Biology of the Vertebrates Study Questions F2012

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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 (27 August 2013)

1. What are the reasons for studying a particular group of organisms such as vertebrates?

2. When an organism is considered an "ecosystem engineer"?

3. Organize the vertebrate groups from the most to the least diverse (# of spp.).

4. What might account for the differences in numbers of species among vertebrate groups? Roughly what fraction of animals do vertebrates comprise?

5. What is “cladistics”? Define “monophyly,” and describe how this differs from “paraphyly.”

6. What is a "monophyletic group"? Draw the vertebrate phylogeny and label all major monophyletic groups discussed in lecture.

7. Define “synapomorphy” and “plesiomorphy.” Explain how a synapomorphy at one level can be plesiomorphic at another (or vice-versa).

8. Provide an example of a bad character to use when reconstructing the evolutionary history of an organism.

9. What is evolutionary convergence and how could it bias a phylogenetic reconstruction?

10. What is a "paraphyletic group"? Give an example for vertebrates.

11. What is the blastopore? Explain the importance of understanding the embryonic development of the blastopore.

12. What is the evolutionary significance of Pikaia?

Lecture 2 (29 August 2013)

1. Describe three major innovations in the vertebrate history reviewed in today's lecture.

2. What are ‘homologous’ structures? Provide an example.

3. What is bone comprised of, and how does it differ from cartilage? Provide an example of an animal, or group of animals that lack true bone.

4. Describe the two major components of the vertebrate skeletal system. What features does each part contain?

5. Describe the three basic elements of the skull. What were each of these regions initially derived from?

6. How does the tetrapod vertebral column differ from the ancestral condition, both in its morphology and capacity for movement?

7. Briefly explain the major transitions in the appendicular skeleton from sharks, to bony fishes, to lobe-finned fishes, and to terrestrial tetrapods.

8. In ancestral vertebrates, such as bony fishes, axial muscles are divided into _________. What are the major regions of axial musculature called? With which features are the hypobranchial muscles associated?

9. Compare the skulls of humans and fish, how are they different and what are the evolutionary reasons for these differences?

10. What is paedomorphosis? Please provide an example of a paedomorphic trait.

11. What are zygapophyses and what is their evolutionary significance?

12. Why are ribs reduced in amphibians when compared to other vertebrates?

Lecture 3 (3 September 2013)

1. What does the term plate tectonics refer to? Why do plate tectonics matter for vertebrate evolution? Define continental drift'’ and ‘'subduction'’, and provide examples for each.

2. The first fossil evidence of vertebrates is from which geologic period? How were most of the continental land masses situated during this time, and what were the environmental conditions like?

3. Describe some key features of Myllokunmingia. When did it evolve? Why is this fossil significant when discussing vertebrate evolution?

4. What are conodonts? When did they evolve? Why did it take so long to determine what they actually were (i.e., what organism they belonged to)? Where would you place conodont fossils on the vertebrate phylogeny?

5. Describe some key features of the ostracoderms. When did they evolve, and roughly when did they go extinct? Which group experienced a major radiation during the Silurian? Some ostracoderms had hypocercal tails, and others heterocercal tails – what does this mean?

6. Which group of ostracoderms is a potential ancestor lampreys? Why do scientists think that?

7. Describe some similarities and differences in morphology and ecology between the two living (extant) jawless vertebrates.

8. Describe how the feeding apparati of hagfishes and lampreys are different when compared to gnathostomes.

9. Both hagfish and lampreys are similar in overall body size and shape (e.g., elongate, and without paired appendages). What are some key morphological/anatomical features that can be used to differentiate between these two groups?

10. Describe the life history and reproductive behavior of the lamprey (Petromyzontoidea). In which ways does it differ from that of the hagfish (Myxinoidea)?

11. List the six main gnathostome characteristics. Roughly when did jaws evolve? Briefly explain Mallatt’s hypothesis regarding the evolution of jaws from jawless, filter-feeding ancestors. List the four main gnathostome groups present between the Silurian and Devonian.

12. Describe some of the major characteristics of placoderms, and how they differ from the ostracoderms. Why are the "teeth" of Dunkleosteus not homologous (i.e., evolutionarily related structures) to the teeth of other vertebrate lineages, like sharks, bony fishes, and mammals?

Lecture 4 (5 September 2013)

1. Be able to answer the who, what, where, when, why, and how questions for vertebrate traits discussed in lecture. For example, the origin of jaws is seen in the ancestor to what lineages? In what environment did jaws evolve? In what geological time period did jaws evolve? What anatomical feature are jaws modified from? What is the ancestral function of jaws? What is the primary function of jaws in most extant gnathostome (jawed vertebrate) lineages?

2. Name and describe the two major extant (living/modern) clades of Chondrichthyes. How do these differ from one-another (particularly in terms of skull morphology)?

3. How do modern sharks differ from their ancestral counterparts (give at least three major characteristics)?

4. Which is the period called the age of fishes and why? When in geologic time did cartilaginous fishes arise?

5. Describe the two major shark radiations. Roughly when did each occur, and how did sharks from the second wave differ from those from the first?

6. List and briefly describe some important characteristics of modern sharks, in terms of their: (a) morphology (general anatomy, shape, size range) (b) physiology (e.g., osmopregulation) (c) reproductive biology (e.g., fertilization; oviparity/viviparity).

7. What proportion of elasmobranchs are oviparous? Describe two types of viviparous eggs.

8. Elasmobranchs have a large diversity of tooth shapes. Describe two different shapes seen in sharks and rays. What are the functions of each of these different tooth shapes?

9. Describe the morphological differences and evolutionary transitions between Paleozoic and Modern sharks.

10. What is peculiar about shark teeth and why they evolved such peculiarity?

11. What do manta rays, basking sharks, whale sharks and whales have in common? Which evolutionary pattern could you infer?

12. Describe convergent evolution and give an example among elasmobranchs.

Lecture 5 (10 September 2013)

1. List the major groups of bony fishes. When do they first appear in the fossil record?

2. Give the three major physical characteristics shared by all Teleostomes. Give at least two physical characteristics shared by all acanthodians.

3. Name two important representatives of lobe-finned fishes, and describe the general habitats they inhabit. Geographically speaking, where are these lineages distributed?

4. Of the South American, African, and Australian lineages of lungfish, which most closely resembles the ancestral Devonian form? In what ways do they share a resemblance with Devonian sacropterygians?

5. How do these three groups of lungfish differ in terms of their reliance on air-breathing? Describe two important adaptations of lung fish; one relating to feeding, and the other to tolerating drought/avoiding dessication.

6. When was the first living coelacanth specimen discovered? Which two people are most noted for describing it? Where was it discovered? Where else have living specimens been found since?

7. Describe an unique feature of coelacanth breeding biology.

8. Which group of bony fishes has experienced the largest radiation? Describe two (of four presented in lecture) ancestral, and one (of two presented) derived features of extinct Paleoniscids.

9. List the major Actinopterygian lineages (common names are fine), in order from most ancestral to most derived, along with al least one defining characteristic for each lineage.

10. Briefly describe ancestral and derived conditions of bony fish jaw structures, with examples of groups that possess them, in terms of degree of upper jaw fusion with skull and mobility. What are some advantages to the derived condition?

11. In which of these two African Rift Valley lakes (Victoria or Tanganyika) have cichlids diversified in terms of BOTH jaw structure and body shape? What feeding type is the ancestral cichlid presumed to be?

12. What are “species flocks”? How was speciation initiated in the species flocks seen in class (divergence in body shape, feeding morphology, or evolution of color pattern differences through sexual selection)?

Lecture 6 (12 September 2013)

1. Describe three features (of several discussed in lecture) that different lineages of deep sea fishes have converged upon, and explain their adaptive significance (i.e., how they are important to the organism’s fitness; what types of pressures might have selected for them). In what sense do deep sea fishes provide a counter-example to the African cichlids?

2. Which physical property of water allows for the presence of life in the ocean depths?

3. Describe the reproductive biology of the Anglerfish. Why this extreme form of sexual dimorphism is so unique to this group?

4. Describe some differences in gill structure and function among lampreys, sharks, and teleosts, in terms of (a) their support structures (or lack thereof), and (b) how they are aerated (i.e., water flow). Describe the role of the operculum in teleost respiration.

5. Explain the “two pump” system of teleost respiration; what are the pumps, and how do they work? What were the adaptive consequences of this innovation?

6. Describe the counter-current exchange mechanism of gill function; how does it work and what makes it so efficient?

7. To which life trait of fish is the relative gill surface area related to? Explain why.

8. What is a “swim bladder” and which structure is it derived from? What did it initially evolve for, and what was it secondarily co-opted for in some fish?

9. Describe the two types of swimbladders, and indicate which is ancestral and which is derived. Briefly explain how each functions.

10. In which types of habitats is schooling behavior more prevalent? In what type of fish (nocturnal or diurnal) does schooling generally occur? Why? How do fish monitor the movements of others?

11. List two main advantages to schooling behavior, and for each provide at least two lines of reasoning, complete with examples form the lecture, videos, or text. Explain the composition and significance of single- and multi-species schooling groups.

12. List the disadvantages of schooling behavior and how they may be overcome for the benefits.

Lecture 7 (19 September 2013)

1. Which are the two main fertilization strategies found in fish? What is the major difference between the two types? Contrast group and pair spawners, particularly in terms of the relative costs and benefits (i.e., trade-offs) associated with each.

2. Give an example of a group characterized by internal fertilization, and describe the relevant structure(s) involved.

3. Name two types of eggs laid by fish, and describe them in terms of where they are laid, and their advantages and disadvantages. Provide an example for each.

4. What is sex-role reversal? Describe an example in fishes.

5. Explain the resource defense mating system. Describe the resource defense mating system of three-spine stickleback, in terms of what constitutes the limited resource, what males fight for, and what kinds of evolutionary implications this has for the physical features of males.

6. Describe some of the strategies used by fish to protect their offspring from predators.

7. Explain the difference between parental caregivers and cuckolders in bluegill sunfish. When does each male form sexually mature relative to females? What are the two types of cuckolders, and what is the difference between them?

8. Discuss the pros and cons of providing parental care. Specifically which are the advantages and disadvantages of this behavior by male fish reviewed in class?

9. Honest signals are traits that provide a potential mate with an estimation of the overall potential parter quality. Provide an example of this discussed in class.

10. What is a lek? Provide an example from the lecture, videos, or text.

11. Describe the trade-off (or evolutionary cost/benefit) in some species that results from strong sexual selection on male coloration.

12. Describe sex change in the blue-headed wrasse, in terms of females, primary males, and secondary males. How long does it take to go from female to male?

Lecture 8 (24 September 2013)

1. What is a tetrapod? When did tetrapods first invade land?

2. What is Pangaea? When did it form? How, and why, was the climate different in northern continents, such as Greenland where some of the most important early tetrapod fossils were found?

3. By when were the major lineages leading to amphibians, and also to reptiles & mammals established, and what are these two early clades called?

4. Eusthenopteron was considered a close relative of tetrapods; what is it that makes it more a fish with tetrapod features, rather than a tetrapod with fish features? In the 1990s Panderichthys became the favored tetrapod ancestor; what made this specimen more tetrapod-like?


Answer the following "who, what, when, where, why, how" questions for each of the following questions:

5. ACANTHOSTEGA

What is it?

When (in evolutionary time)?

Where (geographically, and habitat-wise) was it found?

Why is it considered a transitional fossil between fish and tetrapods?

List its fish characteristics and its tetrapod characteristics.

6. ICHTYOSTEGA

What is it?

When (in evolutionary time)?

Where (geographically, and habitat-wise) was it found?

Why is it considered a transitional fossil between fish and tetrapods?

List its fish characteristics and its tetrapod characteristics.

7. TIKTAALIK

What is it?

When (in evolutionary time)?

Where (geographically, and habitat-wise) was it found?

Why is it considered a transitional fossil between fish and tetrapods. List its fish characteristics and its tetrapod characteristics?


8. When and where was Tiktaalik discovered? In what ways is this specimen more tetrapod-like than Panderichthys, but still a true fish-tetrapod intermediate?

9. What is the significance of the finding that Acanthostega and Ichthyostega have 8 toes? Who made this discovery? When? What are early tetrapod limbs presumed to have evolved for anyways?

10. Where on the vertebrate phylogeny do Tiktaalik, Acanthostega, and Ichthyostega map out?

11. To which two major tetrapod groups do Eogyrinus and Chroniosuchus belong to? What are Carboiniferous tetrapods considered non-amniote tetrapods rather than amphibians? When did the Carboniferous tetrapods become extinct?

12. What makes Crassigyrinus particularly interesting from an evolutionary standpoint? What are the Microsaurs, and which modern groups are they most similar to? What did these early tetrapods eat?

EXAM 1 (26 September 2013)



Lecture 9 (1 October 2013)

1. List the three synapomorphies that unite all amphibians.

2. What are the three major groups (classes) of amphibians? Provide some characteristics of each.

3. Name at least two fossil amphibians. When do they date back to? Where were they discovered?

4. Define paedomorphosis. In what major group of amphibians would you likely encounter this? What is the difference between facultative paedomorphosis and obligate paedomorphosis?

5. List at least three characteristics that distantly related cave-dwelling salamanders have converged on.

6. What are some differences in morphology between semi-aquatic frogs, treefrogs, hopping/walking frogs, and primarily aquatic frogs?

7. What two types of glands do all amphibians have in their skin? Additionally, what is another type of gland that may be found in some amphibian species that inhabit dry environments? Provide some functions of each gland type.

8. How do some amphibians prevent evaporative water loss when living in harsh (i.e., dry) habitats? Who has more water-permeable skin, a leopard frog (a semi-aquatic frog) who has steady access to water or a spadefoot toad that lives in the desert?

9. Match the following groups with their respective types of fertilization: A) most frogs, B) most salamanders, and C) caecilians: 1) internal fertilization, no copulatory organ; 2) internal fertilization w/ copulatory organ, 3) external fertilization. What is the difference between direct and indirect internal fertilization.

10. List the four basic modes of salamander reproduction.

11. What is parental care? Which major groups of amphibians exhibit parental care? How does parental care differ between these groups?

12. Provide an example of an exception for each of the following rules: 1) Most salamanders have internal fertilization. 2) Most frogs have external fertilization.

13. Are reproductive modes more diverse in anurans or salamanders? Explain. What is the ancestral mode of reproduction in frogs?

14. Explain why males of many amphibians posses traits that make them more conspicuous.

15. Describe the three different kinds of mating systems of salamanders, and provide an example for each. Which mating system is characteristic of the most sexually dimorphic of all salamanders?

16. Explain what a resource defense mating system is, and which groups (and/or species) exhibit it. How does this differ from non-resource based systems? Give an example of such a system, and explain how it works.

Lecture 10 (3 October 2013)

1. By the Devonian, which two major tetrapod clades were established? Explain which group the Seymouriamorphs fall under, and list a few of their characteristics. What were the Diadectomorphs?

2. When did the first amniotes likely arise? When does the first evidence of the amniotic egg appear? What are the three distinct lineages of amniotes? What are their defining characteristics? Which groups are ultimately derived from each of these lines?

3. Were anapsids more diverse in the Carboniferous, or in the Cenozoic? What type of anapsid currently exists? When did diapsids first appear, and what were they like?

4. How do tuataras differ from other lepidosaurs? What are the three major groups of squamates? Does the term lizard refer to a monophyletic grouping? Why or why not?

5. What mode of fertilization do all squamates have? How is fertilization achieved? Describe an advantage of this form of fertilization. (Note: this form of fertilization may result in multiple paternity; what other mode of fertilization (in which other group) may also result in multiple paternity?).

6. What is an amniotic egg? List its basic components. Explain some differences in egg shell characteristics among crocodilians, turtles and lepidosaurs, in terms permeability of shell to water and albumin reserves. How does water uptake affect embryonic mass in some groups? Provide examples.

7. In which kinds of environments are hard vs. soft-shelled eggs laid? Why? What implications does this have for offspring fitness? Explain how water uptake, temperature, and the amount of yolk used up by the embryo are related in snapping turtles.

8. Why don’t all reptiles lay rigid-shelled eggs that can survive dry conditions? What are “parchment-shelled” eggs, and where might you find them?

9. What is temperature-dependent sex determination? Which groups does it occur in? What temperatures (hot/cold) determine which sex (male/female) in each group?

10. List four major mating systems exhibited by squamates, and provide an example for each. Which type(s) of mating systems are more characteristic of Iguanian lizards? Sceroglossine lizards?

11. Explain the difference between female-defense and resource-defense mating systems in lizards? Give an example of a group that exhibits the former. In which other groups have we seen these types of mating systems?

12. In which group of lizards has the tongue been freed to evolve functions other than feeding? Explain how has this been facilitated, and give an example of such a function. Describe the typical mating system of scleroglossans.

Lecture 11 (8 October 2013)

1. What is the most diverse group of squamates?

2. Reduction or loss of limbs is a common evolutionary theme in squamates. Which is the most diverse group of limbless squamates? Which characteristic of the jaws has lead to this group’s great success?

3. Give an example of how body forms of lizards are correlated with variation in ecology. Give an example of convergent evolution in lizards.

4. Describe some adaptations for arboreality in chameleons.

5. How does body size relate to general diet in lizards? Explain why monitor lizard feeding behavior is unusual.

6. Explain how surface-active and fossorial legless forms of lizards differ in other aspects of morphology. Which are the “most specialized burrowing legless reptiles”? What about them makes them so?

7. From which clade of squamates are snakes derived? What implications does the elongate body of snakes have for other organs?

8. What do snakes use their tongues for? How does the snake tongue work?

9. Describe some adaptations of snakes for feeding on relatively large objects (e.g., egg, goats). How do generalized terrestrial snakes tend to kill their prey? What kinds of physical features do active terrestrial foragers tend to possess? What about highly arboreal forms? What about vipers?

10. Name and briefly explain five types of snake locomotion.

Lecture 12 (10 October 2013)

Lecture 13 (15 October 2013)

Lecture 14 (17 October 2013)

Lecture 15 (22 October 2013)

Lecture 16 (24 October 2013)

Lecture 17 (29 October 2013)

EXAM 2 (31 October 2013)



Lecture 18 (5 November 2013)

Lecture 19 (7 November 2013)

Lecture 20 (12 November 2013)

Lecture 21 (14 November 2013)

Lecture 22 (19 November 2013)

Lecture 23 (21 November 2013)

Lecture 24 (December 3, 2013)

Lecture 25 (December 5, 2013)




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