Phylum Porifora
&
Phylum Cnidaria
Chapter 9 Notes
Phylum Porifora
• Sponges - porifora =
“bears pores”
• Habitat: Mostly Marine
• Sessile (cannot move)
• Sexual or Asexual
– Monoecious – both sexes
in the same individual
– Asexual gemmules –
released when parent
dies in winter
– Asexual regeneration
• Filter feeders – Eat particles
Phylum Porifora
• Loosely organized cells No tissues or organs
• Evolutionarily, most
primitive animals
• ~9,000 species
• Size from <1cm - 2m
• Asymmetrical/
superficially radially
symmetrical
• Central cavity &
branching chambers
– Used to circulate water
Phylum Porifera
• 3 Types of Cells
– Pinacocytes “pea-knock-o-cytes”
• Thin, flat cells
• Line outer surface of sponge
• Porocytes – regulate water circulation
– Mesenchyme cells
•
•
•
•
•
“Amoeboid cells”
Middle, jellylike layer
Reproductive cells
Secrete skeletal elements
Transport and store food
– Choanocytes “funnel - cell”
•
•
•
•
Inner layer
“collar cells” – ring of cells with microvilli surrounding a flagellum
Flagellated
Creates water currents through the sponge
Phylum Porifora
• Sponges skeleton
– Spicules - Microscopic needlelike spikes
– Spongin – fibrous protein made of collagen
Important Groups of Porifora
• Calcarious Sponges
– Spicules made of calcium carbonate
– Spicules are needle shaped
– All marine
• Glass Sponges
– Spicules made of silica
• Bath Sponges
– Colorful sponges
– Siliceous spicules or spongin or both
– 1 family of freshwater sponges
Phylum Cnidaria
Phylum Cnidaria
Number of Species
• 9,000+ Species
Habitat
• All aquatic
• Mostly Marine
Food Source
• Small crustaceans & fish
Phylum Cnidaria
Unique Characteristics:
• Important in coral reef
ecosystems
• Have specialized cells
‘cnidocytes’
– Epidermal/gastrodermal cells
– Used in defense, feeding, and
attachment
• Produce cnidae – a fluid-filled,
intracellular capsule enclosing a
coiled, hollow tube
– Ex: Nematocysts (a type of cnidae)
– Contain barbs to penetrate prey
Phylum Cnidaria
Important groups:
• Jellyfish
• Anemones
• Corals
Phylum Cnidaria
Body Structure
• Radial or biradial symmetry (oral/aboral)
• Have tissues! (…and I don’t mean kleenex…)
• Diploblastic (endoderm + ectoderm +mesoglea)
• Specialized cells –
–
–
–
–
Food gathering
Defense
Digestion
Absorption
• Medusa (dioecious & free swimming) or polyp (sessile &
asexual)
Skeletal Support
• Hydrostatic skeleton – water-filled gastrovascular cavity
Phylum Cnidaria
Digestion/Food Capture:
• Nematocysts – entangle and paralyze prey
• Tentacles contract to bring food to the mouth
• Enzymes and lysosomes break down the food
in gastrovascular cavity
• Makes a sort of soupy mixture
• Phagocytosis
Phylum Cnidaria
Muscular Movement:
• Pulsate muscles to move tentacles in an
inchworm fashion and glide
• Nutritive muscular cells move materials in and
out of the gastrovascular cavity
Nervous Communication:
• Primitive nerve net – does not lead to
anything
Excretory Waste Removal &
Respiration
• Both processes occur in the gastrovascular
cavity
• Cnidarians have a large surface-area-tovolume ratio
– All cells are near body surface
– O2, CO2, and nitrogenous wastes exchange by
diffusion
Reproduction
• Mostly dioecious
• Sperm & egg released from gastrovacular cavity
– Planula = ciliated, free-swimming larva  forms
polyp
– Polyps reproduce by budding  forms medusa
• Alternation of generations life cycle