Bio171-F08-lec33 - Lecture 33 Wednesday Biology 171...

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Unformatted text preview: Lecture 33: Wednesday November 19, 2008 Biology 171 Today’s Topic: Highlights of Vertebrate Evolution: Whales & Birds Announcements This Week in Discussion: Ant-fungal coevolution Text Reading Lec 33: 2 nd ed: Chapter 26 (559-561); Ch. 33 (760-1) 3 rd ed: Chapter 27 (546-548); Ch. 34 (748-749) Lec 34: 2 nd ed: Chapter 25 (553); Ch 26 (566-567); Ch 33 (773-778) 3 rd ed: Chapter 34 (762-767) Overview of Marine Mammals Baleen & Toothed Whales Whale Evolution: Molecules, Fossils and Recent Resolution What’s a Bird? Archaeopteryx Dinosaur Phylogeny and Bird Origins Highlights of vertebrate evolution: invasions of the Sea and Sky Convergent Streamlining * * * Give birth at sea- are fully marine Marine Mammals Mammalian Molecular Phylogenies (Gene Trees) Show that the Primary Marine Mammal Groups Represent Three Independent Marine Radiations Marine Mammal Physiological Diving Adaptations Exchange up to 90% of lung volume per breath Greater blood, erythrocyte (rbc) volumes; enhanced oxygen loading capacity Bradycardia (slowed heartbeat while submerged) Restricted blood circulation while submerged Collapsing lungs avoids supersaturing blood at depth and prevents “the bends” when ascending Blue Whales The largest animal species that has ever lived on earth Cetaceans (Whales): 75 spp. Mysticeti (Baleen) Odontoceti (Toothed) Humpback Whale Migration Routes Connecting High Latitude Feeding Areas and Low Latitude Breeding/Calving Areas Whaling nearly wiped this species out, reducing world populations to perhaps as low as 1,000 individuals by the mid-1960s. Today, estimates put the total at roughly 30,000. They are considered at high risk of extinction by the World Conservation Union. Humpback whale mother & calf Birth occurs in the Tropics During the breeding season, in the tropics, male humpbacks deliver very long and complex songs that may undergo change from year to year within a population Male in Head-Down Singing Posture Group Bubble Ring Feeding by Humpbacks is Used to Ef¡ciently Prey on Herring Shoals http://www.youtube.com/watch?v=vJvfjiCTvq4&feature=related Baleen Plates function by straining small prey from mouthfuls of seawater...
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Bio171-F08-lec33 - Lecture 33 Wednesday Biology 171...

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