Biology of the Vertebrates Study Questions F2014

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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.

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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 are 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.

4. What were Tiktaalik's fish-like traits? In what ways was it unique (i.e., different from both its sarcopterygian ancestors and the tetrapod lineages to which it is most closely related)? When and where did it occur?

Lecture 11 (2 Oct 2014)

1. What is Ichthyostega? What were its fish-like traits? Its tetrapod-like traits? In what ways was it unique? When and where did it occur?

2. Explain the differences between Ichthyostega and Tiktaalik and how they relate to their relative positions on the vertebrate phylogenetic tree.

3. What are zygopophyses? What is their function? When did they first evolve?

4. What are the adaptations that allow caecilians to successfully live and capture prey underground? Describe caecilian reproduction. Describe a unique, recently-described caecilian parental behavior. How does this benefit their offspring?

5. What morphological characteristics does Eocaecilia share with extant caecilians. What morphological characteristics differ between the two?

6. Describe salamander reproduction (as seen in most lineages). Why is this considered indirect internal fertilization?

7. Explain the relationship between ectothermy and biomass in relation to caudates. Why are caudates so important to ecosystems?

8. Compare the feeding strategies of aquatic and terrestrial salamanders. Why and how are each adapted to capture prey in their respective environments?

9. Are all frogs toads? All toads frogs? Explain your answer.

Lecture 12 (7 Oct 2014)

1. Identify synapomorphies for caecilians (Apoda) and frogs (Anura), as well synapomorphies of all amphibians.

2. What are the two types of skin glands founds in all living amphibians? Please list the functions of each gland type.

3. Describe the amniotic egg and the function of each of the three membranes.

Lecture 13 (9 Oct 2014)

1. In what ways were the ancestors of amniotes still dependent on water? Which adaptations have amniotes evolved to lessen their dependence on water and become largely terrestrial?

2. Which are the synapomorphies of each of the following lineages: amniotes, sauropsids, lepidosaurs? Draw the amniote phylogeny. Draw the tetrapod phylogeny.

3. What is the evolutionary/adaptive significance of tail autotomy? Which structures in the tail do not regenerate when it grows back? What are these structures replaced with?

4. What is temperature-dependent sex determination? In what lineages discussed in today's lecture is it found in?

5. Compare and contrast the diversity, morphology, reproductive behavior, ecology, and geographical distribution of sphenodons (tuataras) to that of squamates (lizards, snakes).

6. What is the functional significance of the diapsid skull evolution?

7. Why ectotherms are better than endotherms at using patchy (spatial and temporal) resources?

8. Explain why lizards are not a monophyletic group.

9. What are the challenges of living in a desert environment? How do squamates cope with each of these challenges? In what ways are lizards able to thermoregulate? Explain how some ectotherms can be homeotherms.

10. What is thought to be the most important feature for the evolutionary success of snakes?

Lecture 14 (14 Oct 2014)

1. What are the parts of a turtle shell? What is the shell composed of? In what ways is having a shell beneficial? How is it disadvantageous (not beneficial)?

2. When did turtles evolve? Briefly describe the process of morphological transition between an early amniot body plan and the derived turtle morphology.

3. Name the three potential phylogenetic placements of turtles and each of the major lines of evidence supporting them.

4. Which is the importance of the trochlear process in turtle evolution?

5. Provide at least 6 turtle synapomorphies. Which of these synapomorphies is seen only in modern lineages of turtles? In what way do modern turtles differ from the 220 million year old fossil Proganochelys? What are the similarities between this fossil and modern turtles?

6. What are the two major lineages of turtles? What is the key morphological/anatomical difference between members of these two lineages?

7. How does morphology differ between turtles that are primarily terrestrial and those that spend most of their time in the water?

Lecture 15 (16 Oct 2014)

1. Describe five synapomorphies of the Archosauria. In what ways have these synapomorphies allowed archosaurs to be highly efficient and successful predators?

2. What type of predator is a crocodilian? How have these synapomorphies allowed crocodilians to exploit this particular type of predatory strategy?

3. What is a synapomorphy of the Crurotarsi? Where are crocodilians located relative to dinosaurs on the phylogeny? Which EXTANT group is most closely related to crocodilians? Why aren't these two extant lineages considered sister groups?

4. What are the three major lineages of crocodilians. Discuss a few major morphological and ecological characteristics of each these families.

5. What do crocodilians and turtles have in common regarding their reproductive biology? How do they differ?

Lecture 16 (21 Oct 2014)

1. If we know both birds and crocodilians build and defend nests, care for hatchlings, and have complex social behavior, what can we infer about the extinct lineages of Archosauria?

2. Explain the differences among anapsid, synapsid, and diapsid skull conditions. What bones and morphological characters are important in telling these conditions apart?

3. What kind of skull does a turtle have? How did their skull morphology influence where scientists have placed turtles on the vertebrate phylogeny historically?

4. What is the major trend in Ornithodirans we discussed in class? Whas this trend allowed Ornithodirans to do?

Lecture 17 (23 Oct 2014)

1. Describe some of the morphological characteristics related to flight, and collectively, their ecological implications. What is the first lineage of vertebrates that we see flight as a mode of locomotion? How were they flying (i.e., flapping or gliding)? What are the two main lineages of this group and how do they differ?

2. Which morphological synapomorphy of pterosaurs resembles their name?

3. In what ways were pterosaurs morphologically and ecologically diverse?

4. Name the possible functional hypotheses of pterosaur head and snout crests.

5. List the synapomorphies for the following clades: Ornithodira, Pterosauria, and Dinosauria.

6. Name a reason that allowed dinosaurs to be giant.

7. What extant lineage needs to be included in order for Dinosauria to be considered a monophyletic grouping? What is the ancestral condition of Dinosauria, bipedalism or quadrupedalism?

8. What are the two major groups in Dinosauria? How does the pelvic arrangement differ between these groups? Which of these groups is the one leading to birds, and why are the common names of these groups misleading?

Lecture 18 (28 Oct 2014)

1. What is the functional significance of the differences in the pelvic arrangement between the two major groups in Dinosauria?

2. List six Ornithiscian synapomorphies. Give at least four examples of ornithiscian dinosaurs.

3. Comment on the diets of ornithiscians and saurischians. In what ways do you think diet has influenced their anatomy (i.e., think how the rib cage and pelvis orientation differs between these two lineages)?

5. What do Stegosaurus and Ankylosaurus have in common (besides being Thyreophora)?

6. Which are the theories for the diversity of head structures in Ornithiscians?

7. What are the major saurischian synapomorphies? What are the two main groups within Saurischia? Which is the lineage leading to birds?

8. What was the Sauropod diet and which morphological adaptations are associated with it?

Lecture 19 (4 Nov 2014)

1. Are hollow bones restricted to flying animals? Justify.

2. List the Theropoda synapomorphies. What are the three main lineages within Theropoda? Name a representative and distinctive characteristic of each group.

3. How does the jaw joint in the lower jaw benefit therapods?

4. What fossil evidence provides support that saurischians had parental care in the form of nest building and attendance?

5. What is a morphological distinctive feature of maniraptors? In what ways has this synapomorphy contributed to flight in modern birds?

Lecture 20 (6 Nov 2014)

1. Feathers evolved in Theropods, why wasn't there a need to evolve feathers in Sauropods?

2. What is Archaeopteryx? When was it discovered and what geological period does it date back to? How large was it?

3. Why was the discovery of Archaeopteryx so significant? In what ways is Archaeopteryx similar to both dinosaurs and modern birds? In what ways does it differ from Aves (birds)?

4. What came first, feathers, flight, or dinosaurs? Describe the evolutionary relationship between feathers and flight in birds.

5. What is the significance of the large find of fossils in China ~ 15 years ago?

6. So far, what evidence for birds being dinosaurs do you find most convincing and why?

Lecture 21 (11 Nov 2014)

1. What are some proposed reasons feathers evolved?

2. What are the three proposed theories for the evolution of flight (for birds)? Which of these do you think is best supported by the evidence?

Lecture 22 (13 Nov 2014)

1. What are the four major mating systems found in birds? Which are the most common? Which are the least? Why are some more common than others?

2. What is the most important factor for dictating avian mating systems? Describe the differences between altricial vs. precocial offspring. How does precocial vs. altricial condition of offspring relate to the type of mating system exhibited by the parents?

3. Are most birds truly monogamous? Explain the different forms of "monogamy" and how each parent benefits from different forms of monogamy. When would each type be selected for?

4. What influences the form of polygamous mating systems? What factors underlie the differences between male & female interests in reproduction?

Lecture 23 (18 Nov 2014)

1. Why do females get to be so choosy about males? How do males try to convince females that they are the best possible male?

2. Why are males more likely to desert a reproductive alliance than females? What makes parental care such an important investment; i.e., what are the potential costs?

3. How does hovering flight (in hummingbirds) differ from flapping flight in other birds?

4. Name one skeletal and one muscular modification that provides evidence for birds' commitment to flight.

5. Why do birds have higher metabolic rates (when compared to other major vertebrate groups)?

6. Which are two adaptations in the jaws of birds that are related to their flying lifestyle?

Lecture 24 (20 Nov 2014)

1. Explain the differences between the hearts of Turtles, Lizards, Crocodiles, Birds and Mammals.

2. What’s the difference between a synapomorphy and a trend? Describe several important trends in the Synapsida.

3. Name the main four groups of synapsids. Are they paraphyletic or monophyletic? Which is the only surviving group of synapsids?

4. Describe major features mammals have that are evident from the fossil record.

5. Which changes in the jaws lead to the transition from the reptilian to mammalian jaw joint? How does this relate to hearing?

Lecture 25 (2 Dec 14)

1. What are the three major groups of extant mammals? What does the mammalian phylogeny look like?

2. How are monotremes typically distinguished from the other two? Is this a good way of characterizing a group?

3. What are the two major groups within Monotremata? Give examples of species and their major characteristics.

4. Describe the major characteristics of marsupials. Where do they occur? Where are they most diverse? Give examples of some species and their characteristics.

5. What is the difference between altricial and precocial offspring? Which are the advantages and disadvantages of each parenting strategy?

Lecture 26 (4 Dec 14)

1. Which major evolutionary feature characterizes Eutheria? How diverse is this group?

2. Eutheria is characterized by prolonged retention of offspring. Describe the main ways in which this is accomplished.

3. Describe some advantages and disadvantages of eutherian reproduction, particularly with regard to prolonged retention of young.

4. Name the convergent clades that have evolved specialized insectivory to catch ants and termites and describe their morphological adaptations.

5. Why are bats so special among mammals?

6. Describe the morphological traits associated to carnivory in mammals and provide particular examples.

7. What is the difference between digitigrade and unguligrade organisms? What is the benefit of being a unguligrade?

8. Why aren't humans considered monkeys?