Phylogenetic Systematics

Question 1

Systematics

Answer 1

study of the kinds of organisms and of the evolutionary relationships
-goal: to classify organisms naturally, so the various groups are meaningful

Question 2

Taxonomy

Answer 2

Science of classification

Kingdom > phylum > class > order > Family > genus > species

Question 3

Cladistics

Answer 3

method of inferring genealogy and classifying organisms exclusively on the basis of shared, derived, traits > Synapomorphy

Question 4

Homology

Answer 4

similarity of a feature in different organisms due to shared ancestry

Question 5

Homoplasy

Answer 5

similarity of a feature not due to a shared ancestry

Question 6

Character

Answer 6

observable feature of an organism

Question 7

Character polarity

Answer 7

order in which evo changes occurred

Question 8

Synapomorphy

Answer 8

shared derived character

Question 9

Plesiomorphy

Answer 9

shared ancestral character

Question 10

Autapomorphy

Answer 10

derived character possessed by only one taxon on a tree

Question 11

Character States

Answer 11

• Binary Character: Only two character states (Present or absent)
• Multistate Character: three or more states
• Missing data: character unobservable or unknown

Question 12

Principle of Parsimony

Answer 12

-Simplest hypothesis is preferred

Question 13

Tree Length

Answer 13

Minimum # of characters state transitions

Question 14

Outgroup Comparison

Answer 14

taxon that are related to your study taxa, but do not fall within that group

Question 15

Stratigraphic criterion

Answer 15

root placed on the taxon that appears earliest in the fossil record

Question 16

Polytomy

Answer 16

representation of multiple equally probable relationships

Question 17

Strict Consensus Tree

Answer 17

a way of summarizing multiple MPTs

Question 18

Clad

Answer 18

an ancestor and all of its descendants

Question 19

paraphyletic group

Answer 19

doesn’t contain all descendants of a given ancestor

Question 20

Polyphyletic group

Answer 20

contains descendants from more than one immediate ancestor

Question 21

Phylogenetic Systematics

Answer 21

devoloped by Willi Hennig

Question 22

Search algorithms: Branch and Bound

Answer 22

• counts tree length as it is building tree
• finds exact solution, but doesn’t bother finishing construction of all trees
• only works for up to 25 taxa

Question 23

Search Algorithms: Heuristic Search

Answer 23

• builds tree counts steps
• rearranges tree until shortest one found
• not guaranteed to find all MPTs

Question 24

Consistency index

Answer 24

measure of homoplasy in characters

Question 25

Hierarchy of Certainty

Answer 25

(Most to least)

1. direct/indirect preservation, 2) phylogenetic bracketing 3) modern analogy 4) Speculation

Question 26

Ghost lineage/Range extensions

Answer 26

Ghost: unsampled extention of the expected fossil record of a clade
Range: unsampled extension of the expected fossil record of a taxon