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DEPARTMENT OF BIOLOGICAL SCIENCES SEPTEMBER 2018
CLASS TEST 1 TIME: 50 minutes BIO1004S (BIOLOGICAL DIVERSITY) TOTAL MARKS: 40 This test paper has two sections. Answer both sections. SECTION A: MULTIPLE CHOICE QUESTIONS (20 MARKS) ONLY use an HB pencil for filling in the Multiple Choice Answer Sheet. Fill in your name and student number on the MCQ Answer Sheet supplied. Provide the most correct answer to each question. Negative marking does not apply to this section and unanswered questions are not penalized. Use a soft eraser to carefully rub out incorrect answers. Enclose the MCQ Answer Sheet in the Answer Book before handing in. QUESTION 1
Natural selection acts on:
a) Populations
b) Species
c) Lineages
d) Individuals
e) Generations
Answer (d)
QUESTION 2
Natural variation is:
a) Random
b) Non-random
c) Not necessary for evolution
d) Only found in sexually reproducing organisms
e) Only found in asexually reproducing organisms
Answer (a)
QUESTION 3
Sexual selection is selection:
a) On traits that are advantageous for survival
b) On traits that are advantages for reproduction
c) On sexually reproducing organisms
d) On asexually reproducing organisms
e) Mediated by male choice of female partners in most animals
Answer (b)
QUESTION 4
Adaptation is a consequence of
a) Random genetic drift
b) Founder effect
c) Natural selection
d) Gene flow
e) Variation
Answer (c)
QUESTION 5
Evolution is the change
a) In acquired characteristics of individuals
b) in the proportion of heritable traits across species
c) in the proportion of heritable traits across generations
d) in the proportion of any trait within populations
e) in the proportion of any trait between populations
Answer (c)
QUESTION 6
Coevolution is a special kind of evolution
a) amongst cooperatively breeding animals
b) in which phenotypes become similar
c) in which phenotypes become less similar
d) In which the trait in one lineage evolves in response to the evolution
of a trait in another lineage and vice versa
e) In which one lineage evolves in response to another but the other
lineage does not evolve.
Answer (d)
QUESTION 7
Convergent evolution is a type of evolution
a) In which closely related lineages evolve similar phenotypes
e. Mollusca Answer (e)
QUESTION 12
The skeletal system in sponges is made up of: a. Rectal pads b. Spicules c. Tagmata d. Biramous limbs e. A and C Answer (b)
QUESTION 13
An exoskeleton is found in the: a. Platyhelminthes b. Gastropoda c. Arthropoda d. Porifera e. B & C Answer (c)
QUESTION 14
Cnidaria are: a. Diploblastic b. Radially symmetrical c. Triplobastic d. A & B e. A & C Answer (d)
QUESTION 15
Tapeworms are members of the Phylum a. Mollusca b. Ctenophora c. Cnidaria d. Platyhelminthes e. Nematoda Answer (d)
QUESTION 16
Pseudocoelomate body plans occur in the: a. Nematoda b. Platyhelminthes c. Annelida
d. Porifera e. A & B Answer (a)
QUESTION 17
Rectal pads are present in the: a. Mollusca b. Arthropoda c. Porifera d. Ctenophora e. Gastropoda Answer (b)
QUESTION 18
Medusae are present in the: a. Choanozoa b. Cnidaria c. Porifera d. Arthropoda e. Mollusca Answer (b)
QUESTION 19
Hydrozoa belong to the phylum: a. Cnidaria b. Gastropoda c. Nudibranchia d. Echinodermata e. None of the above Answer (a)
QUESTION 20
Platyhelminthes are: a. Radially symmetrical b. Bilaterally symmetrical c. Acoelomate d. A and C e. B and C Answer (e)
MODEL ANSWERS
Tony Describe the structure and evolutionary derivation of the angiosperm ovary and outline its functional significance. The angiosperm ovary is constructed of carpels, these being megasporophylls which have fused along their distal margins to enclose the ovules. Where an ovary is composed of multiple carpels, these fuse to each other to produce an ovary with one or more locules. The ovary is distally extended into a style which is terminated by the stigma. The evolution of the ovary is significant from many perspectives: (i) the stigma provides a focal point for the receipt of pollen; (ii) enclosure of the ovules ensures that both the ovules and the fertilization process are protection from herbivores and desiccation; and (iii) following fertilization, the ovary wall develops into a fruit which assists in seed dispersal. Cecile How are nematodes, oligochaetes and echinoderms able to move considering the morphological differences between them? All have hydrostatic skeletons - Nematodes: Relatively rigid cuticle works with the muscles to create a hydroskeleton as nematodes lack circumferential muscles. Their thrashing motion is due to contraction of longitudinal muscles. Oligochaetes: Well-developed, segmentally arranged muscles used for crawling and swimming movements. Short external bristles called setae , or chaetae, composed of chitin. Setae are used to grip the soil , to hold the animal in a tube , or to increase the surface areas of appendages for swimming Echinoderms: Have a water vascular system. Radially organised Ring canal – encircles the animals esophagus Radial canal extends into each arm Water enters through the madreporite flows into the ring canal through the stone canal (reinforced with calcium carbonate) Each radial canal extends through short side branches into the hollow tube feet At the base of each foot is a muscular sac – the ampulla When the ampulla contracts, the fluid prevented from entering the radial canal by a one way valve is forced into the tube foot, extending it. Contraction of longitudinal muscles on the one side of the tube foot causes it to bend Relaxation of ampulla muscles and contraction of all the longitudinal muscles forces water back into the ampulla. 2. Compare the feeding mechanisms of sponges and cnidarians? Sponges lack true tissues Filter feeders – extremely fine food particles
Body consists of two layers of cells separated by a gelatinous region call the mesohyl. Lining of internal cavity contains (spongocoel) 1) choanocytes (collar cells) These cells engulf bacteria and food particles by phagocytosis Water is drawn through the pores into a central cavity: Spongocoel Flows out of the sponge through a larger opening: Osculum Food particles removed by choanocytes Engested by phagocytosis Cnidarians capture food using nematocyst stinging cells Unique to the Cnidaria Very complex structures (compared to the rest of the animal) The cell is called a nematocyte (or cnidocyte) The stinging apparatus is called the nematocyst (or cnidocyst) various types of nematocyst:
- with barbs : penetration & attachment
- hollow : with poison
- sticky : attachment & locomotion
