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MAB701S - MARINE BIOLOGY 3A - 1ST OPP - JUNE 2023 |
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nAmlBIA UnlVERSITY
OF SCIEnCE AnDTECHnOLOGY
FACULTYOF HEALTH,NATURALRESOURCESAND APPLIEDSCIENCES
SCHOOLOF NATURALAND APPLIEDSCIENCES
DEPARTMENT OF BIOLOGY,CHEMISTRYAND PHYSICS
QUALIFICATION: BACHELOROF SCIENCE
QUALIFICATION CODE:07BOSC
COURSECODE: MAB701S
SESSION:JUNE 2023
DURATION: 3 HOURS
LEVEL:7
COURSENAME: MARINE BIOLOGY 3A
PAPER:THEORY
MARKS: 100
EXAMINER (S):
MODERATOR:
FIRSTOPPORTUNITY EXAMINATION PAPER
Dr. Edosa Omoregie
Dr. Johannes litembu
INSTRUCTIONS
1. Answer all questions in Sections A, Band C
2. Write clearly and neatly.
3. Number your answers correctly.
PERMISSIBLEMATERIAL
Calculator
THIS QUESTION PAPERCONSISTSOF 4 PAGES
(Including this front page)
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SECTION A
Answer all questions
Total marks [15]
1. The diagram below illustrates a common intertidal organism collected from the Namibian
coast
i. State the Class and Phylum the organism belongs to?
(2)
ii. Explain the main reason for placing the organism under its Class?
(3)
2. Name the parts labelled in the diagram below. Briefly explain the functions of the part
labelled as D, E and F.
(6)
3. The sea anemones belong to which of the following classes of marine animals?
(1)
a. Hydrozoa
b. Scyphozoa
c. Anthozoa
d. Calcarea
e. Hexactinellida
4. Which of the following pigments is predominant in the seaweed Phylum, Phaeophyta? (1)
a. Chlorophyll
b. Phycobilin
c. Fucoxanthin
d. Carotenes
e. Flavoxanthin
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4. Which of the following phyla do the barnacles belong to?
(1)
1. Annelida
2. Echinodermata
3. Mollusca
4. Arthropoda
5. Cnidaria
5. Which of these groups of marine molluscs belong to Class Bivalvia?
(1)
a. Octopuses, Squids, Nautilus
b. Clams, Mussels, Oysters
c. Snails, Abalone
d. Slugs, Periwinkles
SECTION B
Answer all questions
Total marks [40]
6. With an appropriate schematic diagram, describe the different zones along the
substratum of the marine ecosystem.
(5)
7. Briefly explain the factors that affect Secchi disc depth (zscto) f water in the marine
environment.
(4)
8. Briefly explain the diurnal distribution of dissolved oxygen in the marine environment
with a suitable graphic illustration.
(6)
9. With graphical representations, briefly explain the vertical variation patterns of
phosphates in an oligotrophic and eutrophic aquatic system.
(7)
10. In a tabular form, outline the main differences between marine Coccolithophores and
Silicoflagellates.
(8)
11. With a suitable example, explain any two characteristics of the marine cephalopods. (4)
12. In a tabular form, outline the main structural differences between marine diatoms and
marine dinoflagellates.
(6)
SECTION C
Answer all questions
Total marks [45]
13. (a). Name any three products of anoxic decomposition in the marine ecosystem.
(3)
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(b). With the aid of the glycolytic partway and the tricarboxylic acid cycle, discuss the
process of oxic decomposition in the marine environment.
(12)
14. (a). With reference to the life cycle and suitable examples, differentiate holoplankton
from meroplankton.
(4)
(b) Briefly explain the general characteristics and structure of marine macroalgae. (8)
(c). List the three predominating pigments in the green, brown and red algae.
(3)
15. With suitable diagrams, discuss how the elasmobranch and the teleost regulate their body
osmotic pressure in conforming to living in the marine environment.
(15)
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