Download 1. Grantia

Spongia (Porifera)
 Immobile,
most are marine, a few freshwater.
 No
obvious tissues and organs divisions.
 No
mouth and digestive tract, there is a spongcoel inside.
 Named
Porifera as well – ostium, osculum.
 Suspension
feeders: choanocytes.
 Mesohyl,
amoebocytes: digesting, transport nutrients to
other cells, and produce materials for skeletal fibers.
 Inner
skeleton is one of the factor for classification:
spicules or spongin fiber.
 Strong
ability of regeneration.
Anatomy of a Sponge
Azure vase sponge
(Callyspongia
plicifera)
Feeding of Choanocytes
Food particles
Flagellum in mucus 襟細胞
Choanocyte
襟細胞
Collar
出水孔 Choanocyte
Osculum
海綿腔
Spongocoel
入水孔
Pore
骨針
表皮層
Epidermis
Water
flow
中膠層
Mesohyl
Phagocytosis of
food particles
Amoebocyte
Spicules
變形細胞
Amoebocytes
變形細胞
Observations
Slides：
1. Grantia spicules (p.136)
Specimens：
1. Grantia – stereomicroscope, spicules (p.136)
2. Spongillidae – stereomicroscope, spongin (p.136)
3. Euplectella (Venus’ Flower Basket ) – Skeletonspicules
(p.136)
Slide: Grantia spicules
p. 136
• In the mesohyl, it is the secretions from Amoebocyte.
• Many kinds of spicules.
Observations
Specimens：
1. Grantia – stereomicroscope, spicules (p.136)
2. Spongillidae – stereomicroscope, spongin (p.136)
3. Euplectella (Venus’ Flower Basket ) – Skeletonspicules
(p.136)
Specimen：The Skeleton of Euplectella aspergillum
(Venus’ Flower Basket)
 has a skeleton that is made from a glass-like
substance and is also as fragile as glass, thus its name
“Glass Sponge.”
(p.136)
The Skeleton of Euplectella
Euplectella aspergillum
Cnidarians
p.137

Gastrovascular cavity, a single opening to this cavity
functions as both mouth and anus.
 There are tentacles arranged in a ring around their mouth,
and has cnidocytes have nematocyst inside. Can protect and
capture prey.
Prey 被補食者
Tentacle
觸手
“Trigger”
Thread
discharges
Cnidocyte
刺絲胞
發射出刺絲
Thread(coiled)
 There are two variations on the body plan: the sessile
polyp and motile medusa.
水螅體型
水母體型
口/肛門
胃水管腔
胃皮層
中膠層
表皮層
口/肛門
Polyp
- asexual reproduction: budding
- sexual reproduction: egg, sperm
Medusa
- sexual reproduction: egg, sperm
Cnidaria
 Class Hydrozoa: Usually has two stages on
the body plan (polyp and medusa), such as
Obelia. Hydras is the one of freshwater
species, and only has polyp stage.
 Class Scyphozoa: In the life cycle, the
medusa generation is obviously and
dominate; the polyp generation is small and
degenerate, such as Aurelia aurita.
 Class Cubozoa: For example: sea wasp
 Class Anthoxoa: Only has Hydras, such as
Actinia and Coral.
Observations
Slides：
1. The asexual budding of Hydra
2. The hydroid colony of Obelia
Specimens：
1. Physalia(p.137~138)
2. Jellyfish
3. Sea anemone
4. Coral
5. Obelia
6. Hydra – stereomicroscope,
Plan, Budding, Ovaries, Spermaries
水螅 (Hydra)
 Hydra reproduce in two ways: asexually and sexually.
Slide: The asexual budding of Hydra
觸手(Tentacles)
芽體(Bud)
 畫圖記錄
藪枝螅 (Obelia)
 Oblia have both the polyp and medusa stages in their life cycle.
營養水螅體
Feeding
polyp
水母體
生殖水螅體
Medusa
Reproductive
polyp
Medusa
bud
MEIOSIS
水母芽
Gonad
生殖腺
ASEXUAL
REPRODUCTION
(BUDDING)
無性生殖
1 mm
Portion of
a colony
of polyps
Key
Haploid (n)
Diploid (2n)
Developing
polyp
Egg
SEXUAL
REPRODUCTION
Sperm
有性生殖
FERTILIZATION
浮浪幼蟲
Zygote
受精卵
Planula
(larva)
Mature
polyp
Slide: Obelia hydroid colony
水母芽
(Medusa buds)
觸手(Tentacles)
生殖水螅體
(Reproductive Polyp)
 畫圖記錄
營養水螅體
(Feeding polyp)
圍鞘
(perisarc)
Observations
Specimens：
1. Physalia(p.137~138)
2. Jellyfish
3. Sea anemone
4. Coral
5. Obelia
6. Hydra – stereomicroscope,
Plan, Budding, Ovaries, Spermaries
Specimen: Physalia
p.138
 Portuguese man-of-war
 It is a colonial hydrozoan that is composed of several types of
modified polyps and medusae.
浮體
(gas-filled bladder)
觸手
(Tentacles)
The tentacles contain several types
of modified polyps and medusae.
Report
• Draw and describe :
1. Grantia spicules
2. Hydra with bud
3. Obelia hydroid colony
• Question
1. Compare the mechanisms of food digestion in
Sponges and Cnidarians.