Ch 20 MB

Select the correct statement about phylogenetic trees. A. All phylogenetic trees are similarly shaped. B. Phylogenetic trees may expand quickly to maximum width and then narrow over time. C. Phylogenetic trees always show increased branching, representing increased diversity over time

Which of these are homologous structures? A. There are no homologous plant structures. B. Ivy leaf and pine needle C. Plant root and plant leaf

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? A. Homologous structures look the same and serve the same function, but they differ in evolutionary origin and structure. B. The term "monophyletic" refers to a taxon that includes an ancestral species and all of its descendants. C. Ancestral traits are always simpler than derived traits.

In a comparison of birds and mammals, the condition of having four limbs is __________. A. a shared derived character B. a character useful for distinguishing birds from mammals C. a shared ancestral character D. an example of analogy rather than homology

To apply parsimony to constructing a phylogenetic tree, __________. A. choose the tree that assumes all evolutionary changes are equally probable B. choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology C. choose the tree with the fewest branch points D. choose the tree in which the branch points are based on as many shared derived characters as possible

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 __________. A. a paraphyletic group B. a polyphyletic group C. a monophyletic taxon D. an ingroup, with species U as the outgroup

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? A. wolf B. frog C. leopard D. domestic cat

The relative lengths of the frog and mouse branches (frog being longer) in the phylogenetic tree in the figure given below indicate that __________. A. the homolog has evolved more slowly in mice B. mice evolved before frogs C. the homolog has evolved more rapidly in mice D. frogs evolved before mice

Which of the following taxonomic categories contains all the others listed here? A. genus B. species C. order D. family E. class

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 similar environmental pressures in different evolutionary lineages E. are the result of convergent evolution

Systematists have used a wide variety of traits to reconstruct the phylogenies of particular groups of organisms. Which one of the following traits produces good estimates of phylogeny? A. gross morphological traits B. behavioral traits C. molecular traits D. biochemical traits E. all of the above traits combined

By definition a clade is __________. A. paraphyletic B. polyphyletic C. parsimonious D. monophyletic E. analogous

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. cladistic character C. polyphyletic character D. shared derived character E. shared ancestral character

Molecular clocks are based on the idea that __________. A. molecules resonate at a certain frequency that can be measured B. directional selection occurs at a constant rate C. advantageous mutations arise at a constant rate D. mutations occur once every generation E. on average, neutral mutations arise at a constant rate

Which process occurred frequently in the early history of the three domains on Earth and makes determining phylogenetic relationships of that time difficult? A. meiosis B. alternative RNA splicing C. horizontal gene transfer D. binary fission E. mitosis

What process actually increases the number of genes in an organism's genome? A. cladistics B. mutation C. gene duplication D. parsimony E. independent assortment