Porifera - PowerPoint PPT Presentation
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Title: Porifera
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Porifera
- With pores, sessile, asymetric, diploblastic
- Cells- outer pinacoderm, middle- amoebocytes and
inner-choanocytes - Skeleton- spicules and spongin fibres
- Water canal system
- Eg Sycon, Spongilla ( Fresh Water sponge),
Euplectella ( Glass sponge)
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Phylum Cnidaria
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- General Characteristics
- They are radially symmetrical oral end
terminates in a mouth surrounded by tentacles. - They have 2 tissue layers
- Outer layer of cells - the epidermis
- Inner gastrodermis, which lines the gut cavity
or gastrovascular cavity (gastrodermis secretes
digestive juices into the gastrovascular cavity) - In between these tissue layers is a noncellular
jelly-like material called mesoglea
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- Cnidarian Body Plans
- Polyp form
- Tubular body, with the mouth directed upward.
- Around the mouth are a whorl of feeding
tentacles. - Only have a small amount of mesoglea
- Sessile
- Medusa form
- Bell-shaped or umbrella shaped body, with the
mouth is directed downward.
- Small tentacles, directed downward.
- Possess a large amount of mesoglea
- Motile, move by weak contractions of body
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- Nutrition
- Cnidarians are carnivores with hydras and corals
consuming plankton and some of the sea anenomes
consuming small fishes - They use they tentacles to capture prey and
direct it toward the mouth so that it can be
digested in the gastrovascular cavity via
secretions from gland cells (extracellular
digestion) some food is phagocytized by special
cells and digestion occurs intracellularly - The gastrovascular cavity exists as 1 opening
for food intake and the elimination of waste - There is no system of internal transport, gas
exchange or excretion all these processes take
place via diffusion
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- Alternation of generation
- Mouth or hypotostome present
- Ctenophora Comb jellies
- diploblastic, tissue level organisation
- An outer epidermis, mesoglea with amoebocytes,
and - An inner gastrodermis
- Colloblasts- on epidermis of tentacles- for prey
capture - locomotion- cilia with comb plates for nutrition
- Eg Ctenoplana Hormephora
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- Platyhelminthes Flat worms
- unsegmented, bilateral symmetry, triploblastic
- Acoelomate, organ system level of organisation
- Suckers and hooks for holding the intestine of
host - Incomplete gun only mouth present, no anus
- Excretion- Flame cells
- Regeneration capacity high in Planarians
- Eg Taenia solium, Fasciola hepatica
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- NEMATHELMINTHES - Round worms / thread worms
- Bilateral symmetry, Triploblastic , pseudo
coelomate - Alimentary canal- complete with muscular pharynx
- No respiratory and circulatory system
- muscles- Circular and longitudinal
- Sex- seperates male shorter than female
- Fertilisation internal
- Ascaris, Wuchereria, Ancylostoma ( Hook worm)
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- Annilida Annullus little ring
- Triploblastic, bilateral symmetry, coelomate
- Metamerism
- Muscles- longitudinal and circular
- Digestion complete
- Excretion- nephridia circulation- closed
- Some are bisexual
- Development- indirect through Trocophore larva
- Eg Pheritima, Tubifex ( blood worm), Neries
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Arthropoda
- Body Head, thorax and abdomen
- Jointed appendages, antennae, eyes ( ommatidia)
and statocysts - Digestive system is complete
- Chitin undergoes Ecdysis/ moulting
- Respiration- Gills/ trachea/ Book lungs/ / Book
Gills - Excretion- Malphigian tubules/ nephridia
- Fertilisation- internal , oviparous
- Apis , Bombyx, Laccifer, Anopheles, culex,
locusts, Limulus
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Mollusca ( soft body)
- Body- Head, Visceral mass , muscular foot
- Radula- rasping organ
- Body wall with mantle- secretes shell
- Digestion complete excretion- nephridia
- Unisexual, external fertilisation, oviparous
- Indirect development- Veliger, trocophore and
Golchidium larvae
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Echinodermata
- Endoskeleton- calcarious plates with spines
- larvae- bilateral sym and adults- radial sym
- Water vascular system with tube feet, radial
canals excretion, circulation - High regeneration capacity
- development- indirect Plateus, bipinnaria and
auricularia
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Hemichordata
- Body- Proboscis, collar and trunk
- proboscis- Ciliated for collecting food
- Mouth- between proboscis and collar
- Stomochord- similar to notochord
- Excretion- proboscis gland
- Reproduction- sexual, dev- indirect ( tornaria)
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Chordata
- Protochordata
- Includes tunicates ( urochordates) and
Cephalochordates - Tunicates- notochord and nerve chord present only
in larva - Cephalochordates- nerve chord and notochord
persistant
- Vertebrata
- Notochord replaced by vertebral column
- Respiration gills/lungs
- Circulation closed
- -Includes Agnatha and Gnathosomata
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