BSC-116-001 Chapter 26

BSC-116-001 Chapter 26 Animals that possess homologous structures probably _____. A. have increased genetic diversity B. evolved from the same ancestor C. are not related D. are the result of convergent evolution E. are the result of similar environmental pressures in different evolutionary lineages - Answer- B. evolved from the same ancestor Homologous structures are similar because of common ancestry. By definition a clade is _____. A. parsimonious B. polyphyletic C. paraphyletic D. analogous E. monophyletic - Answer- E. monophyletic A clade is defined as a group that includes an ancestral species and all of its descendants. Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character? A. analogous character B. shared derived character C. polyphyletic character D. cladistic character E. shared ancestral character - Answer- E. shared ancestral character A shared ancestral character is one that originated in an ancestor of the taxon. In this case it appears that feathers originated in some dinosaur lineages and were passed down to birds. What process actually increases the number of genes in an organism's genome? What process actually increases the number of genes in an organism's genome? A.mutation B.parsimony C. gene duplication D. cladistics E. independent assortment - Answer- C. gene duplication Mutations that lead to duplications actually increase the number of genes in a genome. When an organism has two copies of a gene, one can perform its function while the other is free to accumulate mutations to the point that it may take on a new and advantageous function. Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago? A. rRNA is traditionally the nucleic acid chosen for recent comparisons. B. rRNA is never the nucleic acid chosen for comparisons. C. rRNA cannot mutate. D. DNA coding for rRNA changes relatively slowly. E. rRNA mutates rapidly. - Answer- D. DNA coding for rRNA changes relatively slowl