Animal-Diversity. The Animal Diversity Web is an online database and encyclopedia of animal natural history, built through contributions from students, photographerspptx

The Animal Diversity Web is an online database and encyclopedia of animal natural history, built through contributions from students, photographers

1. General Biology- Zoology for BS Environmental Science Animal Diversity

2. Animal Diversity The animal world is large and diversified based on its members' shape, size, eating habit, habitat, method of reproduction. Animals show variations in their anatomy, physiology, and genetic features. Based on those differences, they are put into different categories. This diversification takes place due to the adaptation of each animal species to its surrounding environment. 2 1/8/2023 Animal Diversity- General Zoology

3. Animal Diversity Ecological diversity- It is an intricate connection between various types of species of the local ecosystem and the dynamic interplay between them. The ecosystem consists of organisms from different species that stay together in an area and their relationship builds up with the abiotic and biotic factors. . 3 1/8/2023 Animal Diversity- General Zoology

4. Animal Diversity Species diversity- This diversity exists within a habitat or a region. The term 'Species richness' indicates the total number of species in a particular geographical region. 4 1/8/2023 Animal Diversity- General Zoology

5. Animal Diversity Genetic diversity- It refers to the diversity of the genetic characteristics within a species. Genetic variation enables natural selection, depending upon the genetic information the animals share. The more characteristics they share, the more similar they appear. 5 1/8/2023 Animal Diversity- General Zoology

6. Animal Diversity Pattern of Classification In biology, the diversity in kingdom Animalia has expressed the classification of 36 distinct  animal phyla based on their evolutionary context. The most significant seven phyla are Porifera , Cnidaria , Platyhelminthes, Annelida, Mollusca, Arthropoda , and Chordata. The first six phyla are invertebrates. They do not possess a notochord in their body. The classification system differentiates the animals as per their superficial structure, morphology, evolutionary data, development at the embryo stage, and genetic features . It is a continuous process as the new species discovery is actively going on. 6 1/8/2023 Animal Diversity- General Zoology

7. Animal Diversity Phylum Porifera are the lowest multicellular animals belonging to the kingdom Animalia. The word “ Porifera ” mainly refers to the pore bearers or pore bearing species.  Based on the embryological studies, sponges are proved as animals and are classified into a separate Phylum in animals. This phylum includes about 5000 species. Poriferans are pore-bearing first multicellular animals. The pores are known as Ostia. The poriferans have a spongy appearance and are therefore called sponges. They are attached to the substratum and do not move (sessile).  They have the ability to absorb and withhold fluids. 7 1/8/2023 Phylum Porifera

8. Animal Diversity Phylum Porifera 8 1/8/2023 Phylum Porifera

9. Animal Diversity Phylum Porifera Characteristics of Poriferans 1. Multicellular ; body an aggregation of several types of cells differentiated for various functions,some of which are organized into incipient tissues of a low level of integration. 2. Body with pores (ostia), canals, and chambers that form a unique system of water currents on which sponges depend for food and oxygen 3. Mostly marine; all aquatic 4. Outer surface of flat pinacocytes ; most interior surfaces lined with flagellated collar cells ( choanocytes ) that create water currents; a gelatinous protein matrix called mesohyl contains amebocytes of various types and skeletal elements. 9 1/8/2023 Phylum Porifera

10. Animal Diversity Phylum Porifera Characteristics of Poriferans 5. Skeletal structure of fibrillar collagen (a protein) and calcareous or siliceous crystalline spicules, often combined with variously modified collagen ( spongin ) 6. No organs or true tissues; digestion intracellular; excretion and respiration by diffusion 7. Reactions to stimuli apparently local and independent in cellular sponges, but electrical signals insyncytial glass sponges; nervous system probably absent 8. All adults sessile and attached to substratum 9. Suspension or filter feeders 10. Asexual and sexual 10 1/8/2023 Phylum Porifera

11. Animal Diversity Phylum Porifera Three Classes of Phylum Porifera 1. Class Calcarea ( cal - ca‘re -a) (L. calcis , lime) ( Calcispongiae ). Have spicules of calcium carbonate that often form a fringe around the osculum (main water outlet); spicules needleshaped or three or four rayed; all three types of canal systems ( asconoid , syconoid , leuconoid ) represented; all marine.Examples : Sycon , Leucosolenia , Clathrina . 11 1/8/2023 Phylum Porifera

12. Animal Diversity Phylum Porifera Three Classes of Phylum Porifera 2. Class Hexactinellida (hex- ak -tin- el‘i -da) (Gr. hex, six, + aktis , ray, + L. - ellus , dim. suffix ) ( Hyalospongiae ). Have six-rayed, siliceous spicules extending at right angles from a central point; spicules often united to form network; body often cylindrical or funnel-shaped; fl agellated chambers in simple syconoid or leuconoid arrangement; habitat mostly deep water; all marine. Examples: Venus‘ flower basket ( Euplectella ), Hyalonema . . 12 1/8/2023 Phylum Porifera

13. Animal Diversity Phylum Porifera Three Classes of Phylum Porifera 3 .Class Demospongiae (de- mo - spun‘je -e) (Gr. demos, people, + spongos , sponge). Have siliceous spicules that are not six rayed, or spongin , or both; leuconoid -type canal systems; one family found in freshwater; all others marine. Examples: Thenea , Cliona, Spongilla , Myenia , Poterion , Callyspongia , and all bath sponges. 13 1/8/2023 Phylum Porifera

14. Animal Diversity Phylum Cnidarian ( ny-dar ̳e-a) (Gr. knide , nettle, + L. aria [pl. suffix], like or connected with) is an interesting group of more than 9000 species. It includes some of nature‘s strangest and loveliest creatures: branching , plantlike hydroids; flowerlike sea anemones; jellyfishes; and those architects of the ocean floor, horny corals (sea whips, sea fans, and others) and stony corals whose thousands of years of calcareous house-building have produced great reefs and coral islands. 14 1/8/2023 Phylum Cnidaria

15. Animal Diversity Phylum Cnidaria Characteristics of Cnidarians 1. Cnidocytes present, typically housing stinging organelles called nematocysts 2. Entirely aquatic, some in freshwater, but most marine 3. Radial symmetry or biradial symmetry around a longitudinal axis with oral and aboral ends; no definite head 4. Two types of individuals: polyps and medusae 5. Adult body two-layered (diploblastic) with epidermis and gastrodermis derived from embryonic ectoderm and endoderm, respectively. 6. Mesoglea, an extracellular matrix (―jelly‖) lies between body layers; amount of mesoglea variable; mesoglea with cells and connective tissue from ectoderm in some. 15 1/8/2023 Phylum Cnidaria

16. Animal Diversity Phylum Cnidaria Characteristics of Cnidarians 7 . Incomplete gut called gastrovascular cavity; often branched or divided with septa 8. Extracellular digestion in gastrovascular cavity and intracellular digestion in gastrodermal cells 9. Extensible tentacles usually encircle mouth or oral region 10.Muscular contractions via epitheliomuscular cells, which form an outer layer of longitudinal fibers at base of epidermis and an inner layer of circular fibers at base of gastro dermis; modifications of plan inhydrozoan medusa (independent ectodermal muscle fibers) and other complex cnidarians 11.Sense organs include well-developed statocysts (organs of balance) and ocelli (photosensitive organs); complex eyes in members of Cubozoa 16 1/8/2023 Phylum Cnidaria

17. Animal Diversity Phylum Cnidaria Characteristics of Cnidarians 12.Nerve net with symmetrical and asymmetrical synapses; diffuse conduction; two nerve rings in hydrozoan medusae 13.Asexual reproduction by budding in polyps forms clones and colonies; some colonies exhibit polymorphism 14.Sexual reproduction by gametes in all medusae and some polyps; monoecious or dioecious; holoblastic indeterminate cleavage; planula larval form 15.No excretory or respiratory system 16.No coelomic cavity 17 1/8/2023 Phylum Cnidaria

18. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 1.Class Hydrozoa (most variable class, including hydroids, fire corals, Portuguese man-of-war, and others). Class Hydrozoa (hi- dro - zo‘á ) (Gr. hydra, water serpent, + zōon , animal). Solitary or colonial; asexual polyps and sexual medusae , although one type may be suppressed; hydranths with no mesenteries; medusae (when present) with a velum; both freshwater and marine. Examples: Hydra, Obelia , Physalia , Tubularia . 18 1/8/2023 Phylum Cnidaria Obelia Hydra Fire Coral Portuguese man-of-war

19. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 2. Class Scyphozoa ( si-fo-zo‘a ) (Gr. skyphos , cup, + zōon , animal). Solitary; polyp stage reduced or absent; bell-shaped medusae without velum; gelatinous mesoglea much enlarged; margin of bell or umbrella typically with eight notches that are provided with sense organs; all marine. Examples: Aurelia, Cassiopeia , Rhizostoma . 19 1/8/2023 Phylum Cnidaria Aurelia Cassiopeia Rhizostoma

20. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 3. Class Staurozoa ( st ̇o- ro - zōá ) (Gr. stauros , a cross, + zōon , animal). Solitary; polyps only; medusa absent ; polyp surface extended into eight clusters of tentacles surrounding mouth; attachment via adhesive disc; all marine. Examples: Haliclystis , Lucernaria . 20 1/8/2023 Phylum Cnidaria Haliclystis , Lucernaria .

21. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 4.Class Cubozoa ( ku‘bo-zo‘a ) (Gr. kybos , a cube + zōon , animal). Solitary; polyp stage reduced; bell- shaped medusae square in cross section, with tentacle or group of tentacles hanging from a bladelike pedalium at each corner of the umbrella; margin of umbrella entire, without velum but with velarium ; all marine. They are also poisonous. Examples: Tripedalia , Carybdea , Chironex , Chiropsalmus . 21 1/8/2023 Phylum Cnidaria Tripedalia Carybdea , Chironex Chiropsalmus

22. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 5. Class Anthozoa (an- tho - zo‘a ) (Gr. anthos , flower, + zōon , animal). All polyps; no medusae ; solitary or colonial ; gastrovascular cavity subdivided by at least eight mesenteries or septa bearing nematocysts; gonads endodermal; all marine . There are sub-classes under class anthozoa (Subclass Hexacorallia , Subclass Ceriantipatharia , Subclass Octocorallia . 22 1/8/2023 Phylum Cnidaria

23. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 5.1 Subclass Hexacorallia - ( heks‘a - ko - ral‘e -a) (Gr. hex, six, + korallion , coral) ( Zoantharia ). With simple unbranched tentacles; mesenteries in pairs ; sea anemones, hard corals, and others. Examples: Metridium , Anthopleura , Tealia , Astrangia , Acropora , sea anemones, hard corals, and others 23 1/8/2023 Phylum Cnidaria Metridium , Anthopleura , Tealia , Astrangia , Acropora

24. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 5.2 Subclass Ceriantipatharia (se-re-an- tip‘a - tha‘re -a) (N. L. combination of Ceriantharia and Antipatharia ). With simple unbranched tentacles; mesenteries unpaired; tube anemones and black or thorny corals. Examples: Cerianthus , Antipathes , Stichopathes . 24 1/8/2023 Phylum Cnidaria Cerianthus Antipathes Stichopathes

25. Animal Diversity Phylum Cnidaria Four Classes of Phylum Cnidaria 5.3 Subclass Octocorallia ( ok‘to - ko - ral‘e -a) (L. octo , eight + Gr. korallion , coral) ( Alcyonaria ). With eight pinnate tentacles; eight complete, unpaired mesenteries; soft and horny corals. Examples: Tubipora , Alcyonium , Gorgonia , Plexaura , Renilla . 25 1/8/2023 Phylum Cnidaria Tubipora , Alcyonium , Gorgonia , Plexaura ,

26. Animal Diversity Phylum Annelida Phylum Annelida (an- nel‘i -da) (L. annelus , little ring, + ida , pl. suffix) consists of the segmented worms . It is a diverse phylum, numbering approximately 15,000 species, the most familiar of which are earthworms and freshwater worms (class Oligochaeta ) and leeches (class Hirudinida ). However, approximately twothirds of the phylum comprises marine worms (class Polychaeta), which are less familiar to most people. Some polychaetes are grotesque in appearance whereas others are graceful and beautiful . They include clamworms, plumed worms, parchment worms, scaleworms , lugworms, and many others . 26 1/8/2023 Phylum Annelida

27. Animal Diversity Phylum Annelida Characteristics of Phylum Annelida 1. Unique annelid head and paired epidermal setae present (lost in leeches); parapodia present in the ancestral condition 2. Marine, freshwater, and terrestrial 3. Most free-living, some symbiotic, some ectoparasitic 4. Body bilaterally symmetrical, metameric, often with distinct head 5. Triploblastic body 6. Coelom ( schizocoel ) well developed and divided by septa, except in leeches; coelomic fl uid functions as hydrostatic skeleton. 7. Epithelium secretes outer transparent moist cuticle 8. Digestive system complete and not segmentally arranged 27 1/8/2023 Phylum Annelida

28. Animal Diversity Phylum Annelida Characteristics of Phylum Annelida 9. Body wall with outer circular and inner longitudinal muscle layers 10. Nervous system with a double ventral nerve cord and a pair of ganglia with lateral nerves in each segment ; brain a pair of dorsal cerebral ganglia with connectives to ventral nerve cord 11. Sensory system of tactile organs, taste buds, statocysts (in some), photoreceptor cells, and eyes with lenses (in some); specialization of head region into differentiated organs, such as tentacles, palps, and eyespots of polychaetes . 12. Asexual reproduction by fission and fragmentation; capable of complete regeneration 13. Hermaphroditic or separate sexes; larvae, if present, are trochophore type; asexual reproduction bybudding in some; spiral cleavage and mosaic development. 28 1/8/2023 Phylum Annelida

29. Animal Diversity Phylum Annelida Characteristics of Phylum Annelida 14. Excretory system typically a pair of nephridia for each segment; nephridia remove waste from blood as well as from coelom 15. Respiratory gas exchange through skin, gills, or parapodia 16. Circulatory system closed with muscular blood vessels and aortic arches (―hearts‖) for pumping blood , segmentally arranged; respiratory pigments (hemoglobin, hemerythrin , or chlorocruorin ) oftenpresent ; amebocytes in blood plasma. 29 1/8/2023 Phylum Annelida

30. Animal Diversity Phylum Annelida Four Classes of Phylum Annelida Classification of annelids is based primarily on the presence or absence of parapodia , setae, and other morphological features. Because both oligochaetes and hirudineans (leeches) bear a clitellum, these two groups are often placed under the heading Clitellata (cli- tel - la‘ta ) and members are called clitellates . Alternatively , because both Oligochaeta and Polychaeta possess setae, some authorities place them together in a group called Chaetopoda ( ke - top‘o -da) (N.L. chaeta, bristle, from Gr. chaite ̄, long hair, + pous , podos , foot). 30 1/8/2023 Phylum Annelida Obelia Hydra Fire Coral Portuguese man-of-war

31. Animal Diversity Phylum Annelida Four Classes of Phylum Annelida 1.Class Polychaeta ( pol‘e-ke‘ta ) (Gr. polys, many, + chaite ̄, long hair). Mostly marine; head distinct and bearing eyes and tentacles; most segments with parapodia (lateral appendages) bearing tufts of many setae ; clitellum absent; sexes usually separate; gonads transitory; asexual budding in some; trochophore larva usually present. Examples: Nereis , Aphrodita , Glycera , Arenicola , Chaetopterus , Amphitrite, Riftia . 31 1/8/2023 Phylum Annelida Nereis , Aphrodita Glycera

32. Animal Diversity Phylum Annelida Four Classes of Phylum Annelida 1.Class Polychaeta ( pol‘e-ke‘ta ) (Gr. polys, many, + chaite ̄, long hair). Mostly marine; head distinct and bearing eyes and tentacles; most segments with parapodia (lateral appendages) bearing tufts of many setae ; clitellum absent; sexes usually separate; gonads transitory; asexual budding in some; trochophore larva usually present. Examples: Nereis , Aphrodita , Glycera , Arenicola , Chaetopterus , Amphitrite, Riftia . 32 1/8/2023 Phylum Annelida Arenicola Chaetopterus Amphitrite Riftia .

33. Animal Diversity Phylum Annelida Four Classes of Phylum Annelida 2.Class Oligochaeta ( ol‘i -go- ke‘ta ) (Gr. oligos , few, + chaite ̄, long hair). Body with conspicuous segmentation ; number of segments variable; setae few per segment; no parapodia ; head absent; coelom spacious and usually divided by intersegmental septa; hermaphroditic; development direct, no larva; chiefly terrestrial and freshwater. Examples: Lumbricus , Stylaria , Aeolosoma , Tubifex . 33 1/8/2023 Phylum Annelida Lumbricus Stylaria Aeolosoma Tubifex

34. Animal Diversity Phylum Annelida Four Classes of Phylum Annelida 3. Class Hirudinida ( hir‘u - din‘i -da) (L. hirudo , leech, + ida , pl. suffix): leeches. Body with fixed number of segments (normally 34; 15 or 27 in some groups) with many annuli; oral and posterior suckers usually present ; clitellum present; no parapodia ; setae absent (except in Acanthobdellida ); coelom closely packed with connective tissue and muscle; development direct; hermaphroditic; terrestrial, freshwater, and marine . Examples: Hirudo , Placobdella , Macrobdella 34 1/8/2023 Phylum Annelida Hirudo Placobdella Macrobdella

35. Animal Diversity Phylum Mollusca Mollusca ( mol-lus_ka ) (L. molluscus , soft) is one of the largest animal phyla after Arthropoda.There are over 90,000 living species and some 70,000 fossil species. Molluscs are coelomate protostomes , and as such they develop via spiral mosaic cleavage and make a coelom by schizocoely . The ancestral larval stage is a trochophore , but development is variously modified within the classes. The name Mollusca indicates one of their distinctive characteristics, a soft body. This very diverse group includes chitons, tusk shells, snails, slugs, nudibranchs, sea butterflies, clams, mussels, oysters , squids, octopuses, and nautiluses. 35 1/8/2023 Phylum Annelida

36. Animal Diversity Phylum Mollusca Characteristics of Mollusca 1. Dorsal body wall forms pair of folds called the mantle, which encloses the mantle cavity, is modified into gills or lungs, and secretes the shell (shell absent in some); ventral body wall specialized as a muscular foot, variously modified but used chiefly for locomotion; radula in mouth 2. Live in marine, freshwater, and terrestrial habitats 3. Free-living or occasionally parasitic 4. Body bilaterally symmetrical (bilateral asymmetry in some); unsegmented; often with definite head 5. Triploblastic body 6. Coelom limited mainly to area around heart, and perhaps lumen of gonads, part of kidneys, and occasionally part of the intestine. 1/8/2023

37. Animal Diversity Phylum Mollusca Characteristics of Mollusca 7. Surface epithelium usually ciliated and bearing mucous glands and sensory nerve endings 8. Complex digestive system; rasping organ (radula) usually present; anus usually emptying into mantle cavity ; internal and external ciliary tracts often of great functional importance 9. Circular, diagonal, and longitudinal muscles in the body wall; mantle and foot highly muscular in some classes (for example cephalopods and gastropods) 10. Nervous system of paired cerebral, pleural, pedal, and visceral ganglia, with nerve cords and subepidermal plexus; ganglia centralized in nerve ring in gastropods and cephalopods. 1/8/2023

38. Animal Diversity Phylum Mollusca Characteristics of Mollusca 11. Sensory organs of touch, smell, taste, equilibrium, and vision (in some); the highly developed direct eye (photosensitive cells in retina face light source) of cephalopods is similar to the indirect eye (photosensitive cells face away from light source) of vertebrates but arises as a skin derivative incontrast to the brain eye of vertebrates. 12. No asexual reproduction 13. Both monoecious and dioecious forms; spiral cleavage; ancestral larva a trochophore , many with a veliger larva, some with direct development 14. One or two kidneys ( metanephridia ) opening into the pericardial cavity and usually emptying into the mantle cavity. 1/8/2023

39. Animal Diversity Phylum Mollusca Characteristics of Mollusca 15. Gaseous exchange by gills, lungs, mantle, or body surface 16. Open circulatory system (secondarily closed in cephalopods) of heart (usually three chambered ), blood vessels, and sinuses; respiratory pigments in blood. 1/8/2023

40. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 1 . Class Caudofoveata ( kaw‘do - fo - ve -at‘ a) (L. cauda, tail, + fovea, small pit). Wormlike; shell, head , and excretory organs absent; radula usually present; mantle with chitinous cuticle and calcareous scales ; oral pedal shield near anterior mouth; mantle cavity at posterior end with pair of gills; sexes separate ; formerly united with solenogasters in class Aplacophora . Examples: Chaetoderma , Limifossor . 40 1/8/2023 Phylum Mollusca Chaetoderma Limifossor

41. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 2. Class Solenogastres (so- len‘o -gas‘ trez ) (Gr. solen , pipe, + gaster , stomach): solenogasters. Wormlike ; shell, head, and excretory organs absent; radula present or absent; mantle usually covered with calcareous scales or spicules; rudimentary mantle cavity posterior, without true gills, but sometimes with secondary respiratory structures; foot represented by long, narrow, ventral pedal groove; hermaphroditic. Example : Neomenia . 41 1/8/2023 Phylum Mollusca

42. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 3 . Class Monoplacophora ( mon‘o-pla-kof‘o-ra ) (Gr. monos , one, + plax , plate, + phora , bearing ). Body bilaterally symmetrical with a broad flat foot; a single limpetlike shell; mantle cavity with three to six pairs of gills; large coelomic cavities; radula present; three to seven pairs of nephridia , two of which are gonoducts ; separate sexes. Example: Neopilin . 42 1/8/2023 Phylum Mollusca

43. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 4. Class Polyplacophora ( pol‘y-pla-kof‘o-ra ) (Gr. polys, many, several, + plax , plate, + phora , bearing ): chitons. Elongated, dorsoventrally flattened body with reduced head; bilaterally symmetrical; radula present; shell of seven or eight dorsal plates; foot broad and flat; gills multiple along sides of body between foot and mantle edge; sexes usually separate, with a trochophore but no veliger larva. Examples: Mopalia , Tonicella . 43 1/8/2023 Phylum Mollusca

44. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 5 . Class Scaphopoda ( ska - fop‘o -da) (Gr. skaphë , trough, boat, + pous , podos , foot): tusk shells. Body enclosed in a one-piece tubular shell open at both ends; conical foot; mouth with radula and contractile tentacles ( captacula ); head absent; mantle for respiration; sexes separate; trochophore larva. Example : Dentalium . 44 1/8/2023 Phylum Mollusca

45. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 6 . Class Gastropoda (gas- trop‘o -da) (Gr. gaster , stomach, + pous , podos , foot): snails and slugs.Body asymmetrical and shows effects of torsion; body usually in a coiled shell (shell uncoiled or absent insome ); head well developed, with radula; foot large and flat; one or two gills, or with mantle modified intosecondary gills or a lung; most with single atrium and single nephridium ; nervous system with cerebral,pleural , pedal, and visceral ganglia; dioecious or monoecious, some with trochophore , typically withveliger , some without pelagic larva. Examples: Busycon , Polinices , Physa , Helix, Aplysia . . 45 1/8/2023 Phylum Mollusca Busycon Polinices Physa

46. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 6 . Class Gastropoda (gas- trop‘o -da) (Gr. gaster , stomach, + pous , podos , foot): snails and slugs.Body asymmetrical and shows effects of torsion; body usually in a coiled shell (shell uncoiled or absent insome ); head well developed, with radula; foot large and flat; one or two gills, or with mantle modified intosecondary gills or a lung; most with single atrium and single nephridium ; nervous system with cerebral,pleural , pedal, and visceral ganglia; dioecious or monoecious, some with trochophore , typically withveliger , some without pelagic larva. Examples: Busycon , Polinices , Physa , Helix, Aplysia , poisonous snails. 46 1/8/2023 Phylum Mollusca Helix Aplysia poisonous snail ( Conus geographus )

47. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 7 . Class Bivalvia (bi- val‘ve -a) (L. bi, two, + valva , folding door, valve) ( Pelecypoda ): bivalves. Body enclosed in a two-lobed mantle; shell of two lateral valves of variable size and form, with dorsal hinge ; head greatly reduced, but mouth with labial palps; no radula; no cephalic eyes, a few with eyes on mantle margin; foot usually wedge shaped; gills platelike ; sexes usually separate, typically with trochophore and veliger larvae. Examples: Anodonta , Venus, Tagelus , Teredo . 47 1/8/2023 Phylum Mollusca Anodonta Venus Tagelus Teredo shipworms or tamelok in tagalog

48. Animal Diversity Phylum Mollusca Eight Classes of Phylum Mollusca 8. Class Cephalopoda ( sef‘a - lop‘o -da) (Gr. kephalë , head, + pous , podos , foot): squids, cuttlefish, nautilus , and octopuses. Shell often reduced or absent; head well developed with eyes and a radula; head with arms or tentacles; foot modified into siphon; nervous system of well-developed ganglia, centralized to form a brain; sexes separate, with direct development. Examples: Sepioteuthis , Octopus, Sepia. 48 1/8/2023 Phylum Mollusca squids cuttlefish nautilus octopuses