Biol 1031 Lab 7 Slides
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Transcript 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 !!!