The University of Queensland
BIOL2204 Zoology
Practical 1 (Revision Questions & Answers)
1. Under a microscope, you observe a discrete green organelle within a protist. What might
this organelle be, and what is its function? (plastid/chloroplast – contains chlorophyll to
harvest energy from the sun through photosynthesis)
2. How do protists move? (some are non-motile and ‘go with the flow’, others have cilia or a
flagellum)
3. Name one organelle that autotrophs and heterotrophs would have in common.
(mitochondria, nucleus)
4. How many classes of sponges are there? (four)
5. How are the classes of sponges differentiated? (using the spicules to identify which class)
6. True or False – the class Homoscleromorpha separated from the class Calcarea. (False – they
separated from the Demospongiae)
7. True or False – the class Hexactinellidae is characterised by its members having 6 rayed
siliceous spicules. (True)
8. What cell type is the basic functioning unit of sponges? (choanocyte/collar cell)
9. Siliceous spicules have a re-enforcing function and so need to be bound together. Name two
ways in which these spicules bind. (spongin (= in Demospongiae) or a trabular net (= in
Hexactinellidae))
10. What sort of biological symmetry would you use to describe sponges, and in what stage of a
sponge’s life history is this form of symmetry most obvious? (radial symmetry, larval stage)
11. What are ostia? (pores in a sponge where water enters, osculum is where water exits)
12. True or False – sponges have the genes for a nervous system. (True – but these genes are
not functioning)
13. How do sponges reproduce asexually? (buds or gemmules)
14. How do sponges reproduce sexually? (eggs and sperm; free-swimming flagellated larvae in
most)
15. What is the defining characteristic/feature of a cnidarian? (cnidocytes, which house
nematocysts)
16. Name the two growth forms of a cnidarian. (polyp and medusa)
17. How many germ layers do cnidarians have? Name them. (two – embryonic ectoderm to
epidermis and embryonic endoderm to gastrodermis)
18. What is the ‘jelly’ between the body layers of cnidarians called? (mesoglea)
19. Name the two forms of digestion undertaken by cnidarians (extracellular digestion in
gastrovascular cavity and intracellular digestion in gastrodermal cells/symbioses with
dinoflagellates)
20. When you touch a cnidarian, you can sometimes observe it making muscular contractions.
Which cell type is responsible for these movements? (epitheliomuscular cells/contractile
cells)
21. Name the sense organ of balance. (statocyst)
22. Name the sense organ of photosensitivity. (ocelli)
23. What sort of nervous system do cnidarians have? (nerve net)
24. True or False – Cnidarians do not possess true epithelia (False – true epithelium is present,
it is one cell thick but they do have fibrous basal membrane)
Other tips
1. Ensure you know how to briefly draw an asconoid and syconoid body plan. You must include
the flow of water current.
2. Ensure you know how to draw a choanocyte.
Prepared by Gurion Ang, Semester 2, 2015
The University of Queensland
BIOL2204 Zoology
Lab Quiz
AM Session
1. What organelle do you specifically find in a phototrophic protist? (plastid/chloroplast = 2
marks, chlorophyll = 1 mark)
2. What cells generate water currents in sponges? (choanocytes/collar cells = 2 marks)
3. Draw a schematic diagram of an asconoid sponge. (2 marks, you will lose marks if the labels
were absent or inaccurate)
4. What are the two body forms that occur in Cnidaria? (polyp and medusa = 1 mark each)
5. From which feature do cnidarians get their name and what is its function?
(cnidocytes/nematocysts = 1 mark, stinging cells = 1 mark)
PM Session
1. What organelle should you find in most protists? (nucleus/mitochondria = 2 marks,
flagella/cilia = 1 mark, plastid/chloroplast = 0 marks)
2. Draw and label the key features of a choanocyte. (2 marks, you will lose marks if the labels
were absent or inaccurate)
3. In which group of animals do you find spicules and what is their function? (sponges = 1
mark, protection/structural = 1 mark)
4. If Cnidaria are diploblastic, name the two germ layers present in embryogenesis.
(ectoderm/epidermis and endoderm/gastrodermis = 1 mark each)
5. Name a sense organ found in hydrozoan medusa and state its function. (ocelli for
photosensitivity / statocysts for balance = 1 mark for organ and 1 mark for correct
function)
Prepared by Gurion Ang, Semester 2, 2015