Question 1. What two things do nodes represent on phylogenies?
Nodes represent the most recent common ancestor of two or more descendant
lineages and represent a speciation event.
Question 2. Compare the branching patterns of phylogenies 1-3 above. Which
statement below correctly describes the patterns among trees 1-3?
Tree 1 = Tree 2
Question 3. Which node represents the MRCA for taxa F and G?
3
Question 4. Which taxon or taxa is/are the sister group to E + F?
D, G, H
Question 5. If you wanted to determine how long-ago birds diverged from therapod
dinosaurs, which type of phylogenetic tree would you use and why?
I would use a chronogram because it shows the pattern of lineage splitting with a
specific amount of time, and the others don't have a measure of time
Question 6. Genetic data in the form of nucleotide sequences is routinely used to build
phylogenies. What do you think the character states are for this type of data? (hint:
there are four states).
adenine, guanine, thymine, cytosine
Question 7. Mammals are the only animals that have hair. Would you consider the
presence of hair in mammals to be an ancestral or derived trait among all animals?
Why?
Derived because it is unique to mammals. If it were ancestral, then other animals
besides mammals would have hair.
Question 8. Many groups of animals have defensive spines. Examples include
porcupines, sea urchins, and hedgehogs. What information do you need in order to
determine whether or not spines are the result of homology or homoplasy?
We need to know the phylogeny so we can see if they inherited defensive spines from a
MRAC or if it is from convergent evolution.
Question 9. We are going add one more taxon to table 1.2 above. Taxon X lacks growth
from the tip, does not have cells for support, has small leaves, and lacks seeds. Use
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