Character coding (clad Anal 2)

Question 1

What are the several
criteria to orientate character states?

Answer 1

• outgroup comparison
• ontogenetic criterion
• palaeontological criterion
• chorologic criterion

Question 2

uninformative
character

Answer 2

characters with only
autapomorphic transformations; present less than twice as derived character state
in group of interest (ingroup)

Question 3

in terms of Outgroup criterion, ingroup =

Answer 3

Polarity
among alternative character states within a
group of interest

Question 4

in terms of Outgroup criterion; Outgroup =

Answer 4

inferred from the distribution of character states in one or more additional taxa assumed to be outside of the group of interest

Question 5

Code a character based on this prop

Answer 5

note: The bottom one has multiple K states. This state can determine which is pleisio and which are derived (0 = pleisio, 1 and 2 are derived.)

Not necessary to code character states according to polarization, AKA not necessary to code supposed plesiomorphic states.

Character polarity can be deduced a posteriori from the
most parsimonious tree when using a rooting outgroup
(next section)

Question 6

character state is plesiomorphic if

Answer 6

one of two character states is present in both
ingroup and outgroup

Question 7

character state is apomorphic if

Answer 7

if the other character states are present only in ingroup

Question 8

To chose an outgroup you need to

Answer 8

choose one/several taxa external to studied group

one/several taxa used as a reference

one/several taxa closely related enough to ingroup

to make comparison of different character states between ingroup and outgroup

Question 9

Answer 9

Question 10

Answer 10

Question 11

Answer 11

Question 12

In terms of Ontogenetic Criterion,

Answer 12

transformation from one character observed to be more general to one character observed to be less general

the more general character plesiomorphic

and the less general character apomorphic

Question 13

In terms of this example, create a character-coding.

Answer 13

Question 14

In terms of paleontological criterion…

Answer 14

the more plesiomorphic of two alternative character states is the more ancient

stratigraphic position and other dating techniques
allows to determine the relative age of fossils

information used to infer plesiomorphic
character state based on occurrence in probably oldest fossils

valuable criterion when relationships between fossil taxa are quite close

the more plesiomorphic of the two alternative states is not systematically the more ancient

Question 15

Answer 15

Question 16

in terms of Chorologic Criterion, Chorology is the…..

Draw a representation.

Answer 16

study of the spatial distribution of
organisms;

Note: The more a taxa moves away from its center of origin the more its character states are derived The most derived character state appears in taxa which are separated from the initial taxon by the greatest geographical distance

Question 17

Different models of parsimony are according to what?

Answer 17

constraints on character transformations

constraints influence topology branch length and total number of trees

Question 18

Describe the Wagner Parsimony Model

Answer 18

Character states reversible ordered

Convergences: possible

A change from state 0 to state 2 costs 2 steps

more than a change from 0 to 1 (1 step)

and has the same cost as a change from 2 to 0

Basic application of parsimony principle on a set of data

Question 19

Describe the Fitch Parsimony Model

Answer 19

Character states: reversible unordered

Convergences: possible

all changes have equal cost

change from 0 to 1 change from 0 to 2 (1 step)

criterion with fewest assumptions

generally preferable

Question 20

Describe the Camin Sokal Parsimony Model

Answer 20

Character states not reversible

Convergences possible

Question 21

Describe the Dollo Parsimony Model

Answer 21

Character states reversible, ordered

No convergences possible

acquisition of a character state (from lower to higher value) can happen only once

change from state 0 to 1 can only happen once

change from state 1 to 0 can happen any number of times considering that it is evolutionary easier to lose a derived character state (than to evolve in parallel the same derived character state several
times ( convergence )