Cladistic Terms

Question 1

anagenesis

Answer 1

Change occurring within a lineage

Question 2

ancestral (primitive) state
plesiomorphic

Answer 2

the character state exhibited by the ancestor form which current members of a clade have evolved

Question 3

apomorphy

Answer 3

any derived or specilized character

Question 4

autapomorphy

Answer 4

a derived character possessed by only one descendant of an ancestor, and thus no use in discerning relationship among other descendants

Question 5

bayesian inference

Answer 5

a statistical technique used to infer the probability that a particular phylogenetic hypothesis is correct

Question 6

bootstrapping

Answer 6

technique to evaluate reliability of branch of phylogenetic tree by resampling some characters form original data set

Question 7

clade

Answer 7

a group of organisms that includes the most recent common ancestor of all its members and all descendants of that ancestor; every valid clade is “monophyletic group”

Question 8

cladogenesis

Answer 8

the splitting of a single lineage into two or more distinct lineages

Question 9

cladogram

Answer 9

the pictorial representation of branching sequence that are characterized by particular changes in key morphological or molecular characteristics

Question 10

derived state
apomorphic state

Answer 10

an altered state modified form original or ancestral condition

Question 11

homologous characters
homology

Answer 11

characters that have the same evolutionary origin form a common ancestor, often coded for by the same genes

Question 12

homoplasy

Answer 12

the independent acquisition of similar characteristics (character states) form different ancestors though convergent or parallelism. create illusion of homology

Question 13

jackknifing

Answer 13

technique for evaluating the reliability of a branch of phylogenetic tree by deleting some percentage of info at random and then rerunning the analysis

Question 14

monophyletic taxon

Answer 14

a gorup of species that evolved forma. single ancestor and includes all descendants of that ancestor

Question 15

node

Answer 15

a branching point on cladogram

Question 16

outgroup

Answer 16

a group of taxa outside the group being studied

Question 17

paraphyletic group

Answer 17

a group of species sharing immediate ancestors but not including all descendants of ancestor

Question 18

parsimony

Answer 18

least complex is usally anser

Question 19

pleisiomorphy

Answer 19

any ancestral or primative character

Question 20

polarity

Answer 20

the direction of evolutionary change

Question 21

polyphyletic grouping

Answer 21

incorrect grouping containing species that descended form two or more different ancestors. independently evolved similar traits by different ancestors

Question 22

saturation

Answer 22

situation in which the gese sequences being compared have experinced so many base-pair substitutions that the phylogenetic signal is largely lost

Question 23

sister gorups

Answer 23

tow groups of animals descended from the same immediate ancestor

Question 24

synapomorphy

Answer 24

derived character that is shared by the most recent common ancestor and by two or more descendants of that ancestor. define clades. homologous characters taht defien clades

Question 25

taxon

Answer 25

any named group of organisms