Study Guide: Exam 1 Ch. 16

Question 1

What are phylogenies used for?

Answer 1

All of life is related through a common ancestor. Phylogenies is the evolutionary history between these organisms.

Question 2

What is a clade?

Answer 2

A taxon that consists of all evolutionary descendants of a common ancestor.

Question 3

What is parsimony?

Answer 3

Parsimony principle: the preferred explanation of observed data is the simplest explanation. (minimizing # of evolutionary changes that are assumed)

Question 4

What is a monophyletic, a paraphyletic, and a polyphyletic group?

Answer 4

monophyletic - containing an ancestor and all desc. of that ancestor, and no other organisms (can be removed by a single “cut”).

paraphyletic - a group that does not include its common ancestor.

polyphyletic - a group that does not include all the desc. of a common ancestor.

Question 5

What is the root of a phylogenetic tree (that is, how can you identify it on a phylogenetic tree, and
what does it represent)?

Answer 5

An ancestor and its descendants population form a lineage, shown as a line drawn on a time axis.

Question 6

This question (number 36) has a figure to refer to, go back to the study guide to answer!

Answer 6

Refer to the study guide

Question 7

Drosophila yakuba and D.
santomea are the closest
relatives to each other.
Therefore, they are considered
_______ species.

Answer 7

Sister

Question 8

What is a synapomorphy?

Answer 8

Each character of an organism evolves from one condition to another. (ancestral trait –> derived trait).

synapomorphies = shared derived traits

Question 9

What is are homologous features?

Answer 9

• shared by two or more species
• inherited from a common ancestor

A.N.: Can be heritable traits, including DNA seq., protein structures, anatomical structures, and behavior patterns.

Question 10

What is the difference
between a synapomorphy, and a homoplasy?

Answer 10

Shared derived traits are called synapomorphies.

Homoplasy is when a character reverts from a derived state back to an ancestral state.

Question 11

What is convergent evolution? Give examples.

Answer 11

When superficially similar traits evolve independently in diff. lineages.

e.g.:
Most flowering plants produce both male and female gametes on the same individual (in pollen and ovules).

Question 12

This question (number 41) has a figure to refer to, go back to the study guide to answer!

Answer 12

Refer to the study guide

Question 13

According to the principle of parsimony, the best phylogenetic hypothesis is the one that requires
the fewest _____________.

Answer 13

homoplasies