are so many different types of birds. Latest studies have suggested that birds did not break into all of these species until after the mass extinction of dinosaurs, because the small amount of birds that did survive adapted to fit all the niches left open from extinct species.

This connects with what we are learning in term 2 because it tracks the evolution of lots of different related species. This is an example of molecular data providing more evidence in taxonomy than fossils could alone. The connection between crocodiles and birds also challenges traditional classification, which would have grouped them separately. Grouping them together abides by the new effort to use cladistics to organize phylogenic trees solely based on derived characters. The survival and species variation of birds also relates to adaptive radiation. After the mass extinction at the end of the cretaceous period, surviving birds had many more niches to fill that were once filled with now-extinct species. This is similar to what the Galapagos finches experienced when colonizing the islands. Where on the mainland there was only one niche for them to fill, and so they were only one species, on the islands, which they were one of the first species to colonize, they were able to adapt to different isolated niches and become different species.

Feltman, Rachel. "Scientists map 48 bird genomes, unlocking their dinosaur pasts." Washington Post 11         Dec. 2014. Science in Context. Web. 11 Jan. 2015.

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