Lab 1
Porifera & Cnidaria
Chapter 6
Chapter 7
Cayman
Barrel
Sponge
Animal Phylogeny
Animal
Traits
•! Eukaryotic cell
•! Multicellular
•! Heterotrophic
•! Differentiated
tissues
•! Sexual reproduction
Phylum Porifera
Basic sponge body plan
Chapter 7
•! Sponges
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–! Lack tissues
•! Have an inner and outer
lining with amoeboid
cells moving in between
•! Loose aggregation of
cells
–! Sedentary filter feeders
as adults
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•! The body of a sponge
Sponge body types
Phylum Porifera
•! Class Demospongiae: Horny sponges
(ex. bath sponges)
Class Demospongiae
•! Leuconoid body type
•! Skeleton of spongin
fibers +/- silica spicules
•! Class Calcarea: Calcareous sponges
(ex. Scypha, Leucosolenia)
•! Class Hexactinellida: Glass sponges
(ex. Euplectella Venus’s flower basket)
Class Calcarea
http://www.yseisub.it/invertebrati/spongi17.jpg
Class Hexactinellida
•! Syconoid or
leuconoid body type
•! Skeleton of silica
spicules (6-rayed)
•! All 3 body plans
•! Skeleton of
calcium
carbonate
spicules
http://www-biol.paisley.ac.uk/biomedia/graphics/
jpegs/bdcd152.jpg
http://www.businesslink.ch/bilder/red_mpg-euplectella.jpg
Phylum Cnidaria
Body plans of Cnidaria
Chapter 8
•! Radial symmetry
•! Two tissue layers
(Epidermis &
Gastrodermis)
•! Tentacles
•! Specialized stinging
cells (nematocysts)
•! Two body plans
(Polyp, medusa)
Classes of Cnidaria
Class Hydrozoa: Hydra
•! Class Hydrozoa
–! Hydra, Obelia, Portuguese Man of War
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•! Cnidarians are carnivores that use
tentacles armed with cnidocytes, or
“stinging cells,” to capture prey
Hydranths
•! Hydroid
–! colony of multiple individuals
Gonangia
Coiled
thread
Tentacle
Class Hydrozoa: Obelia
•! Hydranth
–! an individual animal
–! feeding polyp
Capsule
•! Gonangium
“Trigger”
–! an individual animal
–! reproductive polyp
Cnidocyte
Discharge of
thread
•! Stem connecting the
individuals
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Prey
–! Coenosarc – inner portion
–! Perisarc – clear, outer portion
Nematocyst – barbed filament with paralyzing toxin
Life cycle of obelia
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Hydranths
Portuguese Man of War
Class Hydrozoa
•! Wind blown Colony.
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Gonangia
•! Medusa and Polyp types
integrated to act as one
individual.
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•! As many as 1000 zooids
(feeding polyps) per colony.
•! Nematocysts secrete powerful
neurotoxin.
Portuguese Man of War
Portuguese Man of War
Class Hydrozoa
Class Hydrozoa
•! One individual modified into
gas sac (pneumatophore).
•! Tentacles (dactylozooids)
armed with stinging cells
•! Prey digested (gastrozooids)
•! Nutrients shared
•! Swimming larva produces a
new colony (asexual –
budding)
•! Specialized individuals in new
colony produce egg and sperm
(gonozooids)
•! Leads to more larval forms.
Class Scyphozoa
Classes of Cnidaria
•! Class Scyphozoa
•! Aurelia life cycle:
- Jellyfish
Medusa
Ephyra
Strobila
Scyphistoma
Planula larva
Classes of Cnidaria
•! Class Anthozoa
–! Sea Anemones, Corals
Class Anthozoa
•! Sea Anemones
–! Polyp stage is
enlarged
–! No medusa stage
•! Corals
–! Colonial
Class Anthozoa
Corals
- reef builders
To focus your microscope, you will always start at the 4X
objective, then proceed with the following steps to focus in
the 10X and high dry 40X.
1. Place the slide on the stage of the microscope with the specimen facing
up.
2. Turn on the illumination and position the specimen over the slot in the
stage.
3. Find the specimen with the 4X objective and bring it into focus using the
coarse adjustment.
4. Use the fine adjustment to focus the specimen in detail
5. Using the revolving nosepiece (not the objective itself) switch to the
10X objective.
6. Use the FINE ADJUSTMENT knob ONLY to bring specimen into focus.
Coarse focusing is not necessary because the microscope is parfocal.
7. Follow steps 5 and 6 with the 40X objective.
We will not be using the 100X Oil Immersion objective
Don’t forget to look
at the side
benches.
There is more to see!
Next week Flatworms &
Roundworms