Phylogenies

Question 1

Tip

Answer 1

Group of related organisms (any species, gene, order, category etc.)
-Tips can be broken down further & further

Question 2

Node

Answer 2

Branch point on a phylogenetic tree; representing an ancestor
-can rotate nodes; CANNOT change sister group

Question 3

Root

Answer 3

Most ancestral lineage on a phylogenetic tree

Question 4

Unrooted

Answer 4

Not sure where root should go

Question 5

Ingroup

Answer 5

The clade of focus of a phylogenetic tree

Question 6

Outgroup

Answer 6

Distantly related group with a known relationship to the taxon studied

Question 7

Clade

Answer 7

A group of organisms that are monophyletic- that is, composed of a common ancestor and all its lineal descendants- on a phylogenetic tree

Question 8

Monophyletic

Answer 8

Group that concludes the common ancestor and all the descendants

Question 9

Paraphyletic

Answer 9

A group that includes the common ancestor but not all the descendants

Question 10

Polyphyletic

Answer 10

A group that includes the descendants but not the common ancestor

Question 11

Sister taxa

Answer 11

2+ groups immediately derived from a common ancestor

Question 12

Character

Answer 12

Feature in an organism (genetic, morphological, behavioral, physiological)

Question 13

Trait

Answer 13

Form of a character (ex. Color, swims in water)
-more specific than characters

Question 14

Synapomorphy

Answer 14

Derived trait shared by 2 (or more taxa)

Question 15

Sympleisiomorphy

Answer 15

Shared ancestral trait

Question 16

Homoplasy

Answer 16

Trait shared by 2 or more taxa but not by their common ancestor

Question 17

Homology

Answer 17

Trait shared by 2 organisms because their common ancestor had that trait

Question 18

Analogous Trait

Answer 18

Trait shared by 2 organisms because of similar environmental pressures

Question 19

Phylogeny

Answer 19

Branching relationships of populations as they give rise to multiple descendent populations over evolutionary time

Question 20

Phylogram

Answer 20

Phylogenetic tree in which the length of each branch represents the amount of evolutionary change that has occurred along that branch

Question 21

Chronogram

Answer 21

Phylogenetic tree on which absolute time is denoted
-gives actual time period

Question 22

How do you determine if a group is monophyletic, paraphyletic, or polyphyletic?

Answer 22

-A group is MONOPHYLETIC when the group includes the common ancestor and all the descendants
-A group that is PARAPHYLETIC is a group that includes the common ancestor but not all the descendants
-A group that is POLYPHYLETIC is a group that includes the descendants but not the common ancestor

Question 23

Compare phylogram, chronogram, and phylogeny

Answer 23

-Phylogeny is the usual tree-like branching system we use
-Phylogram is similar to phylogeny but the length of each branch shows the amount of evolutionary change that has occurred
-Chronogram is a phylogenetic tree where actual time period is shown

Question 24

How to identify if a trait is synapomorphy, sympleisiomorphy, homoplasious, homologous, or analogous?

Answer 24

-A trait that is SYNAPOMORPHY is a derived trait shared by two or more taxa (will see the trait more recently with a common ancestor)
-A trait that is SYMPLEISIOMORPHY is a shared ancestral trait (will see the trait with latest ancestor)
-A trait that is HOMOPLASIOUS will be a trait shared by 2 or more taxa but not by the common ancestor (trait evolved with no ancestor similarity)
-A trait that is HOMOLOGOUS is a trait that is shared by 2 organisms because their common ancestor had that trait (organisms have the trait because recent ancestor had it)
-A trait that is ANALOGOUS is a trait that is shared by 2 organisms because of similar environmental pressures (hovering to feed in butterflies and hummingbird)

Question 25

Derived Trait

Answer 25

Traits that just appeared (by mutation) in the most recent ancestor