Question 1

Analyses of molecular sequences for study of evolutionary relationships are constrained by ____.

Accepted Answer

The limited number of nucleotide characters can make it challenging to discern whether genetic similarities between species are due to convergent evolution (homoplasy) or shared ancestry (homology), thus constraining molecular sequence analyses in evolutionary studies.

Question 2

The principle of parsimony ____ for constructing the phylogenetic tree that represents the smallest number of evolutionary changes.

Accepted Answer

The principle of parsimony aims to minimize the number of homoplasies, which are traits that have arisen independently in different lineages, thus favoring the simplest explanation or path of evolutionary changes.

Question 3

Influencing the philosophy and analysis of many systematists in the mid-1900s, ____ published Phylogenetic Systematics , arguing that classifications should be based solely on evolutionary relationships.

Accepted Answer

Willi Hennig is credited with founding the field of phylogenetic systematics, also known as cladistics, through his publication "Phylogenetic Systematics" where he argued that classifications should reflect evolutionary relationships.

Question 4

With cladistic analyses, characters of an organism exist in ____ form(s), referred to as ____.

Accepted Answer

In cladistic analyses, characters of an organism are considered in two forms, known as character states. These states are used to determine evolutionary relationships by comparing shared characteristics among different organisms.

Question 5

Crocodilians are classified as reptiles; however, they share a common ancestor with birds, which are not classified as reptiles. Therefore, Reptilia is a ____ taxon.

Accepted Answer

Reptilia is considered a paraphyletic group because it includes some but not all of the descendants of their most recent common ancestor. Since birds are descended from within the group that includes reptiles but are not classified as reptiles themselves, the group excludes some descendants (birds) of their common ancestor, making it paraphyletic.

Question 6

In the absence of evidence from fossils, systematists frequently use a technique called ____ to identify ancestral and derived character states.

Accepted Answer

Outgroup comparison is a method used by systematists to identify ancestral and derived character states when fossil evidence is not available. This technique involves comparing the characteristics of the group of interest (ingroup) with those of one or more closely related groups outside of it (outgroups) to infer which characteristics are ancestral.

Question 7

Which innovation(s) places birds in a separate class?

Accepted Answer

Birds are distinguished by their combination of wings, flight capability, and high metabolic rate. While other animals may have one or two of these characteristics, the combination of all three is unique to birds.

Question 8

The PhyloCode is a set of rules for ____.

Accepted Answer

The PhyloCode is designed specifically for identifying and naming clades, which are groups of organisms that include a common ancestor and all its descendants. This system focuses on relationships and ancestry rather than traditional taxonomic ranks.

Question 9

The polymerase chain reaction (PCR) has advanced our understanding of systematics because it allows for ____.

Accepted Answer

PCR enables the amplification of small DNA fragments, allowing scientists to analyze genetic material from limited or degraded samples, such as those found in museum specimens and fossils. This has significantly advanced the field of systematics by providing genetic data where it was previously unobtainable.

Question 10

When systematists compare vertebrates to all other animals, the absence of a vertebral column is the ____ character state, and the presence of a vertebral column is the ____.

Accepted Answer

The absence of a vertebral column is considered the ancestral character state because it is the original state present in the common ancestor of vertebrates and other animals. The presence of a vertebral column is the derived character state, indicating it evolved later in the lineage leading to vertebrates.

Question 11

The scientific approach that classifies organisms based on evolutionary relationships is known as ____.

Accepted Answer

Cladistics is the scientific approach that focuses on classifying organisms based on their evolutionary relationships, using shared derived characteristics to infer the evolutionary history and relationships among groups.

Question 12

Turtles, lizards, snakes, crocodilians, and birds descended most recently from an ancestral ____.

Accepted Answer

The answer of Turtles, lizards, snakes, crocodilians, and birds descended...

Question 13

Because ____ character states are shared by the ingroup and the outgroup, phylogenetic trees are constructed by cladistic analyses that group species that share only ____ character states.

Accepted Answer

Ancestral character states are shared by both the ingroup and the outgroup, while derived character states are unique to the ingroup and used to construct phylogenetic trees in cladistic analyses.

Question 14

According to cladistics, a derived character state is called a(n) ____.

Accepted Answer

An apomorphy refers to a derived character state that is unique to a particular species or group, distinguishing it from its ancestors and other groups. This is a key concept in cladistics for identifying evolutionary relationships.

Question 15

Comparison of the wings of birds and the wings of bats reveals that they____.

Accepted Answer

Bird and bat wings are analogous as structures because they serve similar functions (flight) but are not derived from a common ancestral wing structure, making them homoplastic. However, they also have homologous components, such as the bones in their wings, which are derived from common ancestral forelimbs, thus sharing an evolutionary origin.

Question 16

Fossils of plants found in deeper geologic layers do not show vascular tissues, while fossils in shallower geologic layers include some specimens with and some without vascular tissues. Thus, vascular tissue in plants is considered a ____ character.

Accepted Answer

Derived characters are traits that appear in later organisms but not in earlier ones. The presence of vascular tissues in plants in shallower (more recent) geologic layers, but not in deeper (older) layers, indicates that vascular tissues are a derived character, having evolved later in the history of plant life.

Question 17

Unless a derived character state is lost or replaced by newer characters over evolutionary time, ____ can serve as markers for ____ lineages that underwent adaptive radiation.

Accepted Answer

Synapomorphies are derived character states shared by a group of organisms, indicating a common ancestry. They can serve as markers for monophyletic lineages, which include an ancestral species and all its descendants, and are often identified through adaptive radiation.

Question 18

Phenotypic similarities that provide no information about shared ancestry because they are not inherited from a common ancestor are ____.

Accepted Answer

Homoplasies refer to phenotypic similarities that do not arise from shared ancestry but rather from convergent evolution or parallel evolution, where different species independently evolve similar traits.

Question 19

An ancestral ____ gave rise to animals including mammals, lizards, turtles, and birds.

Accepted Answer

The ancestral amniote is the common ancestor that gave rise to various groups of animals, including mammals, lizards, turtles, and birds, characterized by their ability to lay eggs on land or retain them within the body.

Question 20

The closest living relatives of birds are ____.

Accepted Answer

The closest living relatives of birds are crocodiles. Both birds and crocodiles are part of the Archosauria group, which also included the now-extinct dinosaurs. Genetic and fossil evidence supports this close relationship.

Quiz 24: Systematic Biology: Phylogeny and Classification

Analyses of molecular sequences for study of evolutionary relationships are constrained by ____.

The principle of parsimony ____ for constructing the phylogenetic tree that represents the smallest number of evolutionary changes.

Influencing the philosophy and analysis of many systematists in the mid-1900s, ____ published Phylogenetic Systematics , arguing that classifications should be based solely on evolutionary relationships.

With cladistic analyses, characters of an organism exist in form(s) , referred to as .

Crocodilians are classified as reptiles; however, they share a common ancestor with birds, which are not classified as reptiles. Therefore, Reptilia is a ____ taxon.

In the absence of evidence from fossils, systematists frequently use a technique called ____ to identify ancestral and derived character states.

Which innovation(s) places birds in a separate class?

The PhyloCode is a set of rules for ____.

The polymerase chain reaction (PCR) has advanced our understanding of systematics because it allows for ____.

When systematists compare vertebrates to all other animals, the absence of a vertebral column is the character state, and the presence of a vertebral column is the .

The scientific approach that classifies organisms based on evolutionary relationships is known as ____.

Turtles, lizards, snakes, crocodilians, and birds descended most recently from an ancestral ____.

Because character states are shared by the ingroup and the outgroup, phylogenetic trees are constructed by cladistic analyses that group species that share only character states.

According to cladistics, a derived character state is called a(n) ____.

Comparison of the wings of birds and the wings of bats reveals that they____.

Fossils of plants found in deeper geologic layers do not show vascular tissues, while fossils in shallower geologic layers include some specimens with and some without vascular tissues. Thus, vascular tissue in plants is considered a ____ character.

Unless a derived character state is lost or replaced by newer characters over evolutionary time, can serve as markers for lineages that underwent adaptive radiation.

Phenotypic similarities that provide no information about shared ancestry because they are not inherited from a common ancestor are ____.

An ancestral ____ gave rise to animals including mammals, lizards, turtles, and birds.

The closest living relatives of birds are ____.

Quiz 24: Systematic Biology: Phylogeny and Classification

Analyses of molecular sequences for study of evolutionary relationships are constrained by ____.

The principle of parsimony ____ for constructing the phylogenetic tree that represents the smallest number of evolutionary changes.

Influencing the philosophy and analysis of many systematists in the mid-1900s, ____ published Phylogenetic Systematics , arguing that classifications should be based solely on evolutionary relationships.

With cladistic analyses, characters of an organism exist in ____ form(s) , referred to as ____.

Crocodilians are classified as reptiles; however, they share a common ancestor with birds, which are not classified as reptiles. Therefore, Reptilia is a ____ taxon.

In the absence of evidence from fossils, systematists frequently use a technique called ____ to identify ancestral and derived character states.

Which innovation(s) places birds in a separate class?

The PhyloCode is a set of rules for ____.

The polymerase chain reaction (PCR) has advanced our understanding of systematics because it allows for ____.

When systematists compare vertebrates to all other animals, the absence of a vertebral column is the ____ character state, and the presence of a vertebral column is the ____.

The scientific approach that classifies organisms based on evolutionary relationships is known as ____.

Turtles, lizards, snakes, crocodilians, and birds descended most recently from an ancestral ____.

Because ____ character states are shared by the ingroup and the outgroup, phylogenetic trees are constructed by cladistic analyses that group species that share only ____ character states.

According to cladistics, a derived character state is called a(n) ____.

Comparison of the wings of birds and the wings of bats reveals that they____.

Fossils of plants found in deeper geologic layers do not show vascular tissues, while fossils in shallower geologic layers include some specimens with and some without vascular tissues. Thus, vascular tissue in plants is considered a ____ character.

Unless a derived character state is lost or replaced by newer characters over evolutionary time, ____ can serve as markers for ____ lineages that underwent adaptive radiation.

Phenotypic similarities that provide no information about shared ancestry because they are not inherited from a common ancestor are ____.

An ancestral ____ gave rise to animals including mammals, lizards, turtles, and birds.

The closest living relatives of birds are ____.

With cladistic analyses, characters of an organism exist in form(s) , referred to as .

When systematists compare vertebrates to all other animals, the absence of a vertebral column is the character state, and the presence of a vertebral column is the .

Because character states are shared by the ingroup and the outgroup, phylogenetic trees are constructed by cladistic analyses that group species that share only character states.

Unless a derived character state is lost or replaced by newer characters over evolutionary time, can serve as markers for lineages that underwent adaptive radiation.