CHP 26 Mastering Biology

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

Which of the following statements best describes the rationale for applying the principle of maximum parsimony in constructing phylogenetic trees?

For trees based on morphology, the most parsimonious tree requires the fewest evolutionary events.

Which of the following statements is accurate, at least according to our present knowledge?

Genes from prokaryotes have been acquired by some eukaryotes; these genes can allow survival in extreme environments

Which of the following statements is accurate with regard to a phylogeny, as represented by a phylogenetic tree?

Members of the same clade likely share many derived characters.

The kingdom Monera was dismantled because of which of the following reasons?

Monera contained organisms from other domains

Select the correct statement about phylogenetic trees.

Phylogenetic trees may expand quickly to maximum width and then narrow over time.

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

Plantae

In a ________ the branch point drawn farthest to the left represents the most recent common ancestor of all taxa in the tree.

Rooted Phylogenetic Tree

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.

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 paraphyletic group

Which of the following features permits a gene to act as a molecular clock?

a reliable average rate of mutation

To apply parsimony to constructing a phylogenetic tree,

choose the tree that represents the fewest evolutionary changes, in either DNADNA sequences or morphology.

Some beetles and flies have antler-like structures on their heads, much like male deer. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of which of the following?

convergent evolution

Which of the following evolutionary processes or characteristics would most likely result in an archaean species whose rRNA is more similar to that of humans of mice?

convergent evolution

Animals that possess homologous structures probably

evolved from the same ancestor

What process actually increases the number of genes in an organism's genome

gene duplication

Which of the following statements explains why 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?

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

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

The genome of an organism

includes all of the organism's DNA.

By definition a clade is _____.

monophyletic A clade is defined as a group that includes an ancestral species and all of its descendants.

Systematists have used a wide variety of traits (characters) to reconstruct the phylogenies of particular groups of organisms. Which of the following types of characters are used to estimate a phylogeny?

morphological characters and DNA sequence characters ( phylogenies are primarily inferred from morphological and DNA data

Which of the following information would be most useful in creating a phylogenetic tree of a taxon?

morphological data from fossil and living species

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

natural selection

Molecular clocks are based on the idea that __________.

on average, neutral mutations arise at a constant rate

Carolus Linnaeus believed that species remained fixed in the form in which they had been created. Which of the following concepts are inconsistent with Linnaeus's model of classification?

phylogenies

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

polyphyletic taxa and paraphyletic taxa

What kind of evidence has recently made it necessary to assign the prokaryotes to either of two different domains, rather than assigning all prokaryotes to the same kingdom?

rRNA genes

If additional DNA sequence evidence shows that yeast genes for synthesizing proteins are more similar to protein-synthesizing genes in bacteria than those in archaea, what would a systematist do with the current phylogeny?

redraw the phylogeny to show eukaryotes sharing a more recent common ancestor with bacteria than archaea

Fossil evidence indicates that some dinosaurs had feathers. If birds are indeed descended from dinosaurs, feathers are what kind of character?

shared ancestral character

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

shared ancestral character

Birds and mammals have four limbs. Which of the following statements describes this trait?

the trait is a shared ancestral character

Which of the following statements describes a difference between the taxonomic levels of the hierarchical classification system?

their inclusiveness