Exam 2 PPTs - 3

Question 1

an evolutionary tree, also known as a phylogenetic tree or a phylogeny is:

• a diagram showing the history of … and …
• it depicts a group of organisms’ … relationships as they are understood according to Darwin’s theory of …

Answer 1

divergence;
evolutionary change;
genealogical;
descent with modification from common ancestors

Question 2

The root of the tree also represents the …

Answer 2

most recent common ancestor (MRCA) of all the organisms depicted

Question 3

All of the terminal “nodes” of the tree are … (…)

They are called …

Answer 3

operational taxonomic units; OTUs;

taxa (singular: taxon)

Question 4

All of the other, non-terminal nodes are … (…)

They are called …

Answer 4

hypothetical taxonomic units; HTUs; 
ancestral taxa (singular taxon)

Question 5

phylogenetic tree assumptions:

1. …
2. …

Answer 5

bifurcation;

the ancestral is never sampled

Question 6

….: a group that contains all the descendants of an ancestral taxa or node

Answer 6

monophyletic group

Question 7

…: a group that does not contain all the descendants of an ancestral taxa or node

Answer 7

paraphyletic group

Question 8

phylogenetic trees show … or …

Answer 8

character changes;

transitions

Question 9

… character: a relatively more recent or new character, derived from an ….

Answer 9

apomorphic character;

ancestral character

Question 10

… character: relatively more ancient, old or ancestral character

Answer 10

plesiomorphic

Question 11

apomorphic character:

• …: shared by two or more OTU. it defines a …
• ….: present in only one OTU. It does not define a group

Answer 11

synapomorphic;
monophyletic group;
autapomorphic

Question 12

monophyletic groups are formed by all … that share a …

Answer 12

OTUs;

synapomorphy

Question 13

sister taxa share a … with each other and are each other’s …

Answer 13

common ancestor;

closest living relatives

Question 14

phylogenetic trees have information about …

Answer 14

time

Question 15

the first stage of cladistic analysis is to distinguish … from …

Answer 15

homologies;

homoplasies

Question 16

homology is … due to …

Answer 16

similarity;

shared ancestry

Question 17

homoplasy is …

it is similarity due to … not …

Answer 17

similarity without ancestry;
convergence;
ancestry

Question 18

• the independent appearance in different lineages of similar derived characters is called …
• morphological similarities can arise independently, by …, when lineages experience similar patterns of … due to …

Answer 18

convergent evolution;
convergent evolution;
natural selection;
similar environmental challenges

Question 19

the loss of derived traits in a lineage, resulting in a return to the … condition, is called …

Answer 19

ancestral;

reversal

Question 20

the … principle: the simplest scientific explanation that fits the evidence
in terms of tree-building: the best hypothesis is the one that requires the …

Answer 20

parsimony;

fewest evolutionary changes

Question 21

…: it is possible to address questions about timing by analyzing molecular traits that change …

Answer 21

molecular clock;

at a steady rate

Question 22

…: it is possible to address questions about timing by analyzing molecular traits that change …

Answer 22

molecular clock;

at a steady rate

Question 23

Using phylogenies to answer questions:
how did the seychelles chameleon cross the Indian Ocean?
- chameleons can’t fly and are poor swimmers
two possibilities:
1. the chameleon simply … and rode the islands to their current position - The Seychelles were once part of the … of Gondwana
2. the chameleon reached the Seychelles by …, either from Madagascar or Africa

Answer 23

stayed put;
supercontinent;
floating on a raft of vegetation