Interpreting and Constructing Cladograms Lab | PDF | Phylogenetic ... - Free Printable

Let’s go step by step to solve the two questions based on the cladogram.

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Question 1: How many derived characteristics are represented on the diagram above?

Look at the labels along the branches of the cladogram. These are the “derived characteristics” — new traits that appear in a lineage and are shared by all organisms after that point.

From bottom to top, we see:

- Jaws
- Lungs
- Claws or nails
- Feathers
- Fur; mammary glands

That’s 5 labeled traits.

Note: Even though “Fur; mammary glands” is written as one label, it represents two traits — but in this context, since they’re grouped together on one branch mark, we count them as one derived characteristic event (i.e., one node where these traits evolved together). The question asks for how many *are represented on the diagram*, meaning how many trait labels are shown.

So we count each labeled tick mark:

1. Jaws
2. Lungs
3. Claws or nails
4. Feathers
5. Fur; mammary glands

→ Total = 5

✔ Confirmed: 5 derived characteristics are labeled.

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Question 2: Which animals have claws or nails?

Find the label “Claws or nails” on the cladogram. It appears on the branch *after* salamander and lizard split off, but before pigeon, mouse, and chimp.

That means any animal that comes *after* that point on the tree has claws or nails.

Looking at the order from left to right:

- Hagfish → no jaws even → definitely not
- Perch → has jaws, lungs? No — wait, perch is fish, doesn’t have lungs or claws → so no
- Salamander → has lungs, but does NOT have claws or nails (amphibians typically don’t have true claws/nails like reptiles/birds/mammals)
- Lizard → YES, reptiles have claws
- Pigeon → birds have claws (on feet) and nails (on wings sometimes, but definitely claws)
- Mouse → mammals have nails/claws
- Chimp → primates have nails

Wait — let’s check the branching carefully.

The “Claws or nails” trait is placed on the branch leading to lizard, pigeon, mouse, and chimp — meaning those four share that trait.

Salamander branches off BEFORE “claws or nails”, so salamander does NOT have them.

Perch and hagfish also branch off earlier.

So animals with claws or nails:

→ Lizard
→ Pigeon
→ Mouse
→ Chimp

That’s 4 animals.

But let’s double-check: In real biology, lizards have claws, pigeons have claws on their feet, mice have claws, chimps have fingernails (which are a type of nail). So yes, biologically accurate too.

✔ Final list: Lizard, Pigeon, Mouse, Chimp

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Final Answer:
1. 5
2. Lizard, Pigeon, Mouse, Chimp