1. A new Xenite species has been discovered. There is no fossil evidence to suggest the relative evolutionary age of this new species.

Question

Remake your character matrix and construct a new cladogram.
2. Explain how you created your new cladogram, and:
a. identify which derived characters were homologies or analogies
b. explain the evolutionary history of the organisms shown by your tree
c. explain how you used new evidence to revise your cladogram.

Answer 1

Character Matrix:

Organism | Char 1 | Char 2 | Char 3 | Char 4
----------------------------------------------
Xenite A | 0 | 1 | 0 | 1
Xenite B | 1 | 1 | 0 | 0
Xenite C | 1 | 0 | 1 | 1
Xenite D | 0 | 0 | 1 | 0

Cladogram:

+----Xenite C
|
+--|----Xenite B
| |
----| |
| | +------Xenite A
| +----|
| +------Xenite D

Explanation:

a. In creating the new cladogram, I identified the derived characters as follows:
- Char 1: Homology (shared by Xenite B and Xenite C)
- Char 2: Homology (shared by Xenite A and Xenite B)
- Char 3: Analogy (shared by Xenite C and Xenite D)
- Char 4: Analogy (shared by Xenite A and Xenite C)

b. The evolutionary history shown by the tree suggests that Xenite C and Xenite B share a more recent common ancestor with each other compared to Xenite A and Xenite D. Xenite A and Xenite B share a more recent common ancestor with each other, which is distinct from the common ancestor shared by Xenite C and Xenite D. This indicates that Xenite C and Xenite D are more distantly related compared to the other Xenite species.

c. Using the new evidence of the discovered Xenite species without fossil evidence, I revised the cladogram by comparing the shared derived characters among the different Xenite species to determine their evolutionary relationships. By analyzing the presence or absence of certain characteristics, I was able to rearrange the Xenite species in a way that reflects their likely evolutionary history.