Download Biol 1031 Lab 7 Slides

Lab 7:
Animals I: Porifera, Radiata,
and Introduction to Bilateria
Part A:
Sponges (Phylum Porifera)
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video
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spongin (collagen)
No Symmetry (asmmetrical);
no true tissue
Task A-1: Sponges (Phylum Porifera)
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Slide: Scypha – look for holdfast, osculum
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Slide: sponge spiculues
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body types: simple, intermediate, complex – draw
arrows on Fig. 7-3; look at specimens
Part B:
Phylum Cnidaria
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have true tissues
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radial symmetry
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have stinging cells (cnidocytes) on tentacles and
elsewhere
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tentacles surround mouth
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gastrovascular cavity with extracellular digestion;
one opening serves as both mouth and anus
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after larval stage (planula), polyp and/or medusa
stage(s)
Copyright  2003 Scott A. Bowling
Fig. 44.8
Part B:
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Phylum Cnidaria
three classes
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Hydrozoa – hydroids
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Scyphozoa – jellyfish
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Anthozoa – sea anemones and corals
Task B-1: Phylum Cnidaria
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Hydrozoa – hydroids
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usually have both polyp and medusa stages
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example: Hydra (solitary freshwater organism)
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slides: look for tentacles, bud, cnidocytes,
gastrovascular cavity, mouth, epidermis and
endodermis (gastrodermis) with mesoglea
between
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living specimen – note its movement, look
for external structures
Task B-1: Phylum Cnidaria
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Hydrozoa – hydroids (continued)
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example: Obelia (colonial marine organism)
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slides: note structures from Fig. 7-6 (feeding
polyps, reproductive polyps, medusa buds,
medusae, tentacles, gonads, mouth,
gastrovascular cavity, etc.)
example: Portuguese man-of-war (colonial)
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note both polyps and medusae in a colony
that has superficial resemblance to a large
medusa
Task B-1: Phylum Cnidaria
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Scyphozoa – jellyfish
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dominant medusae; some have no polyp form
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example: preserved specimen – treat it gently!
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note tentacles, oral arms, mouth,
gastrovascular cavity, gonads, thick jelly-like
mesoglea
Task B-1: Phylum Cnidaria
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Anthozoa – sea anemones and corals
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polyp stage only
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sea anemones – very muscular
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some sessile, but not all (…see video)
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example: preserved specimen (treat gently!)
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note mouth, tentacles, pedal disc
Task B-1: Phylum Cnidaria
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Anthozoa – sea anemones and corals (continued)
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corals
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most secrete calcium carbonate exoskeletons
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look at dry coral specimens; note distinct
cups indicating origins from separate polyps
Part C:
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Bilateria
Bilateria – animals with bilateral symmetry
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associated with cephalization (forming a true
head)
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learn dorsal/ventral and anterior/posterior
Fig. 44.3b
Part C:
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Bilateria
different forms based on fluid-filled body cavity
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acoelomate – no body cavity
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pseudocoelomate – body cavity bound by
mesoderm on one side, endoderm on the other
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coelomate (or eucoelomate) – “true” body
cavity, surrounded by mesoderm on both sides
Fig. 44.4
Coelomates
coelom surrounded by mesodermal
tissue (also called eucoelom)

allows for more complex organs,
especially digestive system
Copyright  2003 Scott A. Bowling

Part C:
Bilateria
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body cavities allow many things, such as
hydrostatic skeleton, internal organs, circulatory
system, etc.
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coelom allows for more specialization than
pseudocoelom does
Part C:
Bilateria
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Two major clades
within Bilateria:
Protostomia
(covered in this lab
and lab 8) and
Deuterostomia
(covered in lab 9)
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Within
Protostomia, two
major clades
Part C:
Bilateria
non-molting protostomes (labs 7 and 8)
vs.
molting protostomes (lab 8)
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Two selected non-molting phyla covered in this lab:
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Phylum Platyhelminthes – flatworms
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Phylum Annelida – segmented worms
Part C:
Phylum Platyhelminthes – flatworms
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acoelomate
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dorsoventral flattening in most
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incomplete digestive tract, when present (combo
mouth/anus, just like Cnidarians)
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most are parasitic; some are hunters
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hermaphroditic
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….video
Task C-1: Phylum Platyhelminthes – flatworms
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3 classes
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Turbellaria
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Cestoda – tapeworms
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Trematoda – flukes
examine specimens and
slides, look for structures
noted in Figs. 7-10, 11, and
12 such as ocellus, pharynx,
intestine, scolex, proglottids
Part C: Segmented Worms (Phylum Annelida)
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segmented – linear repetition of body parts;
specialization in some (such as head); often
separated by septa
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use coelom for hydrostatic skeleton
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closed circulatory system
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excretory tubules (metanephridia)
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most have chitinous bristles (setae) on most
segments – for sensing, and locomotion
Task 2: Segmented Worms (Phylum Annelida)
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3 classes
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Polychaeta (polychaetes)
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Oligochaeta (earthworms)
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Hirudinea (leeches)
Task C-2: Segmented Worms (Phylum Annelida)
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annelid box and slide: examine the preserved
specimens and slide, note the following:
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Polychaeta – clamworm:
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distinct head with tentacles, eyes, jaws
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fleshy parapodia on segments – used for
locomotion
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compare to plume worm (not in box – demo
only)
Task C-2: Segmented Worms (Phylum Annelida)
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annelid box and slide:
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Oligochaeta – earthworm:
• rub to feel chitinous setae, used for holding to
soil
• clitellum – band used in mating; is nearer to
the anterior end of the worm
• reproductive pores anterior to clitellum
(earthworms are hermaphroditic)
• cross-section slide: compare to Fig. 7-14, note
structures bolded in you manual such as
coelom
Task C-2: Segmented Worms (Phylum Annelida)
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annelid box:
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Hirudinea – leech:
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dorsoventral flattening
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lack of setae and parapodia
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less distinct segmentation
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suckers for attaching to host for feeding
(leeches are blood-sucking parasites)
TODAY YOU WILL TAKE AN
EXIT QUIZ !!!