SOLUTION: Cladogram worksheet practice key - Studypool - Free Printable

Actually, there is a major error in the provided answers for questions 1, 2, and 3 — because they refer to worms, spiders, ants, dragonflies, flies, and June Bugs, which are NOT part of the cladogram shown in the image.

The cladogram in the image includes:
- Lancelet (outgroup)
- Lamprey
- Tuna
- Salamander
- Turtle
- Leopard

And the shared derived traits are:
- Vertebral column
- Jaws
- Four walking legs
- Amniotic egg
- Hair

So the answers for questions 1, 2, and 3 are completely mismatched — they appear to be copied from a different worksheet that uses insects and arthropods, not vertebrates.

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✔ Let’s correct and answer the questions based on the actual cladogram shown:

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Question 1: According to your cladogram, which two species are more closely related: worms and spiders or worms and ants? How do you know?

✘ This question is invalid for this cladogram.
→ Worms, spiders, and ants are NOT in this cladogram.
→ The cladogram only includes vertebrates: lancelet, lamprey, tuna, salamander, turtle, leopard.

🟢 Correct Answer:
*This question cannot be answered using the given cladogram because none of these organisms (worms, spiders, ants) are included. The cladogram shows relationships among vertebrates only.*

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Question 2: According to your cladogram, what species are dragonflies most closely related to? How do you know?

✘ Again, dragonflies and flies are not in this cladogram.

🟢 Correct Answer:
*Dragonflies are not represented in this cladogram. Therefore, we cannot determine their closest relatives based on this diagram. This question belongs to a different cladogram involving insects.*

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Question 3: In a different colored writing utensil, add a June Bug to your cladogram based on its characteristics.

✘ June Bugs (beetles) are insects — they are invertebrates and do not have a vertebral column, jaws, legs like tetrapods, etc.

🟢 Correct Answer:
*June Bugs cannot be added to this cladogram because they are invertebrates and do not share the key traits (vertebral column, jaws, four legs, amniotic egg, hair) used to build this tree. They would branch off before the “Vertebral column” trait, likely near or with the outgroup (lancelet), but since they are not chordates, they wouldn’t even fit properly on this vertebrate-only cladogram.*

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✔ Now, let’s correctly answer the remaining questions (4–7) using the actual cladogram:

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Question 4: What trait separates lampreys from tuna on this cladogram?

✔ Answer: Jaws

🔹 Explanation:
- Lampreys are jawless vertebrates (they have a vertebral column but no jaws).
- Tuna have jaws.
- The trait “Jaws” appears at the node between lamprey and tuna — so it’s the first major trait that separates them.

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Question 5: What separates a salamander from a turtle?

✔ Answer: Amniotic egg

🔹 Explanation:
- Salamanders are amphibians — they lay eggs in water and do not have an amniotic egg.
- Turtles are reptiles — they have amniotic eggs (which allow reproduction on land).
- The trait “Amniotic egg” appears at the node after salamander and before turtle/leopard.

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Question 6: Which organism is most related to the leopard?

✔ Answer: Turtle

🔹 Explanation:
- On the cladogram, the leopard and turtle share the most recent common ancestor — they both have “Four walking legs,” “Amniotic egg,” and “Hair” (only leopard has hair).
- The turtle branches off just before the leopard, meaning they are each other’s closest relatives in this group.

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Question 7: Which organism’s DNA will differ the most from the leopard? Why?

✔ Answer: The lancelet

🔹 Explanation:
- The lancelet is the outgroup — it lacks all the derived traits (no vertebral column, no jaws, etc.).
- It branched off earliest in evolutionary history relative to the others.
- Therefore, it shares the fewest traits with the leopard and is the most distantly related → its DNA will differ the most.

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## 📌 Summary of Corrections:

| Question | Provided Answer | Correct Answer |
|----------|------------------|----------------|
| 1 | Worms & spiders | Invalid — not in cladogram |
| 2 | Dragonflies & flies | Invalid — not in cladogram |
| 3 | Add June Bug | Cannot be added — not a vertebrate |
| 4 | JAWS | ✔ Correct |
| 5 | AMNIOTIC EGG | ✔ Correct |
| 6 | TURTLE | ✔ Correct |
| 7 | LANCELET | ✔ Correct |

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✔ Final Note: The first three questions were likely copied from a different assignment. Always make sure the questions match the diagram! For this specific cladogram, focus only on the six vertebrates shown.

Let me know if you’d like help drawing where June Bugs *would* go on a broader animal cladogram!