QUESTIONS

Use the phylogenetic trees at the end of this pdf to answer the following questions. Clicking on the lineages

on the phylogenetic trees will take you to the Wikipedia entry for that group.

1. Which node in the 3-domain supertree (the first tree) represents the common ancestor of eukaryotes and

Archaea? Which node in the 3-domain tree represents the common ancestor of all Eukaryotes? What are

some characteristics that would have been present in the common ancestor of all eukaryotes? Think about

characteristics that are shared between your cells and the cells of all these other groups (2 pts).

2. List all of the acquisitions of photosynthetic found in eukaryotes below (give either the numbered node

where it evolved or the name of the lineage in which it occurred) (2 pts).

3. Unikonta don't have any true chloroplasts or photosynthetic lineages, but describe the similarities and

differences between Lichens and chloroplast-containing eukaryote lineages. (1 pt)

4. Identify the node in the Archaeplastida phylogeny where the diploid sporophyte generation became the

dominant stage in the life cycle (1 pt).

5. Identify the node in the Archaeplastida phylogeny where land plants evolved. (1 pt)

6. Which node represents the most recent common ancestor of Seed Plants? (1 pt)

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7. Which node represents the most recent common ancestor of Gymnosperms. Conifers are, by far, the

most species-rich lineage of modern Gymnosperms; do you think the most recent common ancestor of seed

plants would have had needles like a pine tree or broad leaves more like most angiosperms? (2 pts)

8. Which node is the most recent common ancestor of Angiosperms (flowering plants)? These are now the

most species-rich lineage of embryophytes by far with approximately 350,000 species. Most of these species

(including all monocots) are herbaceous, meaning they don't form a woody trunk with internal vascular rings

or bark Amborella trichopoda is a shrub from New Caledonia that represents the basal branch of

Angiosperms (i.e. all other flowering plants are more closely related to each other than they are to

Amborella). Do you think the ancestor of angiosperms was woody or herbaceous? What about the ancestor

of all seed plants? (hint: Amborella, Ginkgo, all conifers, Gnetophytes, and Cycads have woody "trunks")? (2

pts)

9. Sponges have specialized individual cells but lack true tissue (masses of coordinated cells, like muscle,

nerve, etc.). At what node in the animal phylogeny did true tissues evolve? (1 pt)

10. At what node in the animal phylogeny did bilateral symmetry evolve (hint: sponges and cnidarians aren't

bilaterally symmetric, but every other organism on the animal tree technically is)? Bilaterally symmetric

animals have a left and right side, as well as a dorsal and ventral side. Based on the organisms on this tree,

what do you think this bilateral common ancestor may have looked like? (2 pts)

11. You have two forelimbs (arms) and two hindlimbs (legs). At which node in the phylogeny did these paired

appendages evolve? Are there any instances of convergent evolution of paired appendages? Are there any

instances of losses of paired appendages? Give the examples, if they exist (2 pts).

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12. Identify the node in the phylogeny where your ancestor first colonized land (hint: this is also the common

ancestor of organisms with fingers and toes). Give an example of a descendant from that ancestor that has

gone back to living a fully aquatic lifestyle. List any other examples of animal lineages that appear to have

colonized land independently of your ancestor (2 pts).

13. Are fish (i.e. jawless fish, cartilaginous fish, ray-finned fish, and lungfish) monophyletic? i.e. Do they trace

back to a single common ancestor, and are all descendants of that most recent ancestor considered fish? (1

pt).

14. Chambered Nautilus is the first-branching lineage of Cephalopods. Do you think Octopuses/Octopi

evolved from a shelled ancestor? Explain why or why not (1 pt).

15. List all of your ancestors (list of node numbers) from both the animal tree and the 3-domain tree. (2 pts).

16. Go outside and take photographs of 4 different organisms, each representing a different terminal group

on the tree. Identify where they belong on the tree and submit photographs. A maximum of 2 animals or 2

plants are allowed, and at least one of your selections must be something other than an animal or plant. (2

pts)