Biology of the Vertebrates Study Questions F2011
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.
Contents
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)?
