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SIGNATURES OF HISTORY Evidence to support Darwin’s idea of “Descent with Modification” “NOTHING IN BIOLOGY MAKES SENSE EXCEPT IN THE LIGHT OF EVOLUTION. ” --THEODOSIUS DOBZHANSKY GENETICIST, COLUMBIA UNIVERSITY WHY IS KNOWLEDGE OF EVOLUTION AND EVOLUTIONARY MECHANISMS NECESSARY?? • Evolutionary biology underpins the fields of • Genetics • Conservation Biology • Medicine • Immunology • Molecular Biology • Any field of life science! EVOLUTIONARY MECHANISMS • Natural Selection • Genetic Drift • Mutation • Gene Flow Darwin only discussed (and discovered) natural selection! LET’S GO TO THE VIDEO! • Evolutionary thinking MUST be applied to finding cures for diseases like HIV! • Single Drug Therapy (AZT) • Thymadine analog; targets growing DNA chain during reverse transcriptase • Multiple Drug Therapy (HAART) SO……… • What would you tell someone who wants to have unprotected sex? • What if he/she says…..”Don’t worry, HIV can be treated now with drugs!” ARE HUMANS EVOLVING DUE TO THE HIV EPIDEMIC?? • CCR5 d32 genotype of cell receptor proteins • CCR5 d32 is an allele that is MISSING 32 nucleotides (building blocks of DNA) • The coded protein is too short, and does not fold properly • HIV tries, but cannot enter the cell through this membrane protein! • That person is resistant! DESCENT WITH MODIFICATION • Let’s take a look at Anatomy and Physiology to see some glimpses of “Signatures of History” • We will also see these signatures at the molecular and cellular levels later on! METHODS OF LOCOMOTION • Gibbons Brachiating • To whom do we relate? CAUDAL FINS BALEEN WHALES….AND TEETH?? A SHELL-LESS SNAIL? I still move my anus!! Then I move it back! PHARYNGEAL POUCHES!! PREHENSILE FINGERS AND TOES PHOTOGRAPHIC EVIDENCE! YIKES! AND SO MANY MORE….. • Wisdom teeth • Darwin’s point • Ear muscles…can you wiggle your ears?? • Goose bumps!! WHAT’S THE POINT? • We are ALL products of Descent with Modification. • Since the 3.8 billion years living things have inhabited Earth, there have been very few NEW structures! • As Neil Shubin writes in “Your Inner Fish” [Our bodies] wouldn’t have been designed this way from scratch, any more than a rewiring job in a building.
