Chapter 16 TB Vocab

Question 1

derived

Answer 1

• of a character, a state in some a group of species ancestral organisms that has been modified from a state in their ancestors

Question 2

ancestral

Answer 2

• a property of an ancestor
• often, a feature of a group of ancestral organisms that may or may not be modified in their descendants

Question 3

synapomorphy

Answer 3

• a derived character state that is shared by two or more taxa and is postulated to have evolved in their common ancestor

Question 4

monophyletic group

Answer 4

• taxon/branch of phylogenetic tree that includes all the species that descended from a common ancestor
• members all descend from single ancestor, but which does not include all the descendants of that ancestor
• members derived by evolution from ancestors in more than one ancestral taxon

Question 5

outgroups

Answer 5

taxon diverged from group of other taxa before they diverged from one another

Question 6

homoplasy

Answer 6

• independent evolution of similar traits
• possession by two or more speices of a similar or identical character state that has not been derived by both species from their common ancestor
• results from convergent evolution, parallel evolution, and evolutionary reversal

Question 7

evolutionary reversal

Answer 7

• return to earlier, ancestral character state
• evolution of a character from a derived state back toward a condition that resembles its state at an earlier timeline

Question 8

convergent evolution

Answer 8

• similar evolutionary changes
• evolution of similar features independently in different evolutionary lineages, usually from different antecedent features or by different developmental pathways

Question 9

incomplete lineage sorting (ILS)

Answer 9

• persistence of genetic polymorphism through a speciation event, so that fixation occurs only in the descendent species, or in their descendants after subsequent speciation

Question 10

likelihood

Answer 10

• estimation and inference based on porbability of a set of observations given a model for how those data were generated
• commonly used in DNA sequence phylogenetic trees

Question 11

Bayesian inference

Answer 11

• allows other info to be incorporated into estimate, combines prior info with data obtained later
• estimate phylogenies that are difficult using likelihood approach
• often used for phylogenetic trees based on DNA sequences, commonly used

Question 12

paraphyletic

Answer 12

• ## members all descend from a single ancestor, but which does not include all the descendants of that ancestor

Question 13

polyphyletic

Answer 13

• members derived by evolution from ancestors in more than one ancestral taxon
• aka composed of members that do not share a unique common ancestor