Lecture 10-12 - Phylogenetics

Question 1

What is a synapomorphy?

Answer 1

A homologous trait shared by all clade members which reflects common ancestry.

Question 2

What is a polyphyletic group?

Answer 2

All group members minus the most recent common ancestor.

Question 3

What is a paraphyletic group?

Answer 3

An ancestor but only some of its descendants.

Question 4

What is parsimony?

Answer 4

If all other things are equal, the best phylogenetic tree hypothesis will be the that requires the fewest evolutionary changes

Question 5

What is the difference between orthologous and paralogous genes?

Answer 5

Paralogous genes are duplicated within a species that then diverge while orthologous genes are similar genes within 2 species that have already diverged from a common ancestor.

Question 6

Why are orthologous genes beneficial?

Answer 6

They diverge after 2 gene pools are isolated from each other so the extra copy of the gene allows for modifications without the loss of the original.

Question 7

What is the molecular clock?

Answer 7

Estimating the time of evolutionary change using genes that appear to evolve at a constant rate or neutral genes.