Chapter 26

The best classification system is that which most closely _____. a. conforms to traditional, Linnaean taxonomic practices b. reflects evolutionary history c. reflects the basic separation of prokaryotes from eukaryotes d. unites organisms that possess similar morphologies

Some beetles and flies have antler-like structures on their heads, much like male deer do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of _____. a. convergent evolution b. a synapomorphy c. parsimony d. homology

Which of the following pairs are the best examples of homologous structures? a. bones in the bat wing and bones in the human forelimb b. bat wing and bird wing c. owl wing and hornet wing d. eyelessness in the Australian mole and eyelessness in the North American mole

The importance of computers and of computer software to modern cladistics is most closely linked to advances in _____. a. fossil discovery techniques b. radiometric dating c. light microscopy d. molecular genetics

The common ancestors of birds and mammals were very early (stem) reptiles, which almost certainly possessed three-chambered hearts (two atria, one ventricle). Birds and mammals, however, are alike in having four-chambered hearts (two atria, two ventricles). The four-chambered hearts of birds and mammals are best described as _____. a. structural homologies b. the result of shared ancestry c. vestiges d. homoplasies

Which of the following would be useful in creating a phylogenetic tree of a taxon? I) morphological data from fossil species II) genetic sequences from living species III) behavioral data from living species a. I b. II c. III d. I, II, and III

Your professor wants you to construct a phylogenetic tree of orchids. She gives you tissue from seven orchid species and one lily. What is the most likely reason she gave you the lily? a. to see if the lily and the orchids show all the same shared derived characters (synapomorphies) b. to serve as an outgroup c. to see if the lily is a cryptic orchid species d. to demonstrate likely homoplasies

Which of the following statements best describes the rationale for applying the principle of parsimony in constructing phylogenetic trees? a. Similarity due to common ancestry should be more common than similarity due to convergent evolution. b. Parsimony allows the researcher to "root" the tree. c. The outgroup roots the tree, allowing the principle of parsimony to be applied. d. The molecular clock validates the principle of parsimony.

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in _____. a. mutations to homologous genes b. the pattern of embryological development c. morphology d. biochemical pathways

There is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared _____. a. derived character of the amniote clade and not of the mammal clade b. derived character of mammals, even if cynodonts continue to be classified as reptiles c. derived character of mammals, but only if cynodonts are reclassified as mammals d. ancestral character of the amniote clade, but only if cynodonts are reclassified as mammals

If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup? a. leopard b. lion c. domestic cat d. wolf

Eukaryotes that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their _____. a. homologous genes that are highly conserved b. mitochondrial genomes c. plasmids d. homologous genes that are poorly conserved

The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma. These species have apparently undergone speciation from ancestral stock since the last glacial retreat about ten thousand years ago. Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species? a. conserved regions of nuclear DNA b. mitochondrial DNA c. amino acids in proteins d. ribosomal RNA

Which statement represents the best explanation for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology? Dogs and wolves _____. a. belong to the same order b. are both members of the order Carnivora c. have very similar morphologies d. share a very recent common ancestor

The most important feature that permits a gene to act as a molecular clock is _____. a. a recent origin by a gene-duplication event b. a reliable average rate of mutation c. a large number of base pairs d. being acted upon by natural selection

Neutral theory proposes that _____. a. a significant proportion of mutations are not acted upon by natural selection b. most mutations of highly conserved DNA sequences should have no functional effect c. molecular clocks are more reliable when the surrounding pH is close to 7.0 d. DNA is less susceptible to mutation when it codes for amino acid sequences whose side groups (or R-groups) have a neutral pH

Which portion of the figure above may ultimately be better depicted as a "ring"? a. the eukaryotic lineage b. the trunk of the tree c. the archaean lineage d. the bacterial lineage

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

Which of these are homologous structures? a. Ivy leaf and pine needle b. Plant root and plant leaf c. There are no homologous plant structures.

This figure shows a phylogenetic tree of birds and their close relatives. Identify the monophyletic taxon. a. Birds and dinosaurs and their common ancestor b. Birds and crocodiles and their common ancestor c. Birds and the common ancestor of dinosaurs and birds

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