Post on 26-Apr-2019
1
PH. PLATYHELMINTHES
* CLASSES:
1.
2.
3.
4.
1.
2.
3. GVC (Incomplete gut)
4. Dorsoventrally flattened
5. Bilateral symmetry
6.
7.
8. Excretory system ⇒
9. 2 mm ⇒ 10 M, ~20,000 spp., many parasitic
10. Complex reproductive & musculature systems
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PH. PLATYHELMINTHES
* GENERAL BODY FORMS:
* BODY WALL & LOCOMOTION:1. Ciliary gliding2. Muscular undulations
3
PH. PLATYHELMINTHES* FEEDING:
1. PHARYNGES:A. Simple, non-eversible
B. Cylindrical, eversible
C. Ruffled (plicate), eversible
GVC
GVCGVC
GVC
GVC
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PH. PLATYHELMINTHES
* FEEDING:
2. DIGESTION:A. Primary → extracellularB. PhagocytosisC. Final → intracellular
3. GASTROVASCULAR CAVITIES: GVCA. None
B. Simple sac
C. Convoluted
D. Tri-branched
E. Multi-branched
GVC
GVC
5
PH. PLATYHELMINTHES
* EXCRETION & OSMOREGULATION:
1. ProtonephridiaA. Ectodermal origin
B. 2-celled unit
C. Closed internally; open externally
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PH. PLATYHELMINTHES
* NERVOUS SYSTEM:
1. Ladder-like or net-like
2. Cephalization
3. Ectodermal origin
4. INVERTED PIGMENT CUP OCELLUS
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PH. PLATYHELMINTHES
REPRODUCTION:
ASEXUAL:1. Transverse fission
2. Regeneration
SEXUAL:1. Hermaphroditic
2. Mutual cross fertilization
3. Internal fertilization via hypodermic impregnation
ORGAN SYSTEMS (within same animal):
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PH. PLATYHELMINTHES
ONTOGENY:
GVC
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PH. PLATYHELMINTHES
LIFECYCLES:
1. CESTODA:(EXAMPLE: TAENIA)
adult tapeworm [sexual reproduction] human intestines
bladder worms zygotes [via proglottids]
oncosphere larva [living in cow]
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PH. PLATYHELMINTHES
LIFECYCLES:
2. MONOGENEA:(EXAMPLE: ANAPLOCOTYLOIDES & DACTYLOGYRUS)
adult fluke[sexual reproduction]
gills of fish
swimming zygoteslarva
oncomiracidium larva [bottom of pond]
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PH. PLATYHELMINTHES
LIFECYCLES:
3. TREMATODA:(EXAMPLE: OPISTHORCHIS)
adult fluke[sexual reproduction] in human bile ducts
metacercarial cyst
[in fish muscle tissue]zygotes
cercaria larva
[free swimming]miracidium larva
[asexual redia in snail]
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PH. PLATYHELMINTHES
* PHYLOGENETIC CONTEXT & CHARACTER EVOLUTION: