Objectives
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Mollusc lab
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BIO2135 Animal form and function
Université d’Ottawa / University of Ottawa
BIO2135 Animal form and function
1
15:32
Mollusca
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To dissect and examine the major organ systems of
a clam and squid.
Understand the meaning of adaptive radiation and
why molluscs are a good example of this.
Understand how the ancestral molluscan characters
have been modified in an active predator and in a
sessile filter feeder.
Trace the path of water through the mantle cavity.
Compare the circulatory, digestive, respiratory,
nervous and reproductive systems in the clam and
the squid. Determine how they have been modified
to suit either an active predatory or sessile lifestyle.
Université d’Ottawa / University of Ottawa
2
15:32
Clam dissection
Freshwater clam
– Preserved specimens
for dissection, slides of
glochidia.
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Squid
Umbo
Posterior
– Preserved specimens
for dissection
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Slides
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Mollusc diversity
– Radula and glochidia
Anterior
Position of the adductor
muscles
– Preserved specimens of
chitons and snails
BIO2135 Animal form and function
Université d’Ottawa / University of Ottawa
BIO2135 Animal form and function
3
15:32
Clam dissection
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4
15:32
Squid dissection
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Float your dissection in water or remove
from shell and float
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BIO2135 Animal form and function
Université d’Ottawa / University of Ottawa
Université d’Ottawa / University of Ottawa
Cut open mantle on funnel side
Observe before removing liver and in females
nidamental glands
BIO2135 Animal form and function
5
15:32
Université d’Ottawa / University of Ottawa
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15:32
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How is water moved in, through and out of the mantle
cavity?
How does blood flow through the circulatory system of your
specimen?
What do the ctenidia do?
How is the mollusc shell modified in your specimen and
what function does it have?
How does your specimen move?
How is food captured by your specimen and is it
manipulated in any special way before being swallowed?
Where is the digestive gland and what does it do?
What does the stomach do?
Where is the head and foot in your specimen?
What strategy does your specimen use to defend itself
against other predators?
How is the organization of the nervous and sensory system
adapted to the life style of your specimen? (You may not
however be able to show it.)
How are gametes produced and passed from male to
female?
Which of the two specimens is the most derived mollusc,
why?
Adaptive radiation
What has happened to these original molluscan characters?
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Mantle cavity and
shell shape
Ctenidia/
Circulatory system
Radula
Cephalization/
Nervous system
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Dorsal visceral
mass
Muscular foot and
locomotion
Symmetry
Orientation
Role of cilia
BIO2125
BIO2135 Animal form and function
Université d’Ottawa / University of Ottawa
8
15:32
Timeline
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Prelab talk – 15 min
Clam and squid dissection – 90 min
Discussion - adaptive radiation – 30 min
Retake Obelia pictures?
Next lab
– Annelids requires dissection tools
– Hand in Biological drawing for early bonus (February 29,
2016 before 4:00 PM)
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Remember to complete your online lab quiz for
Mollusca, check your dates!)
BIO2135 Animal form and function
Université d’Ottawa / University of Ottawa
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15:32
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