Short answers, pulled from the story.
Archaeopteryx lithographica was a fossil specimen from the Late Jurassic period about 155 million years ago that displayed both reptilian teeth and clawed fingers alongside wings covered in flight feathers. This creature provided early support for evolutionary theory by showing traits shared by both dinosaurs and modern birds.
Birds breathe differently than mammals because fresh air flows continuously through lungs during both inhalation and exhalation. About 75% of incoming air bypasses the lungs initially to fill posterior air sacs before entering lung tissue while the other 25% goes straight into the lungs.
In 2010 only two bird genomes had been sequenced but by recent years over 542 species had completed genomic analysis. At least one genome exists from every known order of living birds.
The Arctic tern holds records for longest migration traveling approximately 70,900 kilometers yearly between Greenland breeding grounds and Antarctic wintering areas. Sooty shearwaters make round trips up to 64,000 kilometers to summer feeding zones off Japan and Alaska.
Since the 17th century human activity has caused approximately 120 to 130 bird species to become extinct globally with hundreds more disappearing before that period. Current extinction threats face about 1,200 remaining species due to habitat loss climate change and direct persecution.