Lect 6- Phylogenies

Question 1

Phylogenetic Principle Vs. Phenetic Principle

Answer 1

Phylogenetic: evolutionary relatedness by more recent common ancestor
ex: bird and dino more closely related than lizzard

Phenetic: spp are grouped by similarities (often morphologies)
ex: dino more similar to lizzard than to bird

Question 2

Phylogeny

Answer 2

branching relationships of populations as they give rise to multiple descendant populations over time

Question 3

Clade

Answer 3

group that includes common ancestor and it’s descendants

Question 4

Styles of phylogenies

Answer 4

tree, ladder, circular

Question 5

Terminal vs Interior Nodes

Answer 5

on a phylogeny TN represent observed organisms and IN represent hypothetical ancestors that are inferred

Question 6

Sister groups and out group

Answer 6

on phylogeny,
SG taxa derived from same node
Out group is related to other taxa but branched off earlier

Question 7

Polotomy

Answer 7

on phylogeny,
node with two or more taxa arising from it, usually to represent uncertainty about phylogenic relationship
(may show multiple speciation but less common)

Question 8

Rooted Vs. Unrooted Phylogeny

Answer 8

unrooted- shows relationships but not ancestral

rooted- shows relationships and has an out group to show more ancestral info

Question 9

Evidence Traits for Phylogenies

Answer 9

observable characteristics of orgs

• anatomical feat
• physiological
• developmental
• behavior pattern
• genetic sequence

Question 10

Homology

Answer 10

Similarity of train in two or more spp which indicates decent from a common ancestor
ex: hypothesis- forelimbs in whales, horses, falcons and bats are homologous

Question 11

Homoplasy

Answer 11

Trait similar in two taxa b/c of convergent evo and not common ancestory

ex: sugar gliders and flying squirrles (fingers and legs with membrane for gliding) distantly related and independently evolved feature
ex: flippers in dolphins and manatee- common ancestor had no flippers

Question 12

Analogus

Answer 12

similar in function but in structure or evo origin

Question 13

Evolutionary divergence

Answer 13

related spp no longer resemble each other bc evo has adapted them to different ecological conditions
ex: manatee flippers and elephant trunk but have common ancestor who had neither

Question 14

Synapomorphy

Answer 14

a characteristic present in an ancestral species and shared exclusively (in more or less modified form) by its evolutionary descendants.
possession by two or more organisms of a characteristic inherited exclusively from their common ancestor.
ex: amniotes (tetrapod vertabrates - reptiles, birds, mammals- which lay eggs on land or keep in body. (amnion- membrane fetus)

Question 15

Monophyletic Group

Answer 15

group consisting of all descendants of the group’s most recent common ancestor and no other members

Question 16

Paraphyletic Group

Answer 16

group of organisms that includes an ancestor but not all of its descendants.
ex: reptiles are ectotherms but birds are endothems and left out of the group though their common ancestor was ectothermic

Question 17

Symplesiomorphy

Answer 17

an ancestral character or trait state shared by two or more taxa.

Question 18

Polyphyletic Group

Answer 18

group does not contain common ancestor of its members

ex: homeotherms- consist of birds and mammals but not a common ancestor