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BIOL 2030 Study Guide - Calcareous Sponge, Spongin, Siphonophorae


Department
Biology
Course Code
BIOL 2030
Professor
German Reyes

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1
Lab 2 Phylum Porifera and phylum Cnidaria
Phylum Porifera
Adults sessile and attached
Radial symmetry or asymmetrical
Multi-cellular ; loose aggregation of cells
Skeleton made of collagen and spicules (calcareous or siliceous)
No organs or true tissue
Specialized for filter-feeding
Digestion is intracellular (no mouth , anus or digestive system)
Excretion and respiration by diffusion
No nervous system
Asexual (budding or formation of gem mules)
Sexual (eggs and sperm produce ciliated larvae)
Dioecious
Mostly marine; few are freshwater
Grantia
Kingdom :- Animalia
Phylum:- Porifera
Class:- Calcarea
Order:- Leucosolenida
Genus:- Grantia
Tubular or syconoid-shaped
Water enters via small pores (incurrent pores)and exists via large pore (osculum)
Outer surface covered in flat cells (pinacocytes),inner choanocyte layer and the
middle is mesohyl (gelatinous protein matrix)
Pinacocoytes at base of sponge secrete a substance that attached sponge to its
substrate
Water flow;incurrent pores> incurrent canals >radial canal (flagellated
choanocytes)>central cavity/spongocoel > osculum
Choanocytes generate feeding current
Skeletal components (non-living)-spongin fibers,spicules of calcium
carbonate/silicon dioxide.

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Phylum Cnidaria
Sedentary or free-swimming metazoan
Radial symmetry
Body wall composed of two cell layers;
o Outer ectoderm
o Inner endoderm
o Structure-less layer between them(mesoglea)- contains cells derived from primary cells
Nervous system is a network of cells
No specialized organs for excretion(its by diffusion)
Asexual (budding)
Sexual (planula larva- ovoidal and uniformlyciliated is produced)
2 body forms (polyp or medusa)
Nematocysts (stinging threads)- for capturing prey
Class Hydrozoa :-Polyp and medusoid body forms occur in successive stages of life cycle
-polyps(colonies) have 2 types ;gastrozooids(feeding) and gonozooids
(asexual reproduction)
- Medusoid reproduces sexually to produce a planula larva

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Order Hydroida : well developed polyploidy generation.(solitary or colonial).
Usually buds off as free medusa. Eg. Hydra (solitary with no medusoid stage ),
Velella and Porpita(free-floating polymorphic colonies), Obelia
Order Siphonophora:- swimming colonies. Consisting of many kinds of polyp
and medusae (polymorphic).medusae attached to stem. marine. Eg. Physalia
(Portuguese man of war).
Class Scyphozoa :- Medusoid stage as main stage of life-cycle
-polypoid form only in larva.
-Eg. Aurelia (common jelly-fish)
Class Anthozoa:- corals, sea anemones
- attached polyps
- NO medusa
- Some members posses a skeleton
-gonads found in septa
- all marine
- Soliatry or colonial
-Eg. Gorgonia (sea fan), Pennatual (feather-like sea pen), Metridium (sea
anemone with no skeleton), Meandria (brain coral with big external calcareous
skeleton)
Hydra
Kingdom :- animalia
Phylum:- Cnidaria
Class:- Hydrozoa
Order:- Hydroida- Anthomedusa
Genus:- Pelmatohydra (brown hydra)
Batteries of intact nematocytes are located in cnidocyte
Epidermis of hydra possesses epitheliomuscle cells and interstitial cells
Gastrodermis possesses flagellated nutritive muscle cell and gland cells
Food vacuoles are present in gastrodermal cells
Space in the centre of the cross section is the gastrovascular cavity (enteron)
Mesoglea thin layer between epidermis and gastrodermis
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