3. WHAT IS FILTER FEEDING?
• FILTER FEEDING IS A PROCESS OF FOOD PROCUREMENT IN
WHICH FOOD PARTICLES OR SMALL ORGANISMS ARE
RANDOMLY STRAINED FROM WATER.
• FILTER FEEDING IS FOUND PRIMARILY AMONG THE SMALL TO
MEDIUM SIZED INVERTEBRATES BUT OCCUR IN A FEW LARGE
VERTEBRATES (EXAMPLE- FLAMINGOS, BALLEN, WHALES.)
• IT IS A MAIN CHARACTERISTIC OF AQUATIC ANIMALS.
4. INTRODUCTION TO UNIO
• PHYLUM:- MOLLUSCA (UNSEGMENTED BILATERALLY
SYMMETRICAL AND PROVIDED WITH VISCERAL MASS FOOT
AND MANTLE).
• CLASS:- PELECYPODA OR BIVALVIA
• ORDER:- UNIONIDA (GILL FILAMENT UNITED BY INTER-FILAMENT
AND INTER-LAMELLAR JUNCTIONS.)
• FAMILY:- UNIONIDAE
• GENUS:- UNIO ( FRESH WATER MUSSEL).
5. HABIT AND HABITAT
• UNIO IS FOUND IN PONDS , LAKES, RIVERS, AND STREAMS.
• THE ANIMAL IS USUALLY BURIED IN THE MUD.
6. GENERAL CHARACTERISTICS OF
UNIO
• COMMONLY CALLED AS FRESH WATER MUSSEL OR CLAM.
• BODY DARK BROWN, UNSEGMENTED, BILATERALLY
SYMMETRICAL AND FLATTENED.
• ANIMAL IS COMPLETELY ENCLOSED IN TWO EQUAL BIVALVE
SHELLS.
• THE BIVALVE SHELL IS HELD TOGETHER BY ANTERIOR AND
POSTERIOR ADDUCTOR MUSCLES AND IT CAN BE OPENED BY
RETRACTOR MUSCLE.
7. 1. JUST BELOW THE TWO VALVES OF THE SHELL THERE ARE
FLAP- LIKE MANTLE LOBES ON EITHER SIDE WHICH PROVIDE
INSULATION BETWEEN THE HARD SHELL AND SOFT BODY.
2. MANTLE IS ALSO RESPIRATORY.
3. GILLS OR CTENIDIA ARE LARGE AND MADE OF TWO GILLS
PLATES ON EITHER SIDE OF BODY UNDER THE MANTLE
FLAPS.
4. THEY ARE RESPIRATORY AS WELL AS FOOD GATHERING IN
FUNCTION.
8.
9. FOOD
• UNIO IS A PLANKTONIC FEEDER.
• ITS FOOD CONSIST OF DIATOMS, PROTOZOA, OTHER
MICROORGANISMS AND ORGANIC DITRITUS BROUGHT IN BY
THE CIRCULATING WATER CURRENT
10. DIGESTIVE SYSTEM
• UNIO IS A FILTER FEEDER AND TRAPS PLANKTONS BY THE
ENLARGED SEIVE-LIKE GILLS PLATES OR DEMIBRANCHS.
• WATER CURRENTS ENTERS THE MANTLE CAVITY THROUGH THE
INHALENT SIPHON AND MOVES UPWARD THROUGH THE GILLS
TO THE SUPRABRANCHIAL CHAMBER.
• GILLS ARE COATED WITH MUCOUS WHICH TRAPS THE
PLANKTONS ON THE GILLS SURFACE.
11. ALIMENTARY CANAL
1. MOUTH:-
• IMMEDIATELY BELOW THE ANTERIOR ADDUCTOR MUSCLES LIES
THE MOUTH WHICH IS A TRANSVERSE SLIT.
• ON EACH SIDE OF THE MOUTH ARE TWO CILIATED TRIANGULAR
FLAPS, THE EXTERNAL AND INTERNAL LABIAL PALPS.
• THE PALPS BEAR CILIA.
2. OESOPHAGUS:-
• A SHORT TUBE , RUNS DORSALLY FROM THE MOUTH TO OPEN
INTO THE STOMACH.
12. 3. STOMACH:-
• A LARGE , OVAL SAC EMBEDDED IN THE DIGESTIVE GLAND.
• THE EPITHELIUM IS THROWN INTO FOLDS.
• TWO NARROW DUCTS FROM THE DIGESTIVE GLAND OPENS IN
THE STOMACH. OCCASIONALLY, A MUCOUS ROD, THE
CRYSTALLINE STYLE WHICH PLAYS AN IMPORTANT ROLE IN
DIGESTION FOUND IN THE STOMACH. IT CONTAINS A DIASTALIC
ENZYME.
4. INTESTINE:-
• THE INTESTINE IS A NARROW TUBE, AND AFTER ITS ORIGIN
FROM THE VENTRAL SURFACE OF THE STOMACH NEAR ITS
POSTERIOR END, DESCENDS INTO THE VISCERAL MASS ABOVE
13. 4. RECTUM:-
• THE RECTUM PIERCES THE PERICARDIUM AND THE VENTRICLE OF THE
HEART, RUNS PARALLEL TO THE DORSAL SURFACE OF THE MUSSEL AND
OPENS INTO THE EXHALENT SIPHON BY THE ANUS.
• THE INTERNAL WALL OF THE RECTUM IS THROWN INTO LONGITUDINAL
FOLDS TO FORM A RIDGE KNOWN AS TYPHOSOLE.
• MOVEMENT OF CILIA ON THE GILL SURFACE PUSHES THE FOOD
PARTICLES DOWNWARD INTO THE FOOD GROOVE PRESENT ON THE
LOWER MARGIN OF GILL LAMINA.
• INSIDE THE FOOD GROOVE THE FOOD IS CONSTANTLY PUSHED
FORWARD TOWARD THE MOUTH WHERE TWO PAIRS OF FEEDING PAPLS
SORT OUT THE SAND PARTICLES FROM THE MUCOUS CORD AND PUSH
THE FOOD AND MUCOUS INTO THE MOUTH.
14.
15. FEEDING
• THE RESPIRATORY WATER CURRENT CREATED BY THE MOVEMENT OF
CILIA ON THE GILLS CARRIES FOOD PARTICLES AND OTHER MATTERS.
• THE HEAVY PARTICLES DROP IN THE MANTLE CAVITY AND ARE EXPELLED
OUT THROUGH EXHALENT SIPHON BY THE MOVEMENT OF CILIA IN THE
MANTLE.
• THE GILL LAMINAE ARE COVERED WITH A THIN SHEET OF MUCOUS AND
FOOD PARTICLES ARE ENTANGLED IN IT.
• THE MOVEMENT OF LATERAL CILIA ON THE GILLS DRIVES MUCOUS SHEET
TO THE VENTRAL EDGE OF THE GILLS BEARING FRONTAL CILIA.
• THE FRONTAL CILIA DRIVES THE MUCOUS STRING FORWARD TO THE
CILIARY TRACT OF THE LABIAL PALPS.
16. • FURTHER ASSORTING TAKES PLACE HERE, THE LARGER
PARTICLES ARE CARRIED TO THE TIPS OF THE LABIAL PALPS ,
DROP OFF IN THE MANTLE CAVITY AND REMOVED TO YHE
EXTERIOR.
• THE STRING WITH THE FOOD MATTERS ARE CARRIED TO THE
DEEP GROOVE, THE FOOD GROOVE BETWEEN THE TWO PAPLS
LEADING TO THE MOUTH AND DRIVEN TO THE OESOPHAGUS
17.
18. CILIARY FEEDING
IN GILL FILAMENT THERE ARE 3 TYPES OF CILIA.
1. FRONTAL CILIA
2. LATERO-FRONTAL CILIA
3. LATERAL CILIA
19. • BY THE MOVEMENT OF LATERAL CILIA WATER CONTAINING FOOD
PARTICLES REACHES TO MANTLE CAVITY.
• LIGHT FOOD PARTICLES REACH TO CTENEDIA.
• CTENIDIA SECRETE MUCOUS ENTANGLED WITH FOOD
PARTICLE(PLANKTONS) AND FORM STRING LIKE MASS.
• FRONTAL CILIA CARRIES FOOD TO MOUTH REGION.
• MOVEMENT OF CILIA OF LABIAL PALPS CARRIES FOOD IN MOUTH
• THEN SELECT FOOD PARTICLES.
• THEN MOUTH TO OESOPHAGUS TO STOMACH THEN INTESTINE AND LAST
RECTUM.
20.
21. DIGESTION
DIGESTION IN UNIO IS OF TWO TYPES –
EXTRACELLULAR – IN STOMACH
INTRACELLULAR – BY DIGESTIVE GLAND
• INTRACELLULAR DIGESTION PLAYS AN IMPORTANT ROLE IN NUTRITION.
• DIGESTIVE GLAND SECRETE ENZYMES THAT IS POURED INTO THE
STOMACH AND THEN THE DIGESTION TAKES PLACE.
• CARBOHYDRATES ARE THE ONLY ENZYMES IN THE STOMACH AND
CARBOHYDRATES DIGESTION TAKES PLACE HERE.
• INTRACELLULAR DIGESTION ALSO TAKES PLACE IN DIGESTIVE GLAND BY
WANDERING AMOEBOCYTES.
