8. a) As you know, the largest mass extinction in the history of life on earth was the Permian extinction that occurred about 252 million years ago. The therapsids are often described as “mammal-like reptiles”. If the Permian extinction had caused the extinction of the therapsids, would mammals as we know them now have evolved? Why or why not? 8. b) Many lines of evidence, including biochemical evidence, show that living birds are direct descendants of dinosaurs. A number of dinosaur lineages had feathered dinosaurs, not just the lineage that includes living birds. Do you think that is it justified to believe that all feathered dinosaurs had behaviors known from living birds? Such behaviors of birds include colonial nesting, sexual displays by males using feathers, males moving to display their ornamental feathers to female mates. Give a brief reason for your answer. 8. c) A number of scientists believe that the Permian extinction was caused by huge volcanic lava flows (from the Siberian traps) that may have caused low oxygen concentrations compared to the high oxygen levels in the Permian. Does this low oxygen level after the Permian extinction make it likely that dinosaurs, especially large ones, did not evolve immediately after the Permian extinction (252 million years ago)? Why or why not?

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

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Hello, I need help answering number 8 a, b, & c using the phylogeny below. Pls & thank you! 8. a) As you know, the largest mass extinction in the history of life on earth was the Permian extinction that occurred about 252 million years ago. The therapsids are often described as “mammal-like reptiles”. If the Permian extinction had caused the extinction of the therapsids, would mammals as we know them now have evolved? Why or why not? 8. b) Many lines of evidence, including biochemical evidence, show that living birds are direct descendants of dinosaurs. A number of dinosaur lineages had feathered dinosaurs, not just the lineage that includes living birds. Do you think that is it justified to believe that all feathered dinosaurs had behaviors known from living birds? Such behaviors of birds include colonial nesting, sexual displays by males using feathers, males moving to display their ornamental feathers to female mates. Give a brief reason for your answer. 8. c) A number of scientists believe that the Permian extinction was caused by huge volcanic lava flows (from the Siberian traps) that may have caused low oxygen concentrations compared to the high oxygen levels in the Permian. Does this low oxygen level after the Permian extinction make it likely that dinosaurs, especially large ones, did not evolve immediately after the Permian extinction (252 million years ago)? Why or why not? Photos reference: Futuyma, D. J., & Kirkpatrick, M. (2017). Chapter 17 The History of Life. In Evolution (4th ed., pp. 430-467). Sunderland, Massachusetts: Sinauer Associates.