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Explore the similarities and differences in DNA, RNA, and proteins among species. Discover the evolutionary clues in cytochrome c sequences, vestigial organs, and homologous structures in comparative anatomy.
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Bio Chemistry • we can expect the DNA, RNA, and proteins of closely related species to show more similarities than those of distantly related species. • For example, the entire cytochrome c sequence is identical in humans and chimpanzees. It differs by 1 amino acid in rhesus monkeys, 18 in chickens, 19 in turtles, and 56 in yeasts. • Cytochrome C Sequence Whale G D V E K G K K I F V Q K C A Q C H T V E K G G K H K T G P N L H G L F G R K T G Q A V G F S Y T D AWolf G D V E K G K K I F V Q K C A Q C H T V E K G G K H K T G P N L H G L F G R K T G Q A P G F S Y T D A Shark G D V A K G K KT F V Q K C A Q C H T V E N G G K H KV G P N L W G L F G R K T G Q A E GY S Y T D A
Vestigial Organs • Organisms often have structures that have lost much or all of their original function through evolution but are similar to functional organs in other organisms. • The presence of such organs enables scientists to determine past and present relationships between groups of organisms. • Vestigial structures found in humans include • third eyelid (nictitating membrane), • appendix, tail vertebrae (coccyx), • ear muscles. • Also, vestigial structures found in whales include a pelvis and femur bones. Wolves have a pelvis and femur; sharks do not.
Whales evolved from land mammals • Whales and wolves are more closely related! • Then WHY are sharks and whales so similar???