Chapter 26.1 Phylogeny and the Tree of Life

Question 1

PHYLOGENY

Answer 1

The evolutionary history of a species or group of related species.

Question 2

SYSTEMATICS

Answer 2

a discipline focused on classifying organisms and determining heir evolutionary relationships. Used by biologists to construct phylogenies.

Systematics use data ranging from fossils to molecules and genes to infer evolutionary relationships.

Question 3

TAXONOMY

Answer 3

Scientific discipline that names and classifies organisms

Question 4

BINOMIAL

Answer 4

Scientific naming (Genus species)

Question 5

TAXON

Answer 5

a group within one of the hierarchical classification ( e.g.. domain , kingdom, phylum, class, order ,family , genus, species) ( Panthera is a taxon at he genus level)

Question 6

HOMOLOGOUS STRUCTURES

Answer 6

structures in different species that are similar because of common ancestry

Question 7

A PHYLOGENIC TREE REPRESENTS

Answer 7

The evolutionary history of a group of organisms. it represents a hypothesis about an evolutionary relationship
These relationships are depicted as BRANCH POINTS
. shows patterns of descent, not phylogeny.

Question 8

BRANCH POINTS

Answer 8

depicts evolutionary relationships. Each branch point represents the divergence of two evolutionary lineage’s from a common ancestor.

Question 9

SISTER TAXA

Answer 9

groups of organisms that share an immediate common ancestor

Question 10

BASAL TAXON

Answer 10

refers to a lineage that diverges early in the history of a group. It lies on a branch that originates near the common ancestor of the group

Question 11

POLYTOMY

Answer 11

a branch point from which more than two descendant groups emerge. A polygamy signifies the evolutionary relationships among the taxa are not yet clear.

Question 12

EXTANT

Answer 12

living species

Question 13

The length of the branch point indicate what

Answer 13

time

Question 14

How are phylogenies inferred

Answer 14

from morphological and molecular data

. It is important to focus on features that result from common ancestry (homologies)

Question 15

HOMOLOGIES

Answer 15

phenotypic and genetic similarities due to a common ancestry. similar structures different functions

Question 16

ANALOGOUS

Answer 16

similarity due to convergent evolution. similar function different structure

Question 17

CONVERGENT EVOLUTION

Answer 17

occurs when similar environmental pressures and natural selection produce similar adaptations in organism from different evolutionary lineages

Question 18

HOMOPLASIES

Answer 18

analogous ( comparable) structures that arose independently

Question 19

ways to tell homology from analogy

Answer 19

. corroborative similarities
. fossil evidence
. the complexity of the characters being compared ( the more elements that are similar in two complex structures, the more likely it is that they evolved from a common ancestor) including genes=molecular homologies

Question 20

First 2 steps in reconstructing phylogenies

Answer 20

. distinguish homologous features from analogous ones ( since only homology reflect evolutionary history)
. then choose a method of inferring phylogeny from the homologous characters

Question 21

CLADISTICS

Answer 21

an approach to systematics where common ancestry is the primary criterion used to classify organisms

Question 22

CLADE

Answer 22

a group of species that includes an ancestral species and all of its descendants

Question 23

MONOPHYLETIC ( single tribe) ( a Clade)

Answer 23

a group that consists of an ancestral species and all of its descendants

Question 24

PARAPHYLETIC ( beside the tribe)

Answer 24

group which consists of an ancestral species and some but not all of its descendent

Question 25

POLYPHYLETIC

Answer 25

group which include members with different ancestors

Question 26

SHARED ANCESTRAL CHARACTER

Answer 26

A character that originated in an ancestor of the taxon

Question 27

SHARED DERIVED CHARACTER

Answer 27

character shared by all members but that did not originate in the ancestor. ( an evolutionary novelty unique to a clade.

Question 28

How are phylogenies inferred by using derived characters

Answer 28

Shared derived characters are unique to particular clades. It should be possible to determine the clade in which each shared derived character first appeared and use the information to infer evolutionary relationships

Question 29

OUTGROUP

Answer 29

used as a basis of comparison.
is a species are group of species from an evolutionary lineage that is known to have diverged before the lineage that includes the species we are studying ( INGROUP)

Question 30

Branch lengths are proportional to

Answer 30

the amount of evolutionary change or to the times at which a particular event occurred
. longer branches = in the time since 2 species diverged from a common ancestor more genetic changes have occurred in the lineage of a longer branch than that of a shorter branch
.

Question 31

the most Parsimonious tree

Answer 31

requires the fewest evolutionary events, as measured by the origin of shared derived morphological characters.