SLIDESMANIA.COM Phylum Annelida & Phylum Mollusca KHAIRUL BARIAH BINTI IZANI | MAR IYAH NABIHAH BINTI BAHRON | MUHAMMAD ZHAFIRUL ARIFF BIN ZAINOM | NUR SYAMINA HUSNA BINTI AZMAN | SN1 2PISMP| SCES 3253 KINGDOM ANIMALIA ACTIVITY 2 TOPIC 2 KINGDOM ANIMALIA
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SLIDESMANIA.COM CHARACTERISTICS OF ANNELIDS ● They have a long and segmented body. ● Annelids are bilaterally symmetrical. ● They are triploblastic. ● Also, they exhibit organ system grade of organisation, showing organ differentiation. ● The body is covered with a thin cuticle. ● They are coelomate. A body cavity or coelom is present. ● Annelids live in moist environments, moist soil, freshwater and marine water. ● They have parapodia and chitinous setae, used for locomotion. ● Their body appears red due to the presence of haemoglobin. ● Excretory and nervous systems are present. ● The digestive system is complete and developed. ● Respiration happens through the general body surface. ● These invertebrates have a true closed circulatory system. ● Sexes may be separate or united, wherein they are called hermaphrodites. ● Fertilization can be internal or external.
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SLIDESMANIA.COM HOW ANNELIDS MOVE? The process of locomotion is a cumulative effect of contraction & relaxation of both the muscle layers of the body wall coordinated by the nervous system aided by setae hydrostatic pressure created by the coelomic fluid.
SLIDESMANIA.COM 1. During forward movement, circular muscles at the interior end contract due to an increase in the hydrostatic pressure of the anterior segments; this wave-like contraction then passed backwards 2. This results the anterior region to extend forward and at the same time making it thinner in diameter 3. The anterior end now grips the substratum & the setae acts as hooks by their posteriorly directed points 4. When the wave of contraction nears the mid-region of the body, circular muscles relax & longitudinal muscles of the anterior end causing the posterior body of the worm to be dragged forward. 5. The setae are extended to prevent backward movement of the segment 6. The wave of contraction of the longitudinal muscles passes backwards 7. Again, a wave of contraction of circular muscle starts from the anterior end before the first one has reached to the posterior end 8. Thus, locomotion is brought about by alternate contractions of circular & longitudinal muscles causing wave of thinning and thickening to pass backward 9. This involves partly a pushing of the anterior end and partly a pulling of the posterior end, the setae playing an accessory
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SLIDESMANIA.COM ERENTIANS Sedentaria is a diverse clade of annelid worms. It is traditionally treated as a subclass of the paraphyletic class Polychaeta, but it is also a monophyletic group uniting several polychaetes and the monophyletic class Clitellata. It is the sister group of Errantia. Alitta virens Sandworms eat seaweed and microorganisms. They have many distinctive traits, including: ● often reaching great lengths, sometimes exceeding four feet numerous, ● highly vascularized parapodia along both sides of their bodies ● blue heads with two large pincer teeth which are capable of biting humans. The parapodia function both as external gills (the animal's primary respiratory surfaces), and as means of locomotion (appearing much like short legs). Errentians is an annelid worm that burrows in wet sand and mud. It was first described by biologist Michael Sars in 1835. It is classified as a polychaete in the family Nereididae. Sandworms make up a large part of the live sea-bait industry. Usually, sandworms are gonochoric, meaning that they reproduce sexually between the males and females of the species. Sandworms reproduce via a process termed 'swarming'. The female sandworm releases pheromones that attract males to release sperm. Then, the female sandworm ejects eggs to have them fertilized. The production of gametes occurs via the metanephridia gland. https://en.wikipedia. org/wiki/Alitta_viren s
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SLIDESMANIA.COM KINGDOM ANIMALIA : PHYLUM MOLLUSCA KINGDOM MOLLUSCA
SLIDESMANIA.COM DEFINITION ❏ The members of the Phylum Mollusca are soft-bodied animals, unsegmented with a distinct head, muscular foot and visceral lump. ❏ The study of Mollusca is known as Malacology. ❏ Molluscs are mostly seen in Marine and freshwater. They mostly possess organ system level of organisation. KINGDOM ANIMALIA
1 + 2 = 3 SLIDESMANIA.COM HISTORY OF PHYLUM MOLLUSCA ❖ The name Mollusca came from the Latin, “mollis” meaning “soft” and this term was first used by the French Zoologist Cuvier in 1798 to describe squids and cuttlefish, an animal whose shell is reduced internal or entirely absent. ❖ It was only later that the true affinities between these species and other mollscus, such as snails and bivalves were fully recognized. ❖ Over 160000 species have been described, of which around 128000 are living and about 35000 are recorded as fossil species. The study of molluscs is known as Malacology and the study of the molluscan shell is known as Conchology. PHYLUM MOLLUSCA
SLIDESMANIA.COM CHARACTERISTICS OF PHYLUM MOLLUSCA These are mostly marine habitats, and some are freshwater habitats. They are triploblastic, bilaterally symmetrical with organ system level of organization The body is represented by a soft visceral mass that encloses all the internal organs The shell is secreted by the mantle and is made up of calcium. Shell may be external or internal (e.g., squid, cuttlefish) or absent (e.g., Octopus) The coelom is greatly reduced. It is restricted to the pericardial cavity and to small spaces within kidneys and gonads. Spaces amongst the viscera contain blood and form haemocoel Excretory organs are in the form of structures called organs of Bojanus. Ammonia is the chief excretory matter They have an open type circulatory system. It includes the dorsal heart, arteries that open into sinuses and veins Blood is usually blue due to the presence of a copper-containing blue respiratory pigment called haemocyanin. The sexes are separate, and fertilization is internal. They are oviparous. The development is either direct or indirect Some molluscs have Osphradium for testing the chemical and physical nature of water In many molluscs, eyes (photoreceptors) and tentacles are present on the head. KINGDOM ANIMALIA
SLIDESMANIA.COM CLASSIFICATION OF PHYLUM MOLLUSCA Monoplacophora Amphineura Scaphopoda Gastropoda Pelecypoda Cephalopoda
SLIDESMANIA.COM Monoplacophora ● They are bilaterally symmetrical with a dome-shaped mantle. ● These are marine habitats with internal segmentation. ● Flattened limpet-shaped shell with spirally coiled protoconch. ● Five pairs of gills in pallial grooves. ● The radula is in a radular sac and the intestine is coiled. ● Heart of two pairs of auricles and a single ventricle. ● Example: Neopilina galatheae Amphineura ● These are marine and have an elongated body with a reduced head. ● These have radula. The foot is ventral, large, flat and muscular. ● Shell as 8 dorsal plates or as spicules. ● Non-ganglionated nerve ring around the mouth with two pairs of interconnected nerve cord. ● External fertilization: trochophore larva. ● Example: Neomenia, Lepidopleurus, etc.
SLIDESMANIA.COM Scaphopoda ● These are marine habitats. ● The body is bilaterally symmetrical, elongated and enclosed in a tusk-shell that opens at both ends. ● They do not possess a head; mouth with tentacles; no eyes. ● They have a conical foot, the radula is present and gills are absent. ● Mantle tubular completely enclosing the body. ● Mouths are surrounded by lobular processes or outgrowths. ● Heart rudimentary. ● The kidneys are paired. ● Sexes are separate (dioecious). ● Trochophore larva. ● Examples: Dentalium, Cadulus, Pulsellum.
SLIDESMANIA.COM Gastropoda ● It is the largest class of Mollusca. ● Mostly they are marine, some are freshwater or terrestrial. ● The shells are present or may be absent in some; univalve and usually coiled. ● They have a well-developed head with eyes and tentacles, radula is also present. ● The foot is large and flat. ● The digestive system has the muscular pharynx, a long oesophagus, stomach, long coiled intestine, and anteriorly placed anus. ● Respiration by gills in most forms and through the wall of the mantle cavity in some animals. ● The open circulatory system and heart is enclosed in a pericardium. ● Sexes separate, they are dioecious in most molluscs. ● Examples: Pila, Bulla, Limax, etc.
SLIDESMANIA.COM Pelecypoda ● These are mostly marine and some are freshwater habitats. ● The body is enclosed in a bivalve shell and laterally compressed. ● They do not have a head, tentacles, eyes, jaws and radula. ● Gills or ctenidia are paired, one on each side. ● Their alimentary canal is coiled with large paired digestive glands. ● Sexes are separate or united. ● Mostly filter-feeding. ● Development is accompanied by metamorphosis which usually includes a trochophore larva. ● Examples: Ostrea, Mytilus, Unio, etc. Cephalopoda ● These are marine habitats and free-swimming animals. ● The body is elongated dorsoventrally and bilaterally symmetrical with the head and trunk. ● Head distinct and large with well-developed eyes and mouth. ● Example: Octopus.
SLIDESMANIA.COM Pila Classification of Pila : Kingdom: Animalia Phylum: Mollusca Class: Gastropoda Order: Architaenioglossa Genus: Pila Sepia Classification of Sepia Kingdom: Animalia Phylum: Mollusca Class: Cephalopoda Order: Sepiida Genus: Sepia Unio Classification of Unio Kingdom: Animalia Phylum: Mollusca Class: Bivalvia Order: Unionida Genus: Unio Examples of Phylum Mollusca
SLIDESMANIA.COM ECONOMIC Importance of Phylum Mollusca Molluscs like oyster, squid and cuttlefish are used as food in many countries The shell of many molluscs is of ornamental value, i.e., used in pearl extraction Dentalium is used as a decorative piece. Sepia ink has medicinal value. Shells of oyster are mixed with tar to make roads
SLIDESMANIA.COM REFERENCES Biology Online. (2022, July 12). Kingdom Animalia Definition and Examples - Biology Online Dictionary. Biology Articles, Tutorials & Dictionary Online. https://www.biologyonline.com/dictionary/kingdom-animalia Harshitha, A. (2023, January 25). Phylum Mollusca: Characteristics, Examples - Embibe. Embibe Exams. https://www.embibe.com/exams/phylum-mollusca/ Wasserman, S.A., Minorsky, P.V., Cain, M.L., Urry, L.A., & Orr, R. (2021). Campbell Biology. (12th ed.). Pearson. Audesirk, T., Audesirk, G., & Byers, B. E. (2017). Biology : Life on Earth with physiology (11th ed.). Pearson.