Biology of the Vertebrates Study Questions F2014
Note: These study questions are not comprehensive. They are meant to supplement your lecture notes as you review them, and alert you to the ways in which you should be thinking about the material, and formulate questions to test yourself. Exams will NOT be limited to the material highlighted in these questions, or their formats, so your lecture notes and handouts should be your primary reference.
Lecture 1 (26 August 2014)
1. Dr. Jockusch mentioned that holistic, integrative studies have largely gone by the wayside, in lieu of increased research specialization on levels of organization rather than organisms. What is the purpose of studying "the biology of the vertebrates?"
2. What is the most basic function of an individual vertebrate? Name two of the other functions mentioned in class, and explain how they influence this most basic function. Give a specific example of each.
3. How do iguanas breathe differently than humans, and how does this affect an iguana's ability to capture food?
4. Explain what a "trade-off" is, using the Hydromantes salamander's ballistic tongue as an example.
Lecture 2 (28 August 2014)
1. Are sharks more closely related to birds or hagfish?
2. When Dr. Jockusch says, "We [humans] are all bony fish," what does she mean?
3. Define "synapomorphy," and name one for echinoderms and chordates.
4. What is a "sister group?"
5. On a phylogenetic tree, which conveys more information, the order of the taxa listed on the tips, or the arrangement of the branches? Why?
6. Is the ancestral state for the Testudines, aquatic or terrestrial?
7. Which of the 12 extant vertebrate lineages don't occur in a marine environment? And of those, which have never lived in a marine environment?
Lecture 3 (2 Sept 2014)
1. What does it mean that urochordates have an open circulatory system? How is that different than a closed circulatory system and what is the function of the circulatory system?
2. Hagfish are often called "living fossils." Why?
3. What is the difference between an atriopore and an anus?
4. What is a novel characteristic of the lancet's gut, and what is its significance?
5. How do Urochordates and cephalochordates filter water?
6. Draw a simple phylogenetic tree with vertebrates, urochordates, and cephalochordates, in addition to the deuterostome phyla.
7. Which traits of urochordates and cephalochordates are synapomorphies for vertebrates?
Lecture 4 (4 Sept 2014)
1. What are two synapomorphies that unite Myxinoidea and Petromyzontoidea? What are two synapomorphies for vertebrates?
2. The oldest freshwater lamprey fossil is considerably more recent than the oldest marine lamprey fossil. What can we infer from this?
3. Name a characteristic of hagfish that is an example of a "lost" trait. Why might organisms "lose" traits their ancestors once had?
4. Both lampreys and hagfish have caudal fins, with one major difference. What is this difference, and why is it important?
5. Compare the hypothetical "ancestors" of both chordates and vertebrates. What are the major adaptations that occur between these two hypothetical species?
6. What are the major differences in reproductive strategy between lampreys and hagfish? What are the advantages and disadvantages of each?
7. Explain the difference between the Myxinoidea and Petromyzontoidea's keratinized "teeth" and how they use them to acquire food.
Lecture 5 (9 Sept 2014)
1. What are the morphological and molecular hypotheses for the placement of Petromyzontoidea on the phylogenetic tree of vertebrates? Describe how these different hypotheses change our understanding of the evolutionary history of at least one trait.
2. What are agnathans and why aren't agnathans monophyletic? And why does this mean that the group can't be placed on a phylogenetic tree?
3. From what we discussed in class, give two examples of what we can learn by studying the fossil record.
4. What are conodonts and where are they currently placed on the vertebrate tree? Give two traits that justify this placement, and explain why the current placement is uncertain.
5. What characteristics of Metaspriggina identify it as a vertebrate, and not another kind of chordate?
Lecture 6 (11 Sept 2014)
1. How, why, when, and where did jaws evolve? (i.e. What was the original function of jaws? When did they evolve, and where? What anatomical feature did they evolve from?
2. When did placoderms "rule" the oceans? When we call them ecologically diverse, what does that mean? When did they go extinct?
3. What are the three mineralized tissue layers that compose the external skeleton (dermal armor) of jawless armored fishes? What are the hypothesized functions of the external skeleton? Why does the evolution of dermal armor matter to humans?
4. The Chondrichthyes are known as "cartilaginous fishes;" however, we've discussed older lineages of fish with cartilage. What differentiates the cartilage found in the Chondrichthyes?
5. What are the synapomorphies for the Chondrichthyes, and what are the two major groups within Chondrichthyes? Give an example of each.
6. Name two traits that distinguish ratfish from sharks.
7. In the waning moments of class, Dr. Jockusch talked about reproduction in sharks. Explain how sharks reproduce. How can a female shark control parentage?
Lecture 7 (16 Sept 2014)
1. What is viviparity? In what vertebrate lineages do viviparous organisms occur?
2. Define "sister group." Name the sister groups of the following taxa: sharks, elasmobranchs, Chondrichthyes, and gnathostomes.
3. Describe two differences between rays and other elasmobranchs.
4. In what similar way do the Holocephali and rays move through the water? Is this a shared derived trait or did it evolve independently? How does this method of locomotion influence the morphology of their tails?
5. What is a subterminal mouth? Is this trait a synapomorphy for the Chondrichthyes?
Lecture 8 (18 Sept 2014)
1. What are the benefits of mineralized cartilage when compared to bone? What effect does this have on a Chrondricthyes maximum body size and why?
2. What are three synapomorphies for the Osteichthyes? What are the two extant groups of osteithchyans?
3. What are the five groups within the Actinopterygii? How many species are found within each, and what is the distribution of each of these groups?
4. What's the difference between how chondrichthyans and osteichthyans support their fins?
5. Explain how lungs evolved, and why. How does this give us insight into where the first bony fishes evolved? What extant lineages of fish have lungs?
6. Draw a diagram of how a swim bladder works, including the ovale and gas gland. Why is regulating the pH of the blood crucial to the function of swim bladders? What is a secondary function of the swim bladder found in some fish?
7. Describe and name three advantages of jaw protrusion in teleosts. Which traits involved in jaw protrusion are synapomorphies of teleosts?
8. What is the function of pharyngeal jaws? From what morphological character did they evolve?
9 Dr. Jockusch described herbivorous fish as "keystone" species on coral reefs. What does this mean? What effect do herbivorous fish have in these habitats?
Lecture 9 (23 Sept 2014)
1. What is the functions of the coelacanth's (Actinistia) lungs and rostral organ? What are other characteristics independently evolved in other taxa we'd studied that provide similar functions?
2. What are the key morphological/anatomical characteristics that differentiate coelacanths from Actinopterygians and other Sarcopterygians?
3. We saw a video that shows a lungfish using its pelvic appendages to push itself forward. Why may this be an important trait from a phylogenetic perspective?
4. Compare the distributions of coelacanths and lungfish. What traits may account for the differences we see in where they live?
Lecture 10 (30 Sept 2014)
1. Describe how a lungfish can facultatively switch between breathing aquatically and aerially.
2. What is aestivation? When did it evolve and in what lineage? How does it work and why do the organisms in question do it?
3. Name three morphological traits that help the Tiktaalik live semi-terrestrially; explain how these traits work and how they are different from their aquatic ancestors.