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Which of the following taxonomic categories contains all the others listed here? |
class |
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Animals that possess homologous structures probably _____. |
evolved from the same ancestor |
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Systematists have used a wide variety of traits to reconstruct the phylogenies of particular groups of organisms. Which one of the following traits produces a good estimate of phylogeny? |
Behavioral traits -gross morphological traits -molecular traits -biochemical traits –Most researchers today appreciate that both morphology and molecular biology are essential sources of data for phylogenetic study. |
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By definition a clade is _____. |
monophyletic |
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Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character? |
shared ancestral character |
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What process actually increases the number of genes in an organism’s genome? |
gene duplication |
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Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago? |
DNA coding for rRNA changes relatively slowly |
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Molecular clocks are based on the idea that _____. |
on average neutral mutations arise at a constant rate |
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Which process occurred frequently in the early history of the three domains on Earth, and makes determining phylogenetic relationships of that time difficult? |
horizontal gene transfer |
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Which observation supports the position of eukaryotes at the convergence of the "ring of life"? |
the nuclear genome of eukaryotes contains genes from archaeans and from bacteria |
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In a comparison of birds and mammals, having four limbs is |
a shared ancestral character |
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To apply parsimony to constructing a phylogenetic tree, |
choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology |
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In Figure 26.4 in your textbook, which similarly inclusive taxon descended from the same common ancestor as Canidae? |
Mustelidae |
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Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U or V) makes up |
paraphyletic group |
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If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? |
wolf |
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The relative lengths of the frog and mouse branches in the phylogeny in Figure 26.13 in your textbook indicate that |
the homolog was evolved more slowly in mice |
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Phylogeny is the evolutionary history of related groups of organisms. Organisms are grouped into taxa based on homologous characteristics, shared traits that result from common ancestry. Which statement is true? |
the term "monophyletic" refers to a taxon that includes an ancestral species and all of its descendants |
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Which of these are homologous structures? |
ivy leaf and pine needle |
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Select the correct statement about phylogenetic trees. |
Phylogenetic trees may expand quickly to maximum width and then narrow over time |
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