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Invertebrate Paleontology These questions will be either taken from your textbook, previous lecture material, or the Web. I will expect you all to have written down brief answers in the spaces below. During the appropriate lectures I will call on students to answer the questions. Occasionally I will ask for all the papers of a particular day to be turned in to be graded as quizzes. August 30, 2007 (Thursday) 1. What is a type specimen or holotype? What is the value of a type specimen system in paleontology and biology? We will talk in class about the typological philosophy in systematic biology and paleontology, but you can start thinking “Plato” now. 2. We are not going to spend much time in the debates between cladistics and phenetics (and other classification systems), but these terms are useful: monophyletic, polyphyletic and paraphyletic. Very briefly, what do they mean? Nice little labeled family tree diagrams would be useful as answers.
September 4, 2007 (Tuesday) 1. How does chemosynthesis differ from photosynthesis as a metabolic pathway? 2. What do we mean when we say a marine organism is a sessile benthic infaunal filter-feeder? 3. What is the carbonate compensation depth? (Sed/Strat veterans can fly with this one.) How is it an issue for invertebrates living in the oceans?
September 6, 2007 (Thursday) 1. Please think of reasons why a shell (called a test in foraminiferans and some others) made of silica may have some advantages in the sea over one made of calcium carbonate. 2. Why would radiolarians be more common in many deep-water marine sediments than planktonic foraminiferans? 3. What are the morphological differences between a microspheric foraminiferan and a megalospheric (not “megaspheric” as in your text) foraminiferan of the same species? Why do we have such differences within a species?
September 11, 2007 (Tuesday) 1. I used to keep them within their own separate phylum, but now I go along with most paleontologists and place the extinct archaeocyathids (archaeocyatha, archaeocyathans) with the sponges (Phylum Porifera). Time for you to do a little web research and tell me why these mysterious conical creatures were likely sponges. Give me an argument based on their skeletal features and probable functional morphology.
September 18, 2007 (Tuesday) 1. What single feature characterizes all members of the Phylum Cnidaria? 2. Please briefly distinguish between the polyp and medusa in cnidarians. How is the timing of the polyp and medusa stages used to distinguish cnidarian classes? Nice little labeled diagrams will be helpful.
September 20, 2007 (Thursday) 1. What are the differences between hermatypic corals and ahermatypic corals? 2. What are some ways a paleontologist can suggest that particular fossil corals may have had zooxanthellae in their tissues? The tissues are long gone, but there may be some clues left behind.
September 25, 2007 (Tuesday) 1. Brachiopods and clams both have bivalved shells (shells with two parts hinged together). How then do you distinguish a brachiopod shell from that of a clam? (This will be useful for your field collections.) 2. One of the most common brachiopods on our field trip (especially on the second stop) was Rafinesquina, a “concavo-convex strophomenidine”. Prothero cites a living position on page 242 (and fig. 13.14F) which is directly opposite the one I would suggest. What are the issues here in terms of relation to substrate and sediment?
October 2, 2007 (Tuesday) 1. Brachiopods were among the most common marine animals in the Paleozoic with thousands of genera, but now there are only about 120 genera alive, and most of them are rare. What happened? 2. What is an avicularium in some bryozoans? Please draw a simple diagram of one below. What is the function of an avicularium?
October 4, 2007 (Thursday) 1. We’re a bit ahead on preparation questions, so we can quickly review the taxa scheduled for your lab test on Thursday afternoon. Be ready to state the defining features of each group below -- (The orginal on paper looks a lot better with the proper formatting!)
October 9, 2007 (Tuesday) 1. We will use the “Hypothetical Ancestral Mollusk” (HAM) as an introduction to molluscan morphology. Why is it a problem to think of this imaginary creature as a potential ancestor of mollusks? 2. Why did mollusks, particularly clams and snails, play a relatively small role in Paleozoic ecosystems, and then a dominant role in the Mesozoic and Cenozoic? This is related to a previous preparation question!
October 11, 2007 (Thursday) 1. Gastropods (“snails” to the general public) are characterized by a strange embryonic process termed torsion. Please describe below what torsion is: 2. Now please describe what you think is the best explanation for why torsion occurs in the gastropods:
October 18, 2007 (Thursday) 1. Imagine a 10 meter-long straight cephalopod in Ordovician seas. How did it move through the water? What did it likely eat? 2. Ammonoid cephalopods have complex sutures. Please define suture in this context and describe one reason why they may have had such complicated suture patterns.
October 23, 2007 (Tuesday) 1. Rostroconchs have an odd, taco-shaped shell without a hinge. They still had to grow at their shell margins, though. How did they do this? 2. How do scaphopods feed? A diagram may be useful.
October 25, 2007 (Thursday) 1. Maybe this is too easy: How do you distinguish a bivalve shell from a brachiopod shell? After all, they are both made of two opposing calcareous valves. (You’ve already answered this from the brachiopod perspective.) 2. How does a bivalve (member of the Class Bivalvia) open and close its valves? A diagram or two will help.
November 1, 2007 (Thursday) 1. What was the primary ecological pressure on bivalves after the Permian extinctions? Why did bivalves survive under this pressure far better than did the brachiopods? 2. How do some bivalves bore into hard substrates such as rocks and shells? (Hint: the substrates are almost always limestones or calcareous shells.)
November 6, 2007 (Tuesday) 1. Those wonderful arthropods. No doubt they will be our successors as the dominant life forms on this planet. (And they will be succeeded by bacteria!) Let’s start with your own definitions of the following terms --
2. What do we know about the digestive tract of a trilobite? Please draw a simple diagram showing where we think the mouth, stomach, intestine and anus were located. The Web is your friend.
November 13, 2007 (Thursday) 1. What adaptations did the eurypterids have for predation on other less fortunate creatures? 2. Why are the decapods called “decapods”? 3. Describe the primary evolutionary innovation in the winged insects. (When they got their wings – did a little bell ring?)
November 15, 2007 (Thursday) 1. Arthropods are incredibly successful organisms in terms of abundance, diversity and niches occupied. They do not, however, achieve particularly large body sizes (although some spiders are big enough, thank you very much). Why is there this limit on arthropod body size? 2. Tell me what you can about the onychophorans. What do they look like? What is their evolutionary history? We will use them as a starting point to explore the origin and evolution of the Phylum Arthropoda.
November 20, 2007 (Tuesday) 1. How will you recognize a fragment of echinoderm skeleton in thin-section? (As a clue you can look at the third figure on http://www.wooster.edu/geology/hdgd/Jerome.html and figures 1 and 4 here: http://www.wooster.edu/geology/hdgd/Ryan.html) 2. Please list the general trends in the evolution of irregular echinoids, from the Early Jurassic through the Paleocene. What was the driving force behind this evolution? (It will be familiar.)
November 27, 2007 (Tuesday) 1. Why are graptolites particularly good index fossils for Lower Paleozoic rocks? 2. The planktic graptolites mysteriously go extinct by the Middle Devonian. What is a possible reason?
November 29, 2007 (Thursday) 1. On Thursday we begin our section on trace fossils, sometimes called ichnofossils. What is the definition of a trace fossil? 2. What advantages can trace fossils have over body fossils (shells, bones, teeth, etc.) in the study of particular geological sequences?
December 4, 2007 (Tuesday) 1. What is morphospace and how can it be applied to the world of the coiled shell? You will want to distinguish here between potential morphospace and actual (or realized) morphospace. 2. What is an adaptive landscape in the sense of Sewall Wright?
December 6, 2007 (Thursday) 1. These last class and lab sessions will include summary and review of the course. We’ll use the final exam as our focal point. This exam will have three parts: • The third lecture test covering in detail material since the second test. • Summary lecture questions which cover general principles developed in the entire course. -- You will have choices here in the evidence you use to support your answers. • A final lab examination which may include any taxa listed on our yellow sheets. -- You can use the yellow sheets, of course, and anything you’ve written on them. -- This test will include age assemblages, which I will explain in class (as long as you don’t let me forget!). You can use the space below to jot down any questions you have about the final exam. These questions will be our entry into a general review of the course and its materials,
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