Biology Inquiry
with Invertebrates
Charlie Drewes
Ecology, Evolution &
Organismal Biology
Iowa State University
Ames, IA 50011
“ I hear and I forget,
I see and I remember,
I do and I understand.”
Confucius
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Guided inquiry
“BIOLOGY in ACTION”
►
Open-ended inquiry
”Stuck-on Artemia”
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Independent Inquiry
“Biological Smoke Detectors”
‘BIOLOGY in ACTION’
31 Interactive &
Computational
Animations
WEB-based and CD
(non-proprietary)
INTERDISCIPLINARY AREAS:
Biology, Math, Physics
TOPICS & FOCAL POINTS:
Locomotion
Biomechanics
Cell Biology
Animal Behavior
Physiology
Development
Invertebrate Biology
CURRICULAR UTILITY:
 adjuncts to hands-on laboratory
inquiries with living organisms
 adjuncts to lecture / discussion
(homework or student presentations)
 focal points for problem-based
learning (computation & data analysis)
RED = interactive animations with computations and control features
BLACK = GIF animations with questions and links
►
►
►
LINK to CONTENTS
Lumbriculus variegatus
California blackworm
Annelida (Oligochaetea)
Hands-on Lab Investigations
with Living Lumbriculus
 Segment Regeneration (ABLE)
(development; asexual reproduction)
 Circulatory Function (ABT)
(blood flow, pulse rate)
 Locomotion & Movement (ABT)
(swimming, crawling, reversal behavior)
Animations of Lumbriculus blood vessel pulsations:
Adjunct to lab inquiry of circulation in living worms
Interactive format
Circulatory
Computations
 pulse frequency
(pulse waves /sec)
 pulse velocity
(mm /sec)
 blood volume
(cc3 / time)
0 sec
1 sec
2 sec
3 sec
4 sec
5 sec

Animation of helical
swimming in Lumbriculus:
A follow-up to student
lab inquiry of locomotion
in living worms
T
A
I
L
T
O
U
C
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Helical swimming
in Lumbriculus:
A unique form of
animal locomotion
elapsed time (f1f7)
= 0.2 sec
 direction of
wave & backthrust
forward velocity = ?
wave frequency = ?
wave velocity = ?
Reynolds number = ?
 direction
of swimming
The Formation of Vegetable
Mould, through the Action
of Worms,
with Observations on Their Habits
by
Charles Darwin
1881
Animation of peristaltic crawling…
…a follow-up to student lab inquiry about
hydrostatic skeletons & locomotion
without appendages in living invertebrates
(e.g., terrestrial and aquatic annelid worms)
circular
muscle
wave

CM 
CM 
CM 
longitudinal
muscle
wave
 LM
 LM

 LM
ELONGATED SEGMENT:
length = 17.5 mm; diameter = 13 mm
volume = π · r2 · length = 2,321 mm3
I
I
SHORTENED SEGMENT:
length = 7.5 mm; diameter = 20 mm
volume = π · r2 · length = 2,355 mm3
Open-ended inquiry with living crustaceans
Artemia franciscana
North American brine shrimp
Artemia
fertilized
eggs in
brood sac
X
life
cycle
winter
‘eggs’
Adult
female
HATCH
transparency
strip with grid
10 mm x 10 mm
strip of
double-stick
tape covers grid
plastic petri dish
tape holds
strip to dish
“Paint” cysts
onto tape with
small, soft, dry
paintbrush
STUCK-on ARTEMIA
Technical Advantages
 easy handling & transfer of cysts
 uses small, quantifiable number of cysts
 follow development of individual cysts
 cysts stay in single focal plane
 use dissecting or compound microscope
 manipulation of many relevant variables
Hatching of encysted
Artemia embryos
Encysted late
gastrula stage
Cyst hydrates
and swells
Cyst wall splits
Membrane-bound
“umbrella” stage
Nauplius larva
emergence
Each day, a pipet is used to remove and
count hatched, swimming nauplius larvae
100
%
H
A
T
C
H
80
60
40
20
0
day 0
day 1
day 2
day 3
day 4
Experimental variables
PHYSICAL & CHEMICAL ENVIRONMENT
Temperature (heating, cooling, freezing)
Sun light (UV)
Microwave irradiation
Salinity (hypo- & hyperosmotic)
Repeated hydration
Dissolved oxygen
Toxicants (pollutants, pharmacological agents)
Measurements & End-points
Hatching %
Hatching time-course
Developmental anomalies
Larval motility
Molting & growth
Independent inquiry
CONCEPTS & PRACTICAL IDEAS
1)
2)
3)
4)
5)
6)
7)
8)
(non-cookbook)
Invertebrates as toxicity test organisms
Selection of test chemical(s)
Exposure / treatment protocols
End-points (lethal versus sublethal effects)
Concentration range-finding (preliminary expts)
Final testing and analysis
Materials, supplies, resource references
SAFETY ISSUES & GLOSSARY
Invertebrates
are more than…
…creepy, crawly novelties
…taxonomic survey material
…anatomy & dissection material
Use of living
invertebrates for
biology lab inquiries…
… engages & enlivens interest
… makes biology more than
a ‘spectator sport’
… promotes analytical thinking
Take-Home Materials
 CD: “BIOLOGY in ACTION” - 31 animations
& “Freshwater Invertebrates” - PowerPt file
 Copy: Contents & Animation Q/A’s for Instructor
 Copy: Student lab inquiry: “ Stuck-on Artemia”
 Reprint: “Biological Smoke Detectors”