9 - BIOL 214 EXAM 2

If organisms A, B, and C belong to the same class but to different orders and if organisms D, E, and F belong to the same order but to different families, which of the following pairs of organisms would be expected to show the greatest degree of structural homology?

D and E

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

Homoplasies

Regarding these sequence homology data, the principle of maximum parsimony would be applicable in _____.

Inferring evolutionary relatedness from the number of sequence differences

A large proportion of archaeans are extremophiles, so called because they inhabit extreme environments with high acidity, salinity, and/or temperature. Such environments are thought to have been much more common on the primitive Earth. Thus, modern extremophiles survive only in places that their ancestors became adapted to long ago.

On a phylogenetic tree whose branch lengths are proportional to the amount of genetic change, the branches of the extremophiles should be shorter than the non-extremophilic archaeans.

Linnaeus believed that species remained fixed in the form in which they had been created. Linnaeus would have been uncomfortable with _____.

Phylogenies

Which eukaryotic kingdom includes members that are the results of endosymbioses that included an ancient aerobic bacterium and an ancient cyanobacterium

Plantae

Based on cladistics, which eukaryotic kingdom is polyphyletic and, therefore, unacceptable?

Protista

The best classification system is that which most closely

Reflect evolutionary history

The most important feature that permits a genes to act as a molecular clock is

a reliable average rate of mutation

In a comparison of birds and mammals, having four limbs is

a shared ancestral character

Neutral theory proposes that

a significant proportion of mutations is not acted upon by natural selection.

which of the following pairs are the best examples of homologous structure

bones in bat wing and bones in the human forelimb

A phylogentic tree constructed using sequence differences in mitochondrial DNA would be most valid for discerning the evolutionary relatedness of

chimpanzees and humans

To apply parsimony to constructing a phylogenetic tree,

choos the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology

there is some evidence that reptiles called cynodonts may have had whisker-like hairs around their mouths. If true, then hair is a shared

derived character of mammals, but only if cynodonts are re-classified as mammals.

The reason that paralogous genes can diverge from each other within the same gene pool, whereas orthologous genes diverge only after gene pools are isolated from each other, is that

having an extra copy of a gene permits modifications to the copy without loss of the original gene product

Eukaryotes that are not closely related and do not shared any anatomical similarities can still be placed together on same phylogenetic tree by comparing their

homologous genes that are highly conserved

the importance of computers and computer software to modern cladistics is most closely linked to advances in

molecular genetics

Phylogenetic trees constructed from evidence from molecular systematics are based on similarities in

mutations to homologous genes

Which of the following would, if it had acted upon a gene, prevent gene from acting as a reliable molecular clock

natural selection

Concerning growth in genome size over evolutionary time, which of these is LEAST associated with the other

orthologous genes

Which of the following is (are) problematic when the goal is to construct phylogenies that accurately reflect evolutionary history?

polyphyletic taxa and paraphyletic taxa

Some molecular data place the giant panda in the bear family (Ursidae) but place the lesser panda in the raccoon family (Procyonidae). Consequently, the morphological similarities of these two species are probably due to

possession of analogous (convergent) traits

which statement represents the best explanationary for the observation that the nuclear DNA of wolves and domestic dogs has a very high degree of sequence homology/ Dogs and wolves

share very recent common ancestor

The term homoplasy is most applicable to which of the following features?

the legless condition found in various lineages of extant lizards

The various taxonomic levels (for example, phyla, genera, classes) of the hierarchical classification system differ from each other on the basis of _____.

their inclusiveness

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?

to serve as an outgroup