The Tree of Life and The History of Life

Question 1

Tree of Life

Answer 1

-phylogenies show evolutionary relationships

-phylogenies are inferred from morphological and molecular data

-shared characters are used to construct phylogenetic trees

Question 2

History of Life

Answer 2

-conditions on early earth made the origin of life possible

-the fossil record documents the history of life

-key events in life’s history: the origin of unicellular and multicellular life, and the colonization of land

-the rise and fall of major groups of organisms are caused by extinction and radiation

Question 3

Phylogenetic tree

Answer 3

branching diagram that represents a hypothesis about the evolutionary history of a group of organisms

Question 4

Root

Answer 4

represents ancestral lineage

Question 5

Branch tips

Answer 5

represents the most recent descendants of that ancestor

Question 6

Evolutionary lineage

Answer 6

a sequence of ancestral organisms leading to a particular descendant taxon

Question 7

Branch point (node)

Answer 7

represents a common ancestor and the divergence of two evolutionary lineages from that common ancestor

Question 8

Common ancestor

Answer 8

an ancestral population that gave rise to two or more descendant lineages

Question 9

Most recent common ancestor

Answer 9

youngest relative from which all the linages in the group are directly descended

Question 10

Clade

Answer 10

a grouping that includes a common ancestor and all the descendants of that ancestor; also called monophyletic groups

Question 11

Paraphyletic group

Answer 11

consists of some but not all of the descendants of an ancestral species

Question 12

Polyphyletic group

Answer 12

includes distantly related species but does not include their most recent common ancestor

Question 13

Sister taxa

Answer 13

groups that share a common ancestor that is not shared by any other group; more closely related to each other than any other taxon

Question 14

Systematics

Answer 14

a discipline focused on classifying organisms and determining their evolutionary relationships

Question 15

Organisms have to have what to be more closely related?

Answer 15

Similar phenotypes or similar DNA sequences

Question 16

Characters

Answer 16

phenotypic traits

Question 17

Shared ancestral character

Answer 17

a character that originated in an ancestor of the taxon

Question 18

Shared derived character

Answer 18

an evolutionary novelty unique to a particular clade

Question 19

Homology

Answer 19

shared ancestry

Question 20

Analogy

Answer 20

similar through convergent evolution

Question 21

Outgroup

Answer 21

a species or group of species closely related to, but not part of the group of species being studied

Question 22

Ingroup

Answer 22

the group of species being studied

Question 23

An ancestral character is present in…

Answer 23

both the outgroup and the ingroup

Question 24

A derived character is present in…

Answer 24

only the ingroup

Question 25

Maximum parismony

Answer 25

assumes that the most likely tree is the one that requires the fewest evolutionary events (appearances of shared derived characters)

Question 26

Extant

Answer 26

still in existence; surviving

Question 27

Convergent evolution

Answer 27

evolution of similar features in independent evolutionary lineages