Phylogenetic Trees

Question 1

Phylogenetic Tree

Answer 1

visual representation of the relationship between different organisms, showing the path through evolutionary time from a common ancestor to different descendents

Question 2

Branches

Answer 2

represent a lineage

Question 3

Nodes

Answer 3

where lineages diverge, represent a speciation event from a common ancestor

Question 4

Root Node

Answer 4

represents the most recent common ancestor of all taxa represented in the tree

Question 5

Monophyletic Group / Clade

Answer 5

a group of taxa that includes a common ancestor an ALL of its descendents

Question 6

Non-Monophyletic Group

Answer 6

a group of taxa that does not include ALL of the descendants of a common ancestor

Question 7

Synapomorphy

Answer 7

shared, derived trait of the members of a monophyletic group that evolved along an ancestral branch

Question 8

Data Used to Construct Trees

Answer 8

1. Morphological Data (structural features, organs, skeletal arrangements)
2. Genetic Data (mitochondrial DNA sequences, ribosomal RNA genes, genes of interest)
3. Homology (similarity due to a common ancestor)
4. Parsimony (most likely-preferred-topology is the one requiring the fewest changes)

Question 9

Parsimony

Answer 9

trees are constructed on the principle that the most likely pattern is the one requiring the fewest changes

Question 10

Clade

Answer 10

group of taxa that includes a common ancestor and all of its descendants

Question 11

Important to remember

Answer 11

monophyletic group = clade

Question 12

most important tree rules

Answer 12

• none of the organisms are the “most evolved”
• ALL ORGANISMS HAVE BEEN EVOLVING FOR THE SAME AMOUNT OF TIME