Question 1

-The best classification system is that which most closely

Accepted Answer

The most accurate and useful classification system is one that reflects evolutionary history, as it reflects the relationships and genetic similarities between organisms. Morphologies can be deceiving and do not always accurately depict evolutionary relationships, and traditional Linnaean taxonomic practices are outdated and not necessarily reflective of true relationships. Separating prokaryotes from eukaryotes is only one aspect of classification and does not provide a comprehensive classification system.

Question 2

Linnaeus was a "fixist" who believed that species remained fixed in the form in which they had been created.Linnaeus would have been uncomfortable with

Accepted Answer

Linnaeus' belief in fixed species would conflict with the concept of phylogenies, which suggest evolution and changes in species over time based on their ancestral relationships.

Answer: D
 Linnaeus' fixed species concept would not allow for the idea of nested, ever-more inclusive categories of organisms, as it implies that there is a continuum of change and evolution over time.

Answer: E
 Linnaeus' belief in fixed species would conflict with the hierarchical classification scheme, which is based on evolutionary relationships and suggests that organisms have changed over time and been influenced by their environment.

Question 3

If,someday,an archaean cell is discovered whose rRNA sequence is more similar to that of humans than the sequence of mouse rRNA is to that of humans,the best explanation for this apparent discrepancy would be

Accepted Answer

Homoplasy refers to a similarity in the structure or genetic sequence of different species that is due to convergent evolution rather than to descent from a common ancestor. In the scenario described, the surprising similarity between human rRNA and that of an archaean cell, more so than between humans and mice, would likely be due to convergent evolution (homoplasy), rather than direct common ancestry. This is because archaea and humans are very distantly related on the evolutionary tree, with mice being much closer relatives to humans.

Question 4

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

Accepted Answer

Polyphyletic and paraphyletic taxa are problematic for constructing accurate phylogenies because they do not represent natural groups derived from a common ancestor. Polyphyletic groups consist of species with similar characteristics but different ancestors, while paraphyletic groups include some, but not all, descendants of a common ancestor. Monophyletic taxa, which include an ancestor and all its descendants, are ideal for reflecting evolutionary history.

Question 5

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

The morphological similarities between the giant panda and the lesser panda, despite their placement in different families based on molecular data, suggest that these similarities are due to analogous structures. Analogous structures arise from convergent evolution, where unrelated species develop similar traits independently, often due to similar environmental pressures or ecological roles, rather than from a common ancestor.

Question 6

Consider the human arm,a dog's foreleg,and a seal's flipper.These three structures are examples of ________ structures.

Accepted Answer

Homologous structures are similar structures in different species that have a common ancestry. The human arm, dog's foreleg, and seal's flipper are all similar in bone structure and arrangement, indicating they evolved from a common ancestor. Analogous structures are structures with similar function but different origins, while the terms mammalian and related are too broad and do not accurately describe the specific structures in question.

Question 7

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

Accepted Answer

The existence of antler-like structures in different animal groups that have strong male-male competition is an example of convergent evolution. This means that these structures evolved independently in different groups due to similar selective pressures, rather than being inherited from a common ancestor (synapomorphy) or being homologous structures. In this case, the antler-like structures in beetles, flies, and deer are not anatomically similar and have evolved through different developmental pathways, indicating convergent evolution. Parsimony is a principle used in phylogenetic analysis to choose the simplest explanation; it is not relevant to this scenario.

Question 8

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

Accepted Answer

The taxonomic levels differ from each other based on their inclusiveness. Each level includes a progressively smaller group of organisms that share more specific characteristics. For example, a class includes multiple orders, while an order includes multiple families. The hierarchy is designed to categorize organisms in a logical and consistent manner. The other options are not accurate criteria for determining the taxonomic levels.

Question 9

-In the phylogenetic trees above,numbers represent species and the same species are shown in both trees.Which two species are represented as sister species in Tree 2 but are not shown as sister species in Tree 1?

Accepted Answer

In Tree 2, species 3 and 4 are shown as sister species, meaning they share a more recent common ancestor with each other than with any other species. However, in Tree 1, species 3 and 4 are not depicted as sister species, indicating a different evolutionary relationship.

Question 10

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

Accepted Answer

The legless condition has arisen independently in several groups of extant reptiles, such as snakes and some lizards. This suggests that the evolution of leglessness in these groups was not the result of a common ancestor having been legless or a shared adaptation to a specific lifestyle, but rather a result of convergent evolution.

Question 11

The domestic dog,red fox,and wolf belong to the family Canidae.The dog is Canis lupus familiaris,the red fox is Vulpes vulpes,and the wolf is Canis lupus.Which of the following statements is correct?

Accepted Answer

The red fox is in the same family as wolves and dogs (Canidae), but belongs to a different genus (Vulpes) than wolves and dogs (Canis).

Question 12

Which individual would make the worst systematist? One who is uncomfortable with the

Accepted Answer

The answer of Which individual would make the worst systematist?...

Question 13

Which of the following pairs are the best examples of homologous structures?

Accepted Answer

Bones in the bat wing and bones in the human forelimb are the best examples of homologous structures because they have a similar bone structure, despite having different functions. They both have a humerus, radius, and ulna, and similar arrangements of carpals, metacarpals, and phalanges.

Question 14

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?

Accepted Answer

Organisms D and F are in the same order and thus would be expected to have a higher degree of structural homology than organisms in different orders. Therefore, choice E, which pairs organisms D and F, would be expected to show the greatest degree of structural homology.

Question 15

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

Accepted Answer

Homoplasy refers to the independent evolution of similar features in different lineages, often as the result of convergent evolution. The legless condition found in various lineages of extant lizards is an example of homoplasy because the trait has evolved independently in different groups of lizards. The other options (B, C, D, and E) are not examples of homoplasy because they involve shared traits that are either inherited from a common ancestor (B, C, and D) or the result of divergent evolution (E).

Question 16

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

Accepted Answer

The use of computers and computer software has greatly facilitated analysis of molecular genetic data, which is now the primary method for reconstructing evolutionary relationships (cladistics) among organisms.

Question 17

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

The four-chambered hearts of birds and mammals are best described as homoplasies, which means they are similar structures that evolved independently in the two lineages after their divergence from a common ancestor with a three-chambered heart. This is not due to direct inheritance from a common ancestor with a four-chambered heart (which would be shared ancestry), but rather convergent evolution where similar environmental pressures led to the development of similar structures.

Question 18

Some molecular data place the giant panda in the bear family (Ursidae)but place the lesser panda in the raccoon family (Procyonidae).If the molecular data best reflect the evolutionary history of these two groups,then the morphological similarities of these two species is most likely due to

Accepted Answer

Possession of analogous (convergent) traits means that the two species evolved similar physical features due to adapting to similar environments or ecological niches, rather than a shared evolutionary history. This is likely the reason why the giant panda and the lesser panda have similar morphological features despite belonging to different families according to molecular data.

Question 19

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

Accepted Answer

One-base substitution is the mutation that should least require realignment of homologous regions of a gene. Substitution involves replacing one base with another, which changes one codon in the DNA sequence, but it does not change the reading frame of the gene. In contrast, insertions and deletions shift the reading frame and can cause significant changes in the protein sequence. Therefore, they are more likely to require realignment of homologous regions of the gene. A one-base deletion or three-base deletion also shift the reading frame and may result in a frameshift mutation that alters the amino acid sequence downstream of the mutation, potentially affecting protein function.

Question 20

Binomial nomenclature was devised by Carolus Linnaeus in the 18th century.Which of the following scientific names is written correctly?

Accepted Answer

The answer of Binomial nomenclature was devised by Carolus Linnaeus...

Quiz 26: Phylogeny and the Tree of Life