Chapter 26: Phylogeny and the Tree of Life

Question 1

Phylogeny

Answer 1

Evolutionary history of a species or group of related species

Question 2

Systematics

Answer 2

Discipline focused on classifying organisms and determining their evolutionary relationships

Question 3

Taxonomy

Answer 3

Scientific discipline where organisms are named and classified

Question 4

Binomial Nomenclature

Answer 4

• 2 part format of an organism’s scientific name

- Instituted by Charles Linnaeus

Question 5

Genus

Answer 5

First part of scientific name

Question 6

Order of Classification

Answer 6

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 7

Taxon

Answer 7

A named taxonomic unit at any level of classification

Question 8

Phylogenetic Tree

Answer 8

Branching diagram that shows evolutionary history of a group of organisms

Question 9

Branch Points

Answer 9

The representation on a phylogenetic tree of the divergence of two or more taxa from a common ancestor

Question 10

Sister Taxa

Answer 10

Groups of organisms that share an immediate common ancestor and hence are each other’s closest relatives

Question 11

Rooted

Answer 11

A branch point within the tree represents the most recent common ancestor of all taxa in the tree

Question 12

Basal Taxon

Answer 12

• A lineage that diverged early in the history of a group

- Lies on a branch near the common ancestor of the groups

Question 13

Polytonomy

Answer 13

A branch point from which > two descendant groups emerge

Question 14

Analogy

Answer 14

Similarity between two organisms due to convergent evolution

Question 15

Homoplasies

Answer 15

Analogous structures that evolved separately

Question 16

Cladistics

Answer 16

Approach to systematics where common ancestry is the primary criteria used to classify organisms

Question 17

Clades

Answer 17

Groups that include a species and its descendants

Question 18

Monophyletic

Answer 18

Consists of an ancestral species and all of its descendants

Question 19

Paraphyletic

Answer 19

Contains ancestral species and some of its descendants

Question 20

Polyphyletic

Answer 20

Includes distantly related species but not the most recent common ancestor

Question 21

Shared Ancestral Character

Answer 21

Character that originated in the ancestor of the taxon

Question 22

Shared Derived Character

Answer 22

An evolutionary novelty that is unique to a particular clade

Question 23

Outgroup

Answer 23

Species / group of species from an evolutionary lineage that is known to have diverged before

Question 24

Ingroup

Answer 24

The lineage that includes the species being studied

Question 25

Maximum Parsimony (Occam’s Razor)

Answer 25

The simplest explanation that is consistent with the facts should be investigated first

Question 26

Maximum Likelihood

Answer 26

The tree most likely to have produced a given set of DNA data is identified based on certain probability rules about how DNA sequences change over time

Question 27

Orthologous Genes

Answer 27

Homology is the result of a specific speciation event and occurs between genes in different species

Question 28

Paralogous Genes

Answer 28

• Homology results from gene duplication

- Multiple copies of these genes have diverged from one another within a species

Question 29

Molecular Clock

Answer 29

Approach for measuring the absolute time of evolutionary change based on the observation that some genes and other regions of genomes appear to evolve at constant rates

Question 30

Horizontal Gene Transfer

Answer 30

The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms