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Cephalopods

1. Dec 2012
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Cephalopods

  1. S B B 3023 - Bi o d i v e r s i t y An d E v o l u t i o n Of Pr o t i s t a An d A n i ma l i a NAME MATRIC NO NABILAH BINTI KOMARUDDIN D20101037466 NUR SYAFIQAH BINTI ABD KADIR D20101037567 NAZRATUL ILYANA BINTI MOHAMAD D20101037470 YANTIE BINTI MAKLIN D20101037471 RIDWAN BIN SHAMSUDIN D20101037472 MARIAMAH BINTI ARON D20101037477
  2. 1.Most advance, intelligent invertebrates (squid, nautilus, octopus, cuttlefish) 2. Included squid,octopus,nautilses and cuttlefish 3. have well developed senses and large brain (larger than those of gastropods) 4.All marine 5.All predators (giant squid is the largest invertebrate)
  3. 6. They can also change texture and body shape 7. Cephalopods have advanced vision, can detect gravity with statocysts, and have a variety of chemical sense organs 8. cephalopods lack a cornea, and have an everted retina 9.Most cephalopods possess chromatophores that is, coloured pigment 10.cephalopods have an ink sac, which can be used to expel a cloud of dark ink to confuse predators 11. closed circulatory system.3 heart
  4. 12.Nautiluses are the only extant cephalopods with an external shell 13.Shell variable – Nautilus –multi-chambered gas-filled shell Cuttlefish -cuttlebone –internal shell Squid –internal shell (pen) Octopus –no shell 14.Reproduction -Dioecious, internal fertilization, eggs fertilized by males then leave oviduct of female and land on sea floor
  5. Sh e l l
  6. • The earliest shells were straight cones. • Others had curved or coiled shell such as ammonoids and nautiloids. • The early nautiloid and ammonoid shell are heavy cause buoyancy by a series of gas chambers. (eg: Nautilus) • This enable the animal to swim while carrying its shell.
  7. • The shell of Nautilus is coiled but quite differ from gastropod. • Transverse septa divide the shell into internal chambers. • The living animal inhibits only the last chamber. • As it grows, it moves forward, secreting behind it new septum. • The chambers are connected by a cord of living tissue called siphuncle.
  8.  Cuttlefish have a small, coiled or curved shell, but it is entirely enclosed by the mantle. Cuttlefish  Squids have no shell. But leaving only a thin, flexible strip called a pen, which the mantle enclosed. squids  Octopus have no shell. Octopus
  9. Bo d y a n d Ma n t l e
  10. NAUT I L US  the head with its tentacles can be extruded from the opening of the body compartment of the shell. Its 60-90 or more tentacles have no suckers but adhere to prey by secretions. The tentacles search for, sense and grasp food. The head is the funnel. The shell shelters the mantle, mantle cavity and visceral mass.
  11. Ot h e r t h a n Na u t i l o i d s Have only one pair of gills. Octopuses have 8 arms with suckers. Squids and cuttlefishes have 10 arms (8 out of 10 with suckers and the other 2 is retractile tentacles.) Thick mantle allowing water to be taken into the mantle cavity
  12. Ce p h a l o p o d s  They have a closed circulatory system with a network of vessels.  Blood flows through the gills via capillaries.  Branchial (gill) hearts, or accessory hearts increase the blood pressure in the gills which permits more rapid gas exchanges.  Have well-developed nervous systems-most complex brain among invertebrates.  Nautilus has simple eyes but others have elaborate eyes with cornea, lens, chambers and a retina.
  13. COL OUR CHA NGE S  Cephalopods has special numerous pigment- filled bags called chromatophores in the skin.  Chromatophores are found in the skin, and expand and contract to reveal or conceal small dots of color.  Color changes in cephalopods is controlled by the nervous system and hormones.
  14.  The color changes are used for camouflage or to startle and warn potential predators in their undersea realm. Cephalopods are believed has lack color vision, it is proven in the experiments.  The photoreceptor of cephalopods are rhabdomere cells. Hence, their ability to see color depends on the number of pigments present.
  15. The sac contains an ink Most cephalopods have gland that secretes a an ink sac that empties dark fluid containing the into the rectum. pigment melanin. The fluid is released through the anus to form a “smokescreen” to confuse an enemy.
  16. L o c o mo t i o n
  17. Swim by force expelling water from mantle cavity through ventral funnel. Funnel is mobile ( to control direction, forced expulsion of water determined speed)
  18. Sq u i d a n d c u t t l e f i s h In Squid (Loligo) and cuttlefish ( Sepia ) Streamlined (for speed) Lateral fins – acts as stabilizer, rapid swimming
  19. Na u t i l u s In Nautilus - Gas filled chambers keep shell upright Move slower compared to squid
  20. Oc t o p u s Has globular body, no fins Swim backward by spurting water from their funnel Aid to crawling over rocks Suction disc at arm- to anchor Some deep water octopus- have fins,arm webbed like umbrella, swim in medusae-like Large octopus- have flatten body and swim by undulation
  21. Re p r o d u c t i o n o f Cl a s s Ce p h a l o p o d a
  22. Sexes are separate Internal fertilization involves elaborate color changes cuttlefish
  23. Oc t o p u s Males changes in skin pigmentation and patterning Attract towards females and against rival males undergo copulation process
  24. Co p u l a t i o n pproduces a c e s s  Adult males r o special arm or modified arm called a hectocotylus  Then transfers a sperm packet to the female's pallial cavity  plucks a spermatophores from his own mantle cavity Arrow 1 : and inserts it into the The spermatophore mantle cavity of female groove of the inserted hectocotylus. near the oviduct Arrow 2 : opening An oviducal gland
  25.  The female lays a number of eggs  Some octopuse tends their eggs - guard their eggs  They clean them, provide them with fresh water and defend them against enemies  The female octopus does not eat as long a she guards the eggs. Often she dies after her offspring's hatching, because she is too weak to defend herself against her enemies
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  27. y a n d Ad a p t i v e d i v e r s i f i c a t i o n
  28. Ph y l o g e n y
  29. Ad a p t i v e di v e r s i f i c a t i on  Cephalopoda have a greatly expanded visceral mass.  In cephalopoda the mantle cavity was extended ventrally.  Evolution of chambered shell in cephalopodo was are very important contribution to their freedom from the substrate and their ability to swim.  Elaboration of their respiratory, circulatory, and nervous system is correlated with their predatory and swimming habits.  Diversity is related to their adaptation to different habitat, feeding methods and mode of life.
  30. END
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