Animal Diversity II – Vertebrate Chordates Lab Report
**This week it is ok to NOT use complete sentences (unless it specifically asks for an explanation and
paragraph)! I would rather you answer all of these (even if it is with one word) to make sure you
understand. Also…do not forget that you cannot copy and paste answers as this is cheating!
Exercise 1 - Tetrapod Evolution
Great Transformations Interactive: Exploring Transitional Fossils
1. Which fossils DO NOT show tetrapod features? Coelacanth and Eusthenopteron
2. Which fossils DO NOT show any fish features? Perderpes and Telerpeton
3. Which fossil most closely resembles you? (hint: how many fingers do you have?) Perderpes
Tiktaalik resources:
4. Why did Shubin collect tropical fossils in Pennsylvania? Pennsylvania had rocky area that fit the
criteria of "right age", "right type" and as serendipity would have it the state of Pennsylvania's
Department of Transportation was carving out highways in bedrock so the right age, right type of
rock was being exposed.
5. What anatomical features did Tiktaalik possess that were both fish-like and tetrapod? Fins, gills,
scales and lungs
6. Why is a sturdy ribcage important for tetrapods? An animal on land uses lungs which need to be
protected, a sturdy ribcage prevents collapse.
7. Why do many of the transitional fossils between fish and tetrapods have flat heads? The head was
adapted to shallower waters in transition to land.
8. What did you find when examining the skull interactive? It is the similar features to what we have,
a braincase, a mandible, orbits, naris.
Exercise 2 - Ancient Fish
9. Approximately when did the coelacanth go “extinct?” They went "extinct" approximately 65 million
years ago until found again by Marjorie Courtenay-Latimer in December 1938, so It is actually not
extinct; it is still living today.
10. Why is the coelacanth a powerful link between aquatic and land vertebrates? It is one of the only
two lobe fish, they have all the bones we have in our hands.
11. Why are lobe-finned fish important to the history of tetrapods more so than ray-finned fish? Ray
finned fish are true fish, lobe fish are a closer evolutionary ancestry to the tetrapod with the one
bone, two bones, then digits.
Exercise 3 – Fish
HHMI Biointeractive on Stickleback evolution:
12. Provide a brief explanation of the different pelvic structures. Complete Pelvic structure: with a full
Pelvis and spine or any indication of a spine would be considered complete if found in a fossil as
long as we can see a spine.
Reduced: Partial pelvis of any amount, this would be any indication of a Pelvis, even a nub of a pelvis
would be Reduced as this would still indicate presence of Reduced Pelvis.
Absent: absolutely no indication of any pelvis whatsoever.
