DO NOT OPEN EXAM UNTIL INSTRUCTED TO DO SO

Name: Last KEY First ID# Lab. Date and Time Lab. TA Biological Sciences 1B Dr. Herrlinger Summer Sessions I 2000 Midterm 2 July 21, 2000 DO NOT OPEN EXAM UNTIL INSTRUCTED TO DO SO Multiple Choice Questions Please Read the Instructions First Check your pages. There are 11 pages in this exam. You are responsible for making sure that you have all the pages. This examination is worth 85 points. Write your name, ID#, and Lab. Section on your scantron. 1. Indicate your answers on the scantron sheet using a number 2 or test scoring pencil. Press heavily, don t stray out of the margins, and completely erase any changed answers. 2. If you think that a multiple choice question is ambiguous or confusing, use the gripe sheet at the end of the examination to explain the problem. 3. There are 30 multiple choice questions worth 2 points each. Fill-in Questions 1. Use pen only (no grade corrections for pencil or white out). 2. Write only one answer per question. You can elaborate on an answer, but you will not be given any credit if you write two different answers to the question. 3. Spelling rules: ½ credit for 2 3 letters wrong or transposed. No points will be given if the misspelling alters the meaning of the word. 4. There are 11 fill in questions worth 25 points in total. 1

Choose the one best answer: 1. Which statement best characterizes the coelom in the following groups? A. It is greatly reduced in the annelids. B. It is greatly reduced in the cnidarians. C. It is intermediate in the flatworms. D. It is reduced in the arthropods. E. It is well developed in the molluscs. 2. Which phyla show relatedness based on a common larval form? A. Annelida and Arthropoda B. Annelida and Mollusca C. Arthropoda and Mollusca D. Cnidaria and Porifera E. Platyhelminthes and Annelida 3. Since house flies lay eggs which turn into maggots (small, white, writhing larvae) before developing into an adult fly, you conclude that A. the adult must have biting mouthparts B. the larva has heteronomous segmentation C. the terminal stage exhibits a cephalothorax D. they undergo hemimetabolous metamorphosis E. they undergo holometabolous metamorphosis 4. The claw like appendages in scorpions are A. acidic B. biramous C. chelicerae D. modified antennae E. pedipalps 5. Which of the following taxa contain species with a true coelom? A. Cestoda B. Oligochaeta C. Porifera D. Scyphozoa E. Turbellaria 2

Porifera Cnidaria Platyhelminthes Annelida Mollusca Arthropoda S T Q R O P M N K L J Using the principle of parsimony, examine the phylogeny above (modified from Knoll and Carroll, 1999) to answer the questions on this page. 6. Where did the triploblastic condition first arise? A. J B. L C. N D. O E. P 7. Where should schizocoelous formation of the coelom be placed? A. J with two losses on the phylogeny B. L with one loss on the phylogeny C. N with no losses on the phylogeny D. R and P with no losses on the phylogeny E. S and P with no losses on the phylogeny 8. Where should the presence of a trochophore larva be placed? A. N B. O C. R D. S and P E. T and P 3

9. In which organisms does the blastopore become the mouth of the developing individual? A. all deuterostomes B. all deuterostomes except chordates C. all organisms with a complete gut D. all protostomes E. C and D 10. Which of the following generalizations about annelids is true? A. leeches have no setae B. oligochaetes have few setae C. polychaetes have many setae D. all of the generalizations above are true E. none of the generalizations in A C are true 11. Insects have developed a close association with plants. Which of the following is NOT a true statement about plant insect interactions? A. An insect s choice of flowers can affect pollen distribution. B. Co evolution between insects and plants involves pollination biology and insect feeding. C. Most insects are parasitic. D. Plants can influence the timing of different stages of an insect s life cycle. E. Some orchids produce chemicals that attract male wasps. The wasp copulates with the plant and transfers pollen to another orchid. 12. A small anthozoan polyp that buds off the main polyp A. can capture prey with its own tentacles B. is colonial while still attached to the main polyp C. is genetically identical to the main polyp D. is undergoing asexual reproduction 13. Which of the following is a true statement for the phylum Cnidaria? A. Examples of polymorphic hydrozoans are sea pansies and sea pens. B. Hydroids lack the medusa stage. C. The planula larva is present in all four classes of cnidarians. D. The Portuguese Man O War is a scyphozoan and the float is a modified medusa. E. The Scyphozoa are monoecious. 4

14. If I had an eight legged arthropod with chelicerae in my hand, what animal could it be? [Hint: It doesn t have a telson.] A. a branchiopod B. a horseshoe crab C. a lobster D. a spider E. a wasp 15. Sponges in the Class Calcarea secrete calcium carbonate spicules. Which cnidarians have numerous members that make calcareous structures? A. anthozoans B. cubozoans C. hydroids D. jellies 16. Recall the Principle of Continuity. If the combined cross sectional diameter of all the incurrent pores in a sponge is twice that of the cross sectional area of its single, large osculum, what can be said of the water exiting the osculum? A. It should be sufficient to expel filtered water far away from the sponge. B. It will likely dribble out. C. It will exit the osculum at half the speed it entered the incurrent pores. D. The exit velocity depends on the number of spicules inside the sponge. E. The exit water will not be properly filtered because it will move too slowly over the choanocytes. 17. Which of the following is a true statement about the box jelly (Chironex fleckeri) that is responsible for numerous deaths in Australian waters? A. It is a true jelly in the Class Scyphozoa. B. It is triploblastic and an exception to the other classes of cnidarians. C. Its sting is caused by cnidae that contain vinegar. D. Its venom can be inactivated by vigorously rubbing sand on the affected area. E. The nematocysts can still fire even when the animal is out of the water. 18. The coelom in annelids A. develops by enterocoely B. doesn t exist C. forms from the mesoderm D. is derived from the archenteron E. is derived from the blastocoel 5

19. Two cross sections of an earthworm gut are shown above. The gut cavity is represented in white. Section 1 was taken at a level anterior to the crop and section 2 was taken through the intestine. Which of the following statements is true? A. The gut region in Section 1 has more internal surface area than the gut region in Section 2. B. The gut region in Section 2 has more internal surface area than the gut region in Section 1. C. Nutrient absorption is likely to be greater in Section 1 than in Section 2. D. A and C E. B and C 20. Parasitic flatworms A. are pseudocoelomates B. have an open circulatory system C. have elaborate sense organs D. make an enormous investment in reproduction E. B and D 21. A hydrostatic skeleton would be characteristic of which of the following taxa? A Crustacea B. Hydrozoa C. Polychaeta D. Porifera E. B and C 22. Barnacles are members of the Phylum and have what type of larva(e)? A. Arthropoda; nauplius B. Arthropoda; nauplius and cyprid C. Arthropoda; trochophore D. Crustacea; nauplius E. Mollusca; trochophore 23. Members of the Class Trematoda A. are commonly called tapeworms Section 1 Section 2 6

B. are dioecious C. form large colonies D. have only a single host in their life cycle E. produce several different body types asexually 24. Which of the following is a true statement about the Phylum Mollusca? A. All gastropods go through torsion. B. All molluscs have a radula. C. Most gastropods can change sex. D. Terrestrial gastropods retain the ctenidia. E. The ammonites are an extant group of cephalopods. 25. The arthropod exoskeleton A. has waxy, water repellent molecules pointing to the inside in terrestrial arthropods B. is a hard, non living covering C. is made of chitin D. is strengthened in marine arthropods by the addition of calcium salts 26. Cephalopods can change their appearance by A. producing bioluminescence B. contracting or expanding pigments in chromatophores C. altering the texture of their mantle tissue D. hiding and covering themselves with sand or shell debris 27. Which letter contains only members of the same Subphylum? A. ants, centipedes, millipedes, spiders, wasps B. barnacles, hermit crabs, isopods, krill, shrimp C. beetles, cockroaches, fleas, moths, ticks D. daddy longlegs, horseshoe crabs, house flies, mites, mosquitos E. honey bees, lady bugs, millipedes, scorpions, tarantulas 7

28. The circulatory system of cephalopods is more efficient than that of other molluscs because A. cephalopods can breathe air B. it has five hearts C. it has true blood D. it is closed 29. Gas exchange in the earthworm occurs through the A. clitellum B. gills C. lungs D. setae E. entire skin 30. Leeches A. are entirely parasitic B. have anterior and posterior suckers C. have few setae D. lack a clitellum 8

Matching Choose the letter(s) that best correspond(s) to each question. Letters may be used more than once and multiple answers are required for some questions. You must list all appropriate letters to receive any credit for the question. No partial credit. (2 pts each) A. Annelida B. Arthropoda C. Cnidaria D. Mollusca E. Platyhelminthes F. Porifera 31. development ends at the blastula stage F 32. development ends at the gastrula stage C 33. spiral cleavage A, B, D, E 34. complete gut A, B, D 35. no coelom C, E, F Short Answer 36. Choanocytes are totipotent. Other than filter feeding, name another function of a choanocyte. (2 pts) Choanocytes also act as sperm carriers. [They capture sperm, lose their flagella, and migrate to the ova.] 37. Define the term monoecious (don t just give a synonym). Give the taxonomic name of three Classes whose members are all (or mostly) monoecious. (4 pts) monoecious organisms have both male and female gonads in the same individual Classes: Calcarea, Hexactinellida, Demospongiae, Sclerospongiae, Turbellaria, Trematoda, Cestoda, Monogenea, Oligochaeta, Hirudinea 9

38. The ancestral flatworm is believed to have been free living. a. Describe one feature of the ancestral flatworm morphology and/or life style and how it would have enabled the ancestral flatworm to evolve into successful groups of parasites. (2 pts) sucking pharynx the parasite could suck nutrients from the host while attached blind gut since the food of a parasite is pre digested this would not be a problem monoecious reproduction a parasite inside a host could undergo self fertilization b. Describe one feature of the morphology of the ancestral flatworm and how it would present a problem for a change to a parasitic life style. (2 pts) ciliated epidermis living in the tissue or gut of a host, the parasite would be vulnerable to attacks by the host s immune system. If the parasite lives in the gut of the host, it would have to avoid being digested. 39. Draw and label the complete generalized life cycle of a coral. (2 pts) Adult polyp! zygote!planula larvae (and back to the adult polyp) 40. If there are no individual segments in the molluscan body, is there evidence for more than one pair of repeated elements? If so, list the name of one class, one structure, and the number of repeated elements involved. (2 pts) Class Monoplacophora 8 pairs of muscles, 5 6 pairs of ctenidia, 2 pairs of gonads, 6 7 pairs of excretory organs (metanephridia). Class Polyplacophora 8 dorsal shell plates, 6 80 pairs of ctenidia [Also accepted Class Cephalopoda 8 arms/tentacles (octopuses, squid, and cuttlefishes have 8 arms; squid and cuttlefishes also have 2 tentacles; nautiloids have tentacles] 41. Following torsion in gastropods, which organs and how many of them were lost? (1 pt) one ctenidium one kidney one auricle 10

Name: Last First ID# Gripe Sheet Instructions: 1. Put your name at the top of the page (I tear it off from the rest of the exam). 2. If you think that a question is ambiguous or confusing, indicate the question number, the answer you gave, and the reason that you gave this answer. Question # Answer you gave Gripe 11