Biology 332 - Protistology Final Examination 1998

You will have three hours for this examination. Write all answers in the examination booklet. PUT YOUR NAME ON THE FRONT OF THE EXAM BOOKLET.

125 marks total. Use time wisely (25 mark question = 25 min. writing time). You will three hours for this exam.

Here are some words that may help as memory-joggers. They may or may not apply to any of the questions below. Do not go out of your way to invent situations that would enable you to use these terms. They are here to help you remember. amoeboflagellates, bilateria, calcium, ion channels, chloroplast envelope, choanoflagellates, ciliates, colpodids, conjugation, cysts, diatoms, dinoflagellates, DNA repair, feeding-web, foraminifera, fungi, gamogony, gamontocyst, hymenostomes, hyphae, hypotrichs, immaturity, karyotelicta, macrogametocyte, macronuclear anlage, macronucleus, mastigonemes, meiosis, membrane-potential. meregony, microgametocyte, micronucleus, nucleomorph, oligohymenophora, pawn, pennate, phycobillisomes, placozoa, potassium, pseudopodia, raphé, receptor-potential, radiata, receptors, scales, secondary-symbiosis, senescence, sorocarp, spores, sporogony, starch compartment, suctoria, symbionts.

1.(15 marks.) Answer A or B, not both.

Protists show all sorts of adaptations to various environments. This question is about adaptations to benthic (sediment or sediment surface) or terrestrial (soil) environments. Start by making a list of protist groups that have representatives living in 1) benthic and 2) terrestrial environments. Discuss adaptations of the organisms to these environments. What are the major trends (note at least three).

Discuss food vacuole processing in Paramecium. Use experimental observations to support your argument as needed.

2. (20 marks.) Mechanical stimulation produces a specific response in most protists. Explain using studies on Paramecium.

3. (15 marks.) Protists include some of the largest eukaryotic cells. Most eukaryotes have cell diameters from 5 to 20 m m. There are lots of protists with diameters of >100 m m, including many diatoms, some dinoflagellates, euglenoids apicomplexans and many ciliates. Discuss adaptations that enable the development of large cell size. Focus your discussion on ciliates and consider other groups by way of comparison.

4. (10 marks). Most eukaryotic groups are monophyletic assemblages of organisms. This is not so for amoebae. Explain with examples.

5. (10 marks.) Most protists are immortal. Ciliates are not. Discuss aging and its basis in ciliates in relation to the life history. Consider the role of the nuclei in these processes.

6. (15 marks.) Compare and contrast the life cycles of gregarines and coccidia and discuss the life cycles as adapatations to an endozoic habitat. Start by briefly describing the basic reproductive pattern in apicomplexans and discuss how is this pattern has been adapted by the two major groups of apicomplexans in response to problems associated with life as an endozoic commensal or parasite. Please note that simple description of the life cycles will not constitute an adequate answer to this question.

Write a critique of this tree based on what you know about the phyletic relationships of eukaryotes. Do not forget to consider the title of the article.

Be balanced in your assessments. Consider both placement of groups that you agree with as well as those with which you disagree. Support your argument using your knowledge of protist groups and their properties. In answering this question it is important to consider consistency of traits. Think about the evolutionary sequence of events or the scenarios involved in genesis of the different clades.

8. 10 marks. Background for the question:The availability of reliable procedures for large scale molecular sequencing has revealed many interesting phylogenetic problems. Here is a tree for phosphoglucose isomerase (remember this enzyme from Biol 201?). It occurs in all organisms. In this tree sequences from prokaryotes (bacteria) are indicated by boldface type. Escherichia and Haemophilus . are gram negative endozoic (living in animals) bacteria. All gram negative endozoic bacteria analysed to date fall in this Escherichia, Haemophilus clade. Acinetobacter and Zymomonas are also gram negative bacteria, but are not endozoic. Ribosomal sequence trees place Escherichia and Haemophilus in the same clade with the other gram negative bacteria, in the position occupied by Acinetobacter in this diagram. Each name of a eukaryote group represents a clade of related organisms. Assume that the phyletic positions of these sequences in the tree are accurate. Not all groups of eukaryotes are represented.