LAB 6: DIVERSITY—INVERTEBRATE ANIMALS
PURPOSE: Learn the special qualities that characterize four groups: focusing on major
differences between groups and structural similarities within groups.
Goals for all specimens viewed today:
* Be able to identify any specimen by name, phylum, kingdom.
* Characterize each phylum by anatomical features for classification (Table 27.1)
* For each specimen define specific features of anatomy, life cycle and habit.
p. 377-381 Kingdom Animalia: Introduction and classification
__p 337 and Table 379 Understand four of the criteria that organize animals into different
groups: 1) level of organization, 2) symmetry, 3) body plan, 4)coelom (pronounced “SEE-lum”).
__p. 381 Illustrates classification of the entire animal kingdom…
SKIP PHYLUM PORIFERA (SPONGES)
p. 384-387 Section 27.3 Phylum Cnidaria
__ life cycle key terms: medusa, polyp, tentacle, mouth, budding, foot (bottom of polyp form),
egg and sperm.
__ anatomy key terms: organization, symmetry, body plan, nerve net, stinging cells.
__ view Cnidarian diversity
__ sample living Hydra sp. in watchglass, including plenty of water (do not make slide of Hydra)
__ feed Daphnia sp (a small crustacean—another example of a crustacean is a crab) to the Hydra
__ demonstration slide of hydra cross-section (compare to Fig. 27.5) Note gastrovascular cavity
and epidermis.
SKIP OBELIA
How do hydra and jellyfish move around, eat, reproduce?
p. 388-391 Section 27.4 Phylum Platyhelminthes (flatworms)
__ anatomy key terms: organization, symmetry, body plan, ladder-like nerves, cephalization
(did Cnidarians display cephalization?).
SKIP DIVERSITY OF FLATWORMS
__ sample living Planaria sp. in watchglass, cover bottom with water. Observe behavior.
Identify and know function: eyespots, auricle. (see also Figure 27.7)
__ feed egg yolk to Planaria. Observe behavior. Can you see pharynx extending?
__ demo slide of Planaria sp. cross-section: gastrovascular cavity, pharynx (internal view).
__ Table 27.5
SKIP PHYLUM NEMOTODA (ROUNDWORMS)
__ Table page 393: Cnidaria and Platyhelminthes only.
How does planaria move around, eat, reproduce?
Good review: p. 394 #1,4-9, 12-14, 18, 19.
*note: above 2 groups are acoelomate. Following 2 groups are coelomate**
p. 395 Introduction to coelomate animals
p. 396-402 Section 28.1 Phylum Mollusca (mollusks)
__ view Molluscan diversity, basic anatomy
__ select a clam and take it to your desk
*do not cut and handle very gently: return to bucket when finished*
__Read all instructions 1-15, but DO NOT CUT.
Identify structures and know function: hinge, muscles, foot (stiff wedge that can stick out of
shell), mantle, intestine/pericardial sac, incurrent/excurrent siphons, gills, labial palps. We will
not open the visceral mass to view internal organs such as the stomach. Observe location of
mouth (associated with labial palps) and anus (associated with excurrent siphon).
Is this animal bilaterally symmetrical (dividable into 2 identical halves with one cut in one place)
or radially symmetrical (dividable into identical pie shaped wedges)?
__ view anatomy of squid (demo at bench)
Identify structures and know function: tentacle, siphon, gill, heart, stomach, mantle. On diagram,
note location of anus and mouth: what structures are each associated with? How is this similar
to clam?
__ Table 28.2
SKIP PHYLUM ANNELIDA (SEGMENTED WORMS)
How do clams move, eat, reproduce?
How do squid move, eat, reproduce?
What structures do clam and squid have in common?
p. 409-413 Section 28.3 Phylum Arthropoda
__ view diversity of arthropods
__ dissect Your Very Own Crayfish at your desk. *dispose of bits/pieces in animal waste bin*
Identify structures and know functions (see demonstration first): Exoskeleton, head, eye, thorax,
abdomen, antennae, excretory pore of green gland, mouth, walking legs (including specialized
claw), swimmerets (including those specialized for reproduction), uropods, gills (podobranchia &
arthrobranchia), gonad (testis vs. ovaries), stomach, esophagus, green gland, digestive gland
(essentially a “liver”), brain, gastric mill. Be able to tell a male from a female externally.
__Observe live crayfish behavior, Gently use tongs to nudge crayfish: note fleeing, hiding,
aggressive (claw-waving) behavior. Watch activity of antennae, claws, walking legs,
swimmerets, uropods: what is each appendage used for?
SKIP ANATOMY OF GRASSHOPPER
__ Table 28.6: crayfish only
How do crayfish move, eat, reproduce? How does it use anatomy to express behavior?
Good review: p. 418 #1-8, 12