MARINE INVERTEBRATES: STOP 2 PHYLUM CNIDARIAN - JELLYFISH.
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Transcript of MARINE INVERTEBRATES: STOP 2 PHYLUM CNIDARIAN - JELLYFISH.
MARINE INVERTEBRATES: STOP 2
PHYLUM CNIDARIAN - JELLYFISH
JELLYFISH INTRO
3 CLASSES
• SCYPHOZOA
• COMMON JELLIES
• HYDROZOA
• PORTUGESE MAN-OF-WAR
• OBELIA
• CUBOZOA
• BOX JELLIES
COMMON CHARACTERISTICS
• EVOLVED OVER 600 MILLION YEARS AGO
• CONTAIN CNIDOCYTES – STINGING CELLS• WHICH EXPEL BARB-LIKE
NEMATOCYSTS
• MOST BLIND• EXCEPT BOX JELLIES
• HAVE EYE CLUSTERS
COMMON CHARACTERISTICS
• ALL ARE CARNIVOROUS
• SINGLE-OPENING DIGESTIVE TRACT (2 WAY)
• MOUTH AND ANUS ARE AT SAME OPENING
• ECTOTHERMIC
• NO BRAIN, SKELETAL OR CIRCULATORY SYSTEM
BODY PLAN
• VERY BASIC BODY PLAN
• RADIAL SYMMETRY
• ONLY TRUE ORGANS ARE GONADS
BODY PLAN
• 2 TISSUE LAYERS• ECTODERM – OUTER COVERING
• ENDODERM – INNER LINING• CONNECTED TO EACH OTHER BY
MESOGLEA
• NON-CELLULAR JELLYLIKE MATERIAL
PHYSIOLOGY
• HAVE A NERVE NET AND BASIC RECEPTORS FOR IMPULSES TO MOVE
• OXYGEN TAKEN IN DIRECTLY THROUGH TISSUES FROM WATER COLUMN
• TENTACLES MAY BE METERS IN LENGTH & CARRY POISONS THAT CAUSE SEVERE PAIN OR DEATH
MOST DANGEROUS JELLYFISH
• WHEN THESE STINGER CELLS ARE TRIGGERED THE INTERNAL PRESSURE BUILDS UP TO A MASSIVE 2,000 PSI (136 ATMOSPHERES)
• WHEREUPON IT BURSTS, FIRING OUT A TOXIN HARPOON
• THIS IS ONE OF THE FASTEST MOVEMENTS IN NATURE AND QUICKER THAN A BULLET.
LIFE CYCLE
• HAVE BOTH ASEXUAL POLYPS & SEXUAL MEDUSA STAGES IN THEIR LIFE CYCLES
• ADULT MEDUSA STAGE RELEASES EGGS & SPERM INTO WATER
LIFE CYCLE
• FERTILIZATION PRODUCES CILIATED PLANULA LARVA THAT SETTLES TO THE BOTTOM, ATTACHES, & FORMS TENTACLES
• NEW MEDUSA BUD OFF OF REPRODUCTIVE POLYPS & FORM ADULT JELLYFISH
LIFE CYCLE
• UNLIKE CORALS, SPEND MOST OF THEIR LIFE IN MEDUSA STAGE
• RANGE IN SIZE OF 2MM-30M LONG
Jellies
Corals
LIFE CYCLE
• MEDUSA FORMS ARE USUALLY FREE-SWIMMING
• BELL-SHAPED ANIMALS WITH TENTACLES THAT HANG DOWN AROUND THE MOUTH
• THICK LAYER OF MESOGLEA FOR SUPPORT
LION’S MANE JELLYFISH
LION’S MANE JELLYFISH