Question 1

From the above figure,what is true of Dryopithecus and Ouranopithecus?
1)They were great apes.
2)They shared a common ancestor more recently with the orangutans than with the other great apes.
3)They appear to be part of a polytomy.
4)Their closest common ancestor with all of the extant great apes is the one they share with the orangutans.
5)They were about as different from each other genetically as humans are different from chimps.

Accepted Answer

A) 1, 2, and 4 
B) 1, 3, and 4 
C) 2, 4, and 5 
D) 1, 2, 3, and 4 
E) 2, 3, 4, and 5

Question 2

Which mutation should least require realignment of homologous regions of a gene that is common to several related species?

Accepted Answer

A) three-base insertion 
B) one-base substitution 
C) four-base insertion 
D) one-base deletion 
E) three-base deletion

Question 3

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

Accepted Answer

A) structural homologies. 
B) vestiges. 
C) homoplasies. 
D) the result of shared ancestry. 
E) molecular homologies.

Question 4

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

Accepted Answer

A) inheritance of acquired characteristics. 
B) sexual selection. 
C) inheritance of shared derived characters. 
D) possession of analogous structures. 
E) possession of shared primitive characters.

Question 5

The following questions refer to the description below.
You are taking an art class and your instructor asks you to draw several animals,including a shark,a dolphin,and a penguin.As you draw these animals you notice that they all have a fusiform shape; in other words,they are tapered at both ends.Despite their similar shape,you are well aware that the shark is a fish,the dolphin is a mammal,and the penguin is a bird.
-What is the best explanation for the similarities and differences in these three species?

Accepted Answer

A) There is some homology and some analogy in all living organisms. 
B) The animals all share a very distant common ancestor. 
C) You are seeing an example of convergent evolution: the evolution of similar traits in distantly related organisms due to adaptations to similar environments. 
D) You are seeing an example of homology: the evolution of similar function in distantly related organisms due to adaptations to similar environments. 
E) You are seeing an example of analogy: the evolution of modified traits in related organisms.

Question 6

Which of these four gene parts should allow the construction of the most accurate phylogenetic tree,assuming that this is the only part of the gene that has acted as a reliable molecular clock?

Accepted Answer

A) Intron I 
B) Exon I 
C) Intron VI 
D) Exon V

Question 7

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

Accepted Answer

A) light microscopy. 
B) radiometric dating. 
C) fossil discovery techniques. 
D) Linnaean classification. 
E) molecular genetics.

Question 8

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

Accepted Answer

A) archaeans and bacteria. 
B) fungi and animals. 
C) chimpanzees and humans. 
D) sharks and dolphins. 
E) mosses and ferns.

Question 9

The various taxonomic levels (namely,genera,classes,etc.)of the hierarchical classification system differ from each other on the basis of

Accepted Answer

A) how widely the organisms assigned to each are distributed throughout the environment. 
B) their inclusiveness. 
C) the relative genome sizes of the organisms assigned to each. 
D) morphological characters that are applicable to all organisms.

Question 10

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?

Accepted Answer

A) mtDNA 
B) rRNA genes 
C) morphological 
D) ecological

Question 11

The following questions refer to this phylogenetic tree,depicting the origins of life and of the three domains.Horizontal lines indicate instances of gene or genome transfer.
  
A possible phylogenetic tree for the three domains of life.
-Which portion of the above figure may ultimately be better depicted as a "ring"?

Accepted Answer

A) the bacterial lineage 
B) the archaean lineage 
C) the eukaryotic lineage 
D) the trunk of the tree 
E) the part corresponding to the first living cell on Earth

Question 12

Paralogous genes that have lost the function of coding for any functional gene product are known as "pseudogenes." Which of these is a valid prediction regarding the fate of pseudogenes over evolutionary time?

Accepted Answer

A) They will be preserved by natural selection. 
B) They will be highly conserved. 
C) They will ultimately regain their original function. 
D) They will be transformed into orthologous genes. 
E) They will have relatively high mutation rates.

Question 13

Which kind of DNA should provide the best molecular clock for determining the evolutionary relatedness of several species whose common ancestor became extinct billions of years ago?

Accepted Answer

A) that coding for ribosomal RNA 
B) intronic DNA belonging to a gene whose product performs a crucial function 
C) paralogous DNA that has lost its function (i.e., no longer codes for functional gene product) 
D) mitochondrial DNA 
E) exonic DNA that codes for a noncrucial part of a polypeptide

Question 14

Use the following information to answer the questions below.
Traditionally,zoologists have placed birds in their own class,Aves.More recently,molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals.Genetically,birds are more closely related to crocodiles than crocodiles are to turtles.Bird anatomy has become highly modified as birds have adapted to flight,without their genes having undergone nearly as much change.
-Taxonomically,what should be done with the birds?

Accepted Answer

A) The traditional stance is correct. Such dramatic morphological change as undergone by birds merits that the birds be placed in their own order, separate from the reptiles. 
B) The birds should be reclassified, and their new taxon should be the subclass Aves. Genetic similarity trumps morphological dissimilarity. 
C) The rest of the reptiles should be reclassified as a subclass within the class Aves. 
D) Science is consensual. Taxonomy is a science. Variant classification schemes involving the birds should be tolerated until consensus is reached.

Question 15

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

Accepted Answer

A) polyphyletic taxa 
B) paraphyletic taxa 
C) monophyletic taxa 
D) Two of the responses are correct.

Question 16

The lakes of northern Minnesota are home to many similar species of damselflies of the genus Enallagma that have apparently undergone speciation from ancestral stock since the last glacial retreat about 10 000 years ago.Sequencing which of the following would probably be most useful in sorting out evolutionary relationships among these closely related species?

Accepted Answer

A) nuclear DNA 
B) mitochondrial DNA 
C) small nuclear RNA 
D) ribosomal RNA 
E) amino acids in proteins

Question 17

The legless condition that is observed in several groups of extant reptiles is the result of

Accepted Answer

A) their common ancestor having been legless. 
B) a shared adaptation to an arboreal (living in trees)lifestyle. 
C) several instances of the legless condition arising independently of each other. 
D) individual lizards adapting to a fossorial (living in burrows)lifestyle during their lifetimes.

Question 18

The following questions refer to this phylogenetic tree,depicting the origins of life and of the three domains.Horizontal lines indicate instances of gene or genome transfer.
  
A possible phylogenetic tree for the three domains of life.
-Which of these processes can be included among those responsible for the horizontal components of the above figure?

Accepted Answer

A) endosymbiosis 
B) mitosis 
C) binary fission 
D) point mutations 
E) S phase of the cell cycle

Question 19

Use the following information to answer the questions below.
Traditionally,zoologists have placed birds in their own class,Aves.More recently,molecular evidence has shown that birds are more closely related to reptiles than their anatomy reveals.Genetically,birds are more closely related to crocodiles than crocodiles are to turtles.Bird anatomy has become highly modified as birds have adapted to flight,without their genes having undergone nearly as much change.
-For a proponent of PhyloCode classification,what is true of the reptile clade if birds are not included in it?

Accepted Answer

A) It becomes paraphyletic and, thus, an invalid reflection of evolutionary history. 
B) It becomes a subclass, instead of a class. 
C) It becomes a superclass, whereas the birds remain a class. 
D) PhyloCode does not concern itself with what is, or is not, a clade.

Question 20

To apply parsimony to constructing a phylogenetic tree

Accepted Answer

A) choose the tree that assumes all evolutionary changes are equally probable. 
B) choose the tree in which the branch points are based on as many shared derived characters as possible. 
C) base phylogenetic trees only on the fossil record, as this provides the simplest explanation for evolution. 
D) choose the tree that represents the fewest evolutionary changes, either in DNA sequences or morphology. 
E) choose the tree with the fewest branch points.

Exam 26: Phylogeny and the Tree of Life