Post on 30-May-2015
SBB3023 - Biodiversity And Evolution Of Protista And Animalia
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
INTRODUCTION TO
CEPHALOPODA
SQUID NAUTILUS
CUTTLEFISH
OCTOPUS
CLASS CEPHALOPODA
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)
CHARACTERISTIC
CLASS CEPHALOPODA6. 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
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
Shell
• 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.
• 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.
Cuttlefish have a small, coiled or curved shell, but it is entirely enclosed by the mantle.
Squids have no shell. But leaving only a thin, flexible strip called a pen, which the mantle enclosed.
Octopus have no shell.
Cuttlefish
squids
Octopus
Body and Mantle
NAUTILUS 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.
Other than NautiloidsHave 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
CephalopodsThey 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.
COLOUR CHANGES
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.
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.
The fluid is released through the anus to form a “smokescreen” to
confuse an enemy.
Most cephalopods have an ink sac that empties
into the rectum.
INK PRODUCTIO
N
The sac contains an ink gland that secretes a
dark fluid containing the pigment melanin.
Locomotion
Swim by force expelling water from mantle cavity through ventral funnel.Funnel is mobile ( to control direction, forced expulsion of water determined speed)
Squid and cuttlefish
In Squid (Loligo) and cuttlefish ( Sepia )Streamlined (for speed)Lateral fins – acts as stabilizer, rapid swimming
NautilusIn Nautilus - Gas filled chambers keep shell uprightMove slower compared to squid
OctopusHas globular body, no finsSwim backward by spurting water from their
funnelAid to crawling over rocksSuction disc at arm- to anchorSome deep water octopus- have fins,arm
webbed like umbrella, swim in medusae-likeLarge octopus- have flatten body and swim by
undulation
Reproduction of
Class Cephalopoda
Sexes are separateInternal fertilizationinvolves elaborate color changes
cuttlefish
OctopusMales changes in skin pigmentation and
patterningAttract towards females and against rival
malesundergo copulation process
Copulation processAdult males produces a
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 and inserts it into the mantle cavity of female near the oviduct opening
Arrow 1 :The spermatophore groove of the inserted hectocotylus. Arrow 2 :An oviducal gland
The female lays a number of eggsSome octopuse tends their eggs - guard their eggsThey clean them, provide them with fresh water and
defend them against enemiesThe 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
1 2
3 4
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Phylogeny and Adaptive
diversification
Phylogeny
Adaptive diversification
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.
END