Val Biology 26

Total Word Count: 392
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Which of the following taxonomic categories contains all the others listed here?

order
genus
species
family
class

class

Animals that possess homologous structures probably _____.

are not related
are headed for extinction
by chance had similar mutations in the past
have increased genetic diversity
evolved from the same ancestor

evolved from the same ancestor

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 estimates of phylogeny?

molecular traits
biochemical traits
behavioral traits
gross morphological traits
all of the above traits combined

all of the above traits combined

By definition a clade is _____

paraphyletic
monophyletic
polyphyletic
analogous
parsimonious

monophyletic

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

shared derived character
shared ancestral character
analogous character
polyphyletic character
cladistic character

shared ancestral character

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

parsimony
mutation
cladistics
gene duplication
independent assortment

gene duplication

Why do researchers use rRNA in investigations of relationships between taxa that diverged hundreds of millions of years ago?

rRNA is never the nucleic acid chosen for comparisons.
rRNA cannot mutate.
DNA coding for rRNA changes relatively slowly.
rRNA mutates rapidly.
rRNA is traditionally the nucleic acid chosen for recent comparisons.

DNA coding for rRNA changes relatively slowly.

Molecular clocks are based on the idea that _____.

mutations occur once every generation
directional selection occurs at a constant rate
molecules resonate at a certain frequency that can be measured
advantageous mutations arise at a constant rate
on average neutral mutations arise at a constant rate

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?

alternative RNA splicing
horizontal gene transfer
mitosis
meiosis
binary fission

horizontal gene transfer

Which observation supports the position of eukaryotes at the convergence of the "ring of life"?

Eukaryotes and archaeans both lack peptidoglycan in their cell walls.
Only eukaryotes perform mitosis.
The nuclear genome of eukaryotes contains genes from archaeans and from bacteria.
Introns are rare in both bacteria and archaeans.
Circular chromosomes are present in both bacteria and archaeans.

The nuclear genome of eukaryotes contains genes from archaeans and from bacteria.

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