Difference between revisions of "Biology of the Vertebrates Study Questions F2011"

Revision as of 18:50, 6 October 2011

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 (30 August 2011)

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

2. Which major taxonomic group of vertebrates is the most speciose? The least? What might account for these differences in numbers of species? Roughly what fraction of animals do vertebrates comprise?

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

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

5. List at least four character types used to reconstruct phylogenies. Provide an example of a bad character to use when reconstructing the evolutionary history of an organism.

6. What is the evolutionary significance of Pikaia?

Lecture 2 (1 September 2011)

1. Describe three major evolutionary trends in the vertebrate body plan.

2. List, and briefly describe, each of the major organ systems shared by vertebrates.

3. What are ‘homologous’ bones? Provide an example.

4. 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.br>

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

5. Describe the three major embryological regions of the skull, and what each gives rise to. 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. What is paedomorphosis? Please provide an example of a paedomorphic vertebrate.

Lecture 3 (6 September 2011)

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 life 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?

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 hetercercal tails – what does this mean?

6. Which group of ostacoderms is characterized as having brain structures similar to lampreys?

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

8. List the six main gnathostome (jawed animal) characteristics. Roughly when did jaws evolve? Briefly explain Mallatt’s hypothesis regarding the evolution of jaws from jawless, filter-feeding ancestors.

9. List the four main gnathostome groups present between the Silurian and Devonian. Describe some of the major characteristics of placoderms, and how they differ from the ostracoderms.

Lecture 4 (8 September 2011)

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

2. How do modern sharks differ from their ancestral counterparts (give at least three major characteristics)? When in geologic time did cartilaginous fishes arise?

3. 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?

4. 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).

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

Lecture 5 (13 September 2011)

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. What happened to all the other jawed and jawless vertebrate lineages during the radiation of the sarcopterygians?

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

5. 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? How do these three groups 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? What are “species flocks”? How was speciation initiated in these species flocks (divergence in body shape, feeding morphology, or evolution of color pattern differences through sexual selection)?

Lecture 6 (15 September 2011)

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. 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.

3. 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?

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

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

6. 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?

7. 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.

Lecture 7 (20 September 2011)

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. 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.

5. 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?

6. What is a lek? Provide an example from the lecture, videos, or text. Describe the trade-off (or evolutionary cost/benefit) in some species that results from strong sexual selection on male coloration.

7. 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 (22 September 2011)

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?

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

6. 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?

7. 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?

8. What makes Crassigyrinus particularly interesting from an evolutionary standpoint? What are the Microsaurs, and which modern groups are they most similar to?

9. What did these early tetrapods eat?

Lecture 9 (27 September 2011)

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. What are the diets of a larval caecilian, a larval salamander, and a tadpole? Now, what are the diets of an adult caecilian, an adult salamander, and an adult frog? What are two ways in which an adult amphibian acquires its food?

10. What is an explanation to why are there no paedomorphic tadpoles, while nice of ten salamander families have paedomorphic representatives? Provide a few adaptations of tadpoles mouthparts that are correlated with their feeding habits.

EXAM 1 (29 September 2011)

Lecture 10 (4 October 2011)

1. 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.

2. List the four basic modes of salamander reproduction.

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

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

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

6. Describe five different egg deposition strategies in frogs.

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

8. 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?

9. Describe explosive breeding seasons and scramble competition, and indicate which groups of amphibians experience these. When possible, provide examples.

10. 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 11 (6 October 2011)

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? Which two distinct lines of amniotes were established by the end of the Carboniferous? What were 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. 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?

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

9. 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?

10. 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?

11. 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.

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