Keel (bird anatomy) keel; and ratites (from "ratis", "raft" — referring to the flatness of the sternum), having a subtle keel structure or lacking one entirely. However, this classification has fallen into disuse as evolutionary studies have shown that many flightless birds have evolved from flighted birds. The current definition of Carinatae now includes all extant birds. Keel (bird anatomy) A keel or carina (plural carinae) in bird anatomy is an extension of the sternum (breastbone) which runs axially along the midline of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a
What a Difference a Day Makes (Grey's Anatomy) What a Difference a Day Makes (Grey's Anatomy) "What a Difference a Day Makes" is the twenty-second episode of the fifth season of the American television medical drama, "Grey's Anatomy" and the show's 100th episode overall. Written by series creator Shonda Rhimes and directed by Rob Corn, the episode was originally broadcast on the American Broadcasting Company (ABC) in the United States on May 7, 2009. "Grey's Anatomy" centers around a group of young doctors in training. In this episode, a wedding takes place. The episode received generally favorable reviews. The initial airing was viewed by 15.326 million people and