Lect 6- Phylogenies Flashcards Preview

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Flashcards in Lect 6- Phylogenies Deck (18):
1

Phylogenetic Principle Vs. Phenetic Principle

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

2

Phylogeny

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

3

Clade

group that includes common ancestor and it's descendants

4

Styles of phylogenies

tree, ladder, circular

5

Terminal vs Interior Nodes

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

6

Sister groups and out group

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

7

Polotomy

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)

8

Rooted Vs. Unrooted Phylogeny

unrooted- shows relationships but not ancestral

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

9

Evidence Traits for Phylogenies

observable characteristics of orgs
-anatomical feat
-physiological
-developmental
-behavior pattern
-genetic sequence

10

Homology

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

11

Homoplasy

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

12

Analogus

similar in function but in structure or evo origin

13

Evolutionary divergence

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

14

Synapomorphy

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)

15

Monophyletic Group

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

16

Paraphyletic Group

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

17

Symplesiomorphy

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

18

Polyphyletic Group

group does not contain common ancestor of its members
ex: homeotherms- consist of birds and mammals but not a common ancestor