Topic 4

Question 1

What is systematics?

Answer 1

The theory (and practice) of classifying organisms based on evolutionary history

Question 2

What term describes the evolutionary history of a species or group of related species?

Answer 2

Phylogeny

Question 3

What are phylogenetic trees?

Answer 3

Diagrams that show hypotheses of the evolutionary relationship between organisms

Question 4

What is a taxa?

Answer 4

A set of organisms (or group of organisms)

Question 5

What does a branch point represent in a phylogenetic tree?

Answer 5

Each branch point or node represents the divergence of two species (speciation)

Question 6

Two descendants that split from the same node are called?

Answer 6

Sister taxa

Question 7

What is a basal taxon?

Answer 7

An outgroup that diverges early in the history of a group and originates near the common ancestor of the group

Question 8

A branch from which more than two groups emerge is a?

Answer 8

Polytomy

Question 9

A group of taxa that includes an ancestor and all descendants of that ancestor is a?

Answer 9

Clade

Question 10

What are the two types of phylogenetic trees?

Answer 10

Cladograms and phylograms

Question 11

What is a cladogram?

Answer 11

They depict evolutionary relationships where only branch order is important

Question 12

What is a phylogram?

Answer 12

They depict evolutionary patterns but branch lengths are proportional to evolutionary change

Question 13

T/F: The order of terminal taxa matters in the relatedness of taxa

Answer 13

False

Question 14

T/F: Phylogenetic trees show evolutionary relationships, not evolutionary progress

Answer 14

True

Question 15

What do phylogenetic polytomies indicate?

Answer 15

Lack of knowledge and rapid speciation

Question 16

What is an ingroup?

Answer 16

The group of taxa whose relationships you are interested in determining

Question 17

What do you call anatomical, physiological, or molecular features that make up organisms? What is an example of one?

Answer 17

Characters

Ex. DNA sequence

Question 18

What is state?

Answer 18

The observed manifestation of a character

Ex. arrangement of petals

Question 19

T/F: Characters that are similar because of descent from a common ancestor are said to be analogous

Answer 19

False

Homologous

Question 20

Similarities due to independent adaptation by different species are said to be:

Answer 20

Analogous

Question 21

Convergent evolution is?

Answer 21

Analogous character states appear the same but actually evolved independently

Question 22

How does convergent evolution occur?

Answer 22

Occurs when similar environmental pressures and natural selection produces similar adaptations in organisms from different evolutionary lineages

Question 23

Analogous structures or molecular sequences that evolved independently are called:

Answer 23

Homoplasies

Question 24

What is the method of inferring phylogeny from homologous characters?

Answer 24

Cladistics

Question 25

A valid clade is _ if it consists of an ancestor taxa and all its descendants and no other unrelated taxa

Answer 25

Monophyletic

Question 26

A _ grouping consists of an ancestral taxon, but not all of the descendants

Answer 26

Paraphyletic

Question 27

A _ grouping includes distantly related taxa but does not include the common ancestor of all group members

Answer 27

Polyphyletic

Question 28

Choosing the phylogeny that requires the fewest number of evolutionary events is called:

Answer 28

Parsimony (Occam’s Razor)

Question 29

Another word for a shared derived character is:

Answer 29

Synapomorphy

Question 30

Another word for a shared ancestral character is:

Answer 30

Symplesiomorphy