Chapter 20

Question 1

what are systematics?

Answer 1

the study of evolutionary relationships

Question 2

what is phylogeny?

Answer 2

organism’s evolutionary history and its relationships

Question 3

what is a phylogenetic tree?

Answer 3

a visual depiction of phylogeny

Question 4

is phylogeny fact?

Answer 4

no, it’s a hypothesis

Question 5

what are the three domains?

Answer 5

bacteriae, archea, eukarya

Question 6

what is the root in a phylogenetic tree?

Answer 6

ancestral lineage giving rise to all organisms on the tree

Question 7

what is the branch point in a phylogenetic tree?

Answer 7

where two lineages diverged

Question 8

what is the basal taxon in a phylogenetic tree?

Answer 8

lineage that evolved early and remains unbranched

Question 9

what are sister taxa in a phylogenetic tree?

Answer 9

two lineages stem from the same branch point

Question 10

what is a polytomy in a phylogenetic tree?

Answer 10

a branch with more than two lineages

Question 11

what do phylogenies depict?

Answer 11

evolutionary relationships

Question 12

how are phylogenetic trees structured when they are based on the presence of shared characteristics?

Answer 12

yes/no equals separation, with the yes branch point continuing up the tree

Question 13

why is binomial nomenclature in latin?

Answer 13

it’s a dead, universal language that won’t change

Question 14

what is the most inclusive classification?

Answer 14

domain

Question 15

what is the most specific classification that is always present?

Answer 15

species

Question 16

what is an even more specific classification than species but isn’t always present, and has 3 names instead of just 2?

Answer 16

subspecies

Question 17

what are shared derived characteristics? give an example

Answer 17

similarity that is inherited from the MOST RECENT common ancestor of an entire group, like fur in the class mammalia

Question 18

what are ancestral shared characteristics? give an example

Answer 18

similarity that arose PRIOR TO the common ancestor of the group, like the vertebral column in the class mammalia

Question 19

what kind of characteristics are considered informative about evolutionary relationships?

Answer 19

shared derived characteristics

Question 20

what can be classified as a character?

Answer 20

any part of the phenotype, like morphology, behavior, physiology, DNA

Question 21

how should characters exist?

Answer 21

in recognizable states, like presence or absence of character

Question 22

what kind of characteristic is presence of hair in mammals?

Answer 22

shared derived characteristic

Question 23

what kind of characteristic is presence of lungs in mammals and why?

Answer 23

ancestral feature, it is also present in amphibians and reptiles

Question 24

what happens to shared derived characteristics as you move further up a cladogram/phylogenetic tree?

Answer 24

they become ancestral characteristics as more branch points form and evolution takes place

Question 25

what kind of characteristic is presence of teeth in mammals and reptiles?

Answer 25

ancestral

Question 26

what kind of characteristic is absence of teeth in birds and turtles?

Answer 26

shared derived

Question 27

what is a clade?

Answer 27

species that share a common ancestor as indicated by the presence of SHARED DERIVED characteristics

Question 28

how are clades used when creating a phylogenetic tree?

Answer 28

as evolutionary units

Question 29

what do clades refer to in a phylogenetic tree?

Answer 29

a common ancestor and all descendants

Question 30

what does a clade include in a phylogenetic tree?

Answer 30

all descendants from a particular branch point

Question 31

clades can vary in size based on what?

Answer 31

which branch point is referred

Question 32

are clades separate units?

Answer 32

no, one clade can be nested in another

Question 33

what is a taxon?

Answer 33

refers to a named taxonomic unit at any given level of classification

Question 34

what is a monopyhletic group, where is it located on a phylogenetic tree, and what does it include?

Answer 34

synonomous with clade, from a single branch point, includes an ancestral species and ALL of its descendants

Question 35

give an example of a clade?

Answer 35

clade amniota

Question 36

what is a paraphyletic group?

Answer 36

consists of ancestral species and some BUT NOT ALL of its descendants

Question 37

what is a polyphyletic group?

Answer 37

consists of a grouping of species but DOES NOT include the most recent common ancestor

Question 38

are species within polyphyletic groups closely related?

Answer 38

not necessarily

Question 39

what is an outgroup?

Answer 39

a species/group from an evolutionary line that is closely related to but not part of the group of interest (ingroup), like a basal taxon

Question 40

what does the most parsimonious phylogenetic tree require?

Answer 40

the fewest evolutionary events