1. Explain the basis for separating the sponges
into the three classes, Calcarea, Hexactinellida and Demospongiae, and state
the composition of the supporting structures in the members of each class.
2. Describe the tissues, organs, nerves, coordination,
digestive system and general activity of sponges to support the statement
that sponges are metazoa of the cellular grade of construction.
3. Describe the forms and functions of the
following sponge cell types, and list any synonyms of these terms: choanocyte,
pinacocyte, porocyte, myocyte, scleroblast, archaeocyte.
4. Define sessile and describe how this term
applies to the phylums porifera and cnidaria.
5. List the primary building materials used
by sponges.
6. Diagram various forms of spicules used
by sponges to construct their skeleton.
7. Trace the pathway of a food molecule through
a common sponge.
8. Detail the three canal systems used by
sponges. Highlight specifically the increase in surface area enabling sponges
to attain larger sizes.
9. Discuss reproductive strategies of the
sponges. Highlight the use of gemmules by freshwater sponges. Also discuss
the lack of differentiation among the sponges allowing them great powers
of regeneration.
10. Explain why coelenterates (cnidarians)
are referred to as animals of the tissue grade of construction.
11. Explain the following terms: planula,
gastrovascular cavity, polyp, medusa.
12. Discuss the basis for the phylum name
cnidaria.
13. Define polymorphism and its applications
to the cnidarian phylum.
14. Describe the three tissue layers and detail
the types of cells found in each.
15. List the classes of cnidarians and give
representatives of each class.
16. Describe the importance of the polyp and
medusa stages in the life cycles of typical Hydrozoa, Scyphozoa and Anthozoa.
17. Describe the appearance of an Obelia
colony, and outline the life cycle, naming each stage.
18. Describe the general form and activities
of Hydra.
19. Explain in detail the origin and functioning
of the nematocyst.
20. Compare the methods of digesting food
in Hydra and Scypha.
21. Compare the nervous systems of Hydra
and Scypha.
22. Compare the gas exchange and excretory
systems of Hydra and Scypha.
23. Describe structure and function of rhopalium,
statocysts and ocillus.
24. Describe the creation of coral reefs by
the anthozoans.
25. Describe three types of reefs.
26. Discuss how coral reefs are currently
being used as barometers of worldwide ecological degradation.
27. Explain the etymology of Ctenophora, and
list the common names and describe the appearance of members of this phylum.
28. Describe the habitat and general importance
of ctenophores.
29. Compare the general appearance and body
construction of cnidarians and ctenophores.
Resources: Text: Animal Diversity, Chapters
6, 7
Internet Resources:
Porifera
http://www.ucmp.berkeley.edu/porifera/porifera.html
http://cas.bellarmine.edu/tietjen/images/phylum_porifera.htm
Cnidaria
http://www.ucmp.berkeley.edu/cnidaria/cnidaria.html
http://orion1.paisley.ac.uk/courses/tatner/biomedia/units/
http://www.mhhe.com/hickmanad4e
Kingdom Animalia
Phylum Porifera- "pore bearers"
5000-10,000 species
seperate branch of metazoa (multicellular)
--> Parazoa "beside animal"
Origins- a) colonial; b) syncytial
Parazoa, multicellular but without
tissues, organs
-uniquely different from other
multicellular groups.
-unusual embryonic development
Larva- free swimming; adult sessile,
plant-like
-cellular level of organization
-diverse, abundant
-all aquatic, mostly marine
-size: tip of finger to 1m across
-radially symmetric or no symmetry at all
-suspension feeders (filter feeders),
no mouth, no gut; Choanocytes,
phagocytosis, intracellular
digestion
-Collagen (spongin), calcium carbonate,
silica for all skeletal components
-no nervous system; reactions slow,
localized and rarely perceptable
-sexual and asexual
**Water canal system unique, central to functioning
of organism evolutionary trends
to increase surface area w/o increaing
volume
CELL TYPES/ BODY PLANS **first group w/ cellular specialization but no tissues
CHOANOCYTES- collar cells pg 115-116
-line inner canals and chambers of sponge
-flagella inside collar creates current
through sponge
-collar serves as filter
-trapped food digested by phagocytic action of main part of cell and archaeocytes
-food also sent to neighboring cells (archaeocytes)
PINACOCYTES- epidermis pg 115
POROCYTES- pg 115, creates openings in
sponge wall, tube like, donut-shaped
MYOCYTES- circle oscula (openings in sponge)
regulate H2O flow
ARCHEOCYTES- pg 116, amoebocytes, form
other cell types as needed; digests
particles from choanocytes.
-sclerocytes- form spicules
-spongocytes- secrete spongin
-collanocytes- secrete collagen
**all cell types found in mesohyl, matrix
of connective fibers and amoebocytes.
Skeleton (system??)
combo of fibers (spongin, collagen)
and SPICULES
-Collagen- most abundant protein in
animal kingdom, found in bone, muscle, hair, nails
-Spicules- composed of silica (2 groups)
or calcium carbonate (one group)
Various forms pg 116
Monoaxon
Triaxon Hexaxon
Respiration/Excretion
-diffusion/ contractile vacuoles
Nutrition
Filter feeding
Intracellular digestion
-phagocytosis by archeocytes
Reproduction
Sexual- egg (ova) & sperm in mesohyl
produce flagellates
larva ---> swim ---> settle --->
grow into sessile adult
MONOECIOUS- male and female in same individual
DIOECIOUS- male and female seperate
Asexual- budding, external growth
gemmules- internal buds, capable of
surviving hostile conditions
fragmentation/regeneration
BODY STRUCTURE
Ostia- openings for water to enter
osculum- opening at top of sponge for water
to exit
Choanocyte-
Spongocoel- inner large cavity
CANAL SYSTEMS pg 113-115
1. Asconoid- simplest (flagellated spongocoel)
-tube shaped -water --->
ostia ---> porocyte
-water expelled through single large
osculum
-Calcarea only (Leucosolenia
)
-group connected by stolon
2. Syconoid- (flagellated canals)
-body folded to produce canals
-greater surface area for exchange
***more surface area ---> more
choanocytes ---> more flagella --->
more water flow ---> more food
---> larger size
-found in Calcarea and Hexactinellida
- Scypha (Grantia)
3. Leuconoid (flagellated canals folded to form chambers much like our lung)
-further increase in S.A. therefore, largest, most efficient
-most common body plan
-colonial w/ individual osculum
-incurrent canals, excurrent canals
-Calcarea, Demospongiae
-bath sponges
CLASSIFICATION 117-119, 120
1. Class Calcarea
-calcium carbonate spicules
-all three body plans
-shallow water
-Grantia
2. Class Hexactinellida
-silica spicules
-all syconoid and leuconoid
-deep H2O
-Euplectella
3. Class Demospongiae
-most common ~80%, bath sponge
-silica spicules, spongin or both
-all leuconoid
-has only freshwater family (Spongilla
)
-cultivated by regeneration
PHYLUM CNIDARIA (COELENTERATA)
-Hydra, jellyfish, anemones, corals; 9-11,000
species
-named for NEMATOCYSTS found in the CNIDOCYTES pg 127-128
-tissue grade construction pg 126-127
*3body layers: epidermis (ecto)
gastrodermis
(endo)
MESOGLEA- connective tissue and amoeboid cells; gelatinous ---> jellyfish
MAJOR ADVANCES pg 123, 124
1. Radial symmetry w/ oral and aboral (tail,
base)
2. mouth and digestive cavity (system)
---> eat large food items
3. Diploblastic and acoelomate?
-often with cells in mesoglea (triploblastic??)
4. POLYMORPHISM pg 124-125- presence
of more than one structural type
of individual
-polyp- hydroid form, sessile (live
single or in colonies)
-medusa- jelly fish form, floating or free swimming
*appear quite different but retain sac like structure w/tentacles around mouth
Polyp - sessile
*relatively thin animals, all
cells close to exposed surface therefore ---> diffusion
prominent
Medusa- mobile
*Bell or umbrella shaped, mouth
down, thick gelatinous mesoglea
Tissue Grade Construction pg 126-128
1. epidermis - one cell thick, 5 cell types
a) epithelio-muscular- contractile,
parallel to axis, longitudinal (muscle-like)
b) CNIDOCYTE- secretes NEMATOCYST
c) sensory- elongated, multipolar, contributes to nerve net
d) interstitial- germ cells, give rise to gametes and epithelial cells
e) mucus secreting cells- muscle fibers, on basal disc.
2. MESOGLEA- variable composition and
thickness, wandering amoebocytes
-w/ or w/o cells; w/ or w/o nerve net
-in jellyfish, rigid, skeletal function
3. gastrodermis- similar to epidermis
but inside
a) nutritive muscle cell, engulf small
food particles, flagellated
b) enzyme gland cell, secrete enzymes
for digestion
NEMATOCYSTS
-anchorage, defense and prey capture
-basis of taxonomy for some groups
-made only by Cnidaria; some predators
able to use nematocysts
Nematocyst types
volvent- entangles
penetrant- penetrates prey, injects
toxin
glutinant- sticky, anchorage
Discharge- chemical or mechanical discharge;
Hydrostatic pressure within
nematocyst
capsule everts tube (inside out) ---> nematocyst explodes and unwinds
-can only be used once
LOCOMOTION pg 125
medusa- jet propulsion- contraction of
ring of circular muscles(?) around bell
polyp- basal creeping, swimming (escape),
sommersaulting (hydra)
NUTRITION pg 126
-all carnivores
-nematocysts, tentacles
-swallow---> cilia, mucus, muscular
action
-extracellular digestion in gastrovascular
cavity
-undigested materials "spit out"
NERVOUS SYSTEM pg 128
-nerve net just below epithelium
-no polarization, fibers conduct in either
direction
Classification 128-140 (summary 140)
CLASS HYDROZOA- hydras and hydroids
(Obelia)
-includes all freshwater cnidaria
-life cycle varies:
1. alternation of polyp and meduse
( Obelia)
2. polyp only (Hydra), budding,
sexual w/ egg and sperm
3. medusa only
*1 and 3 use a planula larva stage
-mesoglea never cellular
-gastrodermis lacks nematocysts
Hydrozoan colony Polymorphism-
Physalia
-highly specialized, pelagic, polyp
and medusa together
CLASS SCYPHOZOA- true jelly fish (
Aurelia)
-large, medusa dominant
-oral arms aid in food capture
-thick gelatinous mesoglea w/ amoebocytes
-predators and ciliary mucus feeders
-gut divided into 4 pouches (increases
surface area!)
-specialized sense organ RHOPALIUM; club
shaped structure around bell
margin w/ STATOCYSTS for balance or
an OCILLUS for light detect.
-tentacles w/ large batteries of nematocysts
CLASS ANTHOZOA (flower animals), anemonies
and corals
-entirely marine
-biradial symmetry
-solitary or colonial
-gut compartmentalized w/ SEPTA (septa
contain gonad and nematocysts)
-mesoglea w/ amoebocytes
-mouth ---> SIPHONOGLYPH- ciliated groove,
water circulation
-tentacles hollow
-mostly carnivorous w/ some ciliary mucus
feeders
-nerve net
CORAL REEFS
-corals, hard and soft, anthozoans, gorgonians,
hydrozoa; algae, especially
coralline algae help cement reefs together
-tropics, usually shallow water, although
up to 300 feet near Jamaica
3 reef types pg 139-140
1. fringing reef- all coral reefs in Hawaii
2. barrier reef: Caroline Islands; Australia
(1/2 to 1 1/2 mile offshore
3. Atolls- rings of coral reef w/ island
above water on reef, lagoon
Phylum Ctenophora - Comb Jellies pg. 140-141