Alfred Hitchcock’s “The Birds” Discussing the Origin of Birds Suu Suu Zhou, Andy Gomez, Victor Garcia, Mona Moshfegh AP Biology Period 4

Background Information Birds are descendants of theropod dinosaurs. Charles Darwin suggested that all species are descended with modification from other species. Fossils often have features that are intermediate between those of an ancestral form and its descendants. These fossils help us understand how different groups of organisms living today are related.

Summary The origin of birds is a topic of great controversy in the ornitho-paleontological community Most dinosaurs do not resemble birds, but upon the discovery of the archaeopteryx, the shared features were evident There are other traits in dinosaurs that are in birds, which shows how birds are descended from the dinosaurs. Only the more birdlike dinosaurs (theropods) survived the mass extinction Birds are the modern dinosaurs

Species Descend From Other Species Key Concept: Species Descend From Other Species The Archaeopteryx Archaeopteryx fossils show that both living birds and living reptiles are related. The distinct birdlike features are clear in the wings, feathers, and digits Archaeopteryx is an ancestor of birds

Shared Anatomical Features Bones and Traits Key Concept: Shared Anatomical Features Traits of Theropods Wishbones Feathers (even if not for flying) Hollow bones Anatomical structure

Discussion Point 1 -Did birds evolve from dinosaurs? What kind of dinosaurs? -What similarities do birds have with dinosaurs?

Discussion Point 1 (cont.) -Birds evolved from theropods, which are dinosaurs that have two legs and three toes, as well as hollow bones. -Dinosaurs and birds share many physical characteristics such as bone structure and feathers

Discussion Point 2 In the video, Dr. Clarke says, “It was long assumed that feathers evolved for flight. But . . . clearly, feathers predate flight and arose for some other purpose.” Why is this significant? What caused the first feathers to appear? Why did the feather trait become more common? Did the feathers let them fly immediately, or did flight take a while to evolve?

Discussion Point 2 (cont.) Feathers were not developed solely for flight Mutation (a random process) caused the first feathers to appear Feathers might be beneficial for insulation or communication Flight was not immediate and the feathers gained use over time -the beginnings of feathers were the

Review Questions ON YOUR PAPER, WRITE THE ANSWER!~ What caused the first feathers to appear? Does having feathers mean you can fly? What traits does the T-Rex share with the chicken?🐓

ANSWERS Mutations Not necessarily Anatomical structures, such as Wishbones and Hollow bones

Thanks for listening!