Chapter 7 - Marine Invertebrates

Chapter 7 - Marine Invertebrates

1. CHAPTER 7 MARINE INVERTEBRATES

2. Marine Invertebrates Vertebrates : animals with a backbone Invertebrates : animals without a backbone At least 97% of all species of animals are invertebrates

3. Sponges

4. Sponges Sponges belong to the phylum Porifera or “pore bearers” aggregations of specialized cells do not form true tissues or organs nearly all marine

5. Sponges sessile : living permanently attached to the bottom or some other surface

6. Sponges ostia : numerous tiny pores on the surface of the sponge allows water to enter and circulate through a series of canals where plankton and other organic matter are filtered out and eaten sponge cells are very plastic if separated, the cells can even regroup and form a new sponge

7. Sponges water is pumped into a larger feeding chamber lined with collar cells or choanocytes water leaves through osculum : large opening on the top of the sponge

8. Sponges

9. Sponges most have spicules : transparent siliceous or calcareous supporting structures of different shapes and sizes many have a skeleton of spongin : tough elastic fibers made of protein

10. Sponges amoebocytes : wandering cells, that secrete spicules and spongin

11. Sponges suspension feeders : animals that eat food particles suspended in water filter feeders : actively filter the food particles in the suspension deposit feeders : eat detritus that settles on the bottom

12. Sponges

13. Sponges Most produce asexually budding of new sponge Some use gemmules : survivor pods

14. Sponges Found almost everywhere in the world largest number are found in tropical waters encrusting sponges : form thin sometimes brightly colored growths on rocks or dead coral

15. Sponges – Economic Importance bath sponges still harvested in a few locations of the Gulf of Mexico and the eastern Mediterranean some produce potentially useful chemicals

16. Cnidarians

17. Cnidarians Phylum Cnidaria Also called coenlenterates over 9,000 species including sea anemones, jellyfish, corals

18. Cnidarians display radial symmetry : similar parts of the body are arranged and repeated around a central axis look the same from all sides no head, front, or back

19. Cnidarians cnidocytes : specialized cells used mainly for capturing prey

20. Cnidarians oral surface : where the mouth is located aboral surface : located in the opposite site of the mouth

21. Cnidarians

22. Cnidarians centrally located mouth surrounded by tentacles : slender finger-like extensions used to capture and handle food mouth opens into a gut where food is digested

23. Cnidarians capture food (small prey) by discharging nematocysts (or cnidae ): unique stinging structures found within cells in the tentacles

24. Cnidarians Occur in two basic forms - polyp or medusa

25. Cnidarians Polyp : a sac-like attached stage with the mouth and tentacles oriented upward sessile Ex. sea anemone

26. Cnidarians Medusa : Bell-like structure that resembles an upside-down polyp and is adapted for swimming motile, swimming Ex. jellyfish

27. Types of Cnidarians Hydrozoans Scyphozoans Anthozoans

28. Hydrozoans (polyps) Feathery bushy colonies of tiny polyps drifting colonies of hydrozoans are called siphonophores example: portuguese man-of-war (blue bubble or blue bottle) ( Physalia physalis )

29. Portuguese Man-of-War

30. Scyphozoans True jellies with medusa shapes that can reach up to 6 feet in diameter True Nematocysts are only found in Hydrozoans and Scyphozoans

31. Anthozoans lack medusa stage consists of solitary colonial polyps anemones corals seapens sea pansies

32. Bilaterally Symmetric Worms

33. Worms bilateral symmetry : the arrangement of the body parts in such a way that there is only one way to cut the body and create two identical halves ex. humans

34. Flatworms Phylum: Platyhelminthes dorsoventrally flattened (flat bellies and backs) 20,000 species of flatworms

35. Flatworms Turbellarians most common marine flatworms mainly live in or around the surface of other invertebrates (mollusks, crabs, etc)

36. Flatworms Flukes ( trematodes ) largest group of flatworms 6,000+ species all are parasites adults always live in a vertebrate larvae may inhabit invertebrates or smaller vertebrates such as fish

37. Flatworms Tapeworms ( cestodes ) parasitic long body made of repeating units live in the intestines of vertebrates

38. Ribbon Worms ( Nemertean Worms) Phylum: Nemertea outwardly resemble flatworms, slightly more complex more advanced intestinal system circulatory system proboscis : long fleshy tube used to entangle prey

39. Nematodes (roundworms) Phylum: Nematoda most are parastic a layer of muscles in the body wall pushes and squeezes against the fluid creating a hydrostatic skeleton Hydrostatic Skeleton : A system that uses water pressure against the body wall to maintain body shape and aid in locomotion provide support and aids in locomotion

40. Nematodes (roundworms) live in the flesh or muscle tissue which used to make sashimi, sushi, and cerviche if the fish is served raw or undercooked, human infection is possible

41. Segmented Worms (annelids) Phylum: Annelida earthworms and many marine worms Display segmentation segments act as a hydrostatic skeleton efficient crawlers and burrowers

42. Polychaetes (Bristle worms) Phylum: Annelida Class: Polychaeta each body segment has a pair of flattened extensions called parapodia “beyond/beside feet” which have stiff, often sharp bristles called setae Used for movement and breathing through gills on parapodia

43. Polychaetes (Bristle worms)

44. Oligochaetes Oligochaetes small worms found in mud and sand feed on detritus lack parapodia

45. Oligochaetes Leeches Class: Hirudinea live mainly in fresh water marine species can be found attached to marine fishes and invertebrates highly specialized annelida with a sucker at each end and no parapodia   Echiurans all marine similar to peanut worms in size and shape have a non-retractable, spoon-like (forked) proboscis deposit feeders Peanut Worms sipunculans 1 to 35 cm long (.4 to 14 inches) soft unsegmented bodies burrow in the bottom or move into empty shells when it becomes compact it resembles a large peanut

46. Molluscs Clams, Octopuses, and Snails

47. Molluscs Phylum: Mollusca more species of mollusca than any other animal group around 200,000 living species

48. Molluscs most have soft bodies encased in a calcium carbonate shell live in marine, freshwater and terrestrial environments

49. Molluscs cephalopods (squid, cuttlefish, octopus) most neurologically-advanced of all invertebrates gastropods (snails and slugs) are the most numerous division giant or colossal squid are the largest known invertebrate species

50. Molluscs The body is covered by a mantle : a thin layer of tissue that secretes the shell usually bilaterally symmetric ventral, muscular foot usually used for locomotion

51. Molluscs most have a head with eyes and additional sensory organs Radula : a ribbon of small teeth (unique to molluscs ) or rasping tongue made mainly of chitin

52. Molluscs gas exchange occurs through paired gills shell is modified (internal for squid, octopod; external for gastropods)

53. Gastropods

54. Gastropods class - Gastropoda largest, most common, and most varied group includes snails, periwinkles, limpets, abalones

55. Gastropods a coiled collection of organs enclosed by a dorsal shell shell rests on a ventral foot varied shell structure and size

56. Gastropods carnivorous gastropods prey on clams, oysters worms and even small fishes other gastropods are detritivores

57. Gastropods Nudibranchs or sea slugs - gastropods that have lost their shell entirely nudibranchs

58. Bivalves

59. Bivalves class - Bivalvia includes clams, mussels, oysters, scallops

60. Bivalves have two-part shells each part is called a valve symmetric along the hinge line no head no radula inner surface of the shell is lined by the mantle

61. Bivalves gills are used for gas exchange and filter feeding strong muscles in the mantle cavity are used to open and close the valves

62. Oysters Most commercially valuable for pearls Form when the oysters secrete layers of calcium carbonate coat an irritant or parasite lodges between the mantle and the inner surface of the shell

63. Clams Use foot to bury in sand or mud Draw water in and out of mantle through siphons Feed and maintain oxygen while still buried

64. Mussels Live mainly in the intertidal zone Attach to surface using strong, byssal threads (beard)

65. Scallops Highly prized food source 100 simple blue eyes around the valves

66. Cephalopods

67. Cephalopods class- cephalopoda specialized for locomotion adapted mollusc body plan for an active way of life (nearly all agile swimmers) include octopuses, squids, cuttlefish, nautilus

68. Cephalopods complex nervous system reduced inner shell or no shell at all all are marine or brackish no radula , but do have a two part beak

69. Cephalopods foot is modified into arms and tentacles large eyes usually set on sides of the head thick, muscular mantle

70. Cephalopods 2 to 4 gills water enters through the free edge of the mantle and leaves through the siphon or funnel a muscular tube formed by what remains of the foot

71. Nautilus

72. Nautilus the chambered nautilus is considered the most primitive living cephalopod, because of its shell dates back 450 million years

73. Nautilus shell is thin, double layered and pearly white inside with a dull white with reddish zebra stripe outside the shell is separated into chambers by the septa, made of shell material as it grows it creates new larger chambers 1 chamber every few weeks until it reaches 38 chambers

74. Nautilus occupies one body chamber strong, beak-shaped crushing jaws eat algae , fish, crabs, shrimp and other invertebrates

75. Nautilus large collection of tentacles arranged into two circles, an inner and an outer. the female has twice as many tentacles in its inner circle than the male

76. Squid

77. Squid has only a thin shell remnant (pen) within it’s mantle strengthened outer collagen sheath to maintain the mantle’s shape and size

78. Squid to swim, the squid fills the mantle cavity with water and then forces it outward through the funnel in a jet-propulsion like manner normally swims backwards, can swim forward by bringing all 8 arms together Humboldt Squid

79. Squid fins along the body help with stabilization large squids can reach speeds of 15-20 mph many species swim in schools

80. Squid 8 arms, 2 long tentacles covered in suckers: adhesive discs used for suction between the squid an another object tentacles only have suckers on the flattened end

81. Octopus

82. Octopus has lost shell entirely bag-like mantle located above the head also has a strengthened collagen sheath surrounding the mantle

83. Octopus does not normally swim prefers to remain in contact with a solid surface uses suckers on its 8 legs to push and pull itself along the surface most have 240 suckers on each arm Crawling

84. Octopus usually a solitary animal that lives in a permanent den or cave under rocks ink chromatophores : specialized cells used to help an organism change color Chromatophores in action

85. Cephalopod Feeding and Digestion

86. Feeding and Digestion separate mouth and anus all cephalopods are carnivores involves salivary and digestive glands to help break down food varied diets and complexity of digestive systems based on diet Hungry octopus

87. Feeding and Digestion crystalline style : an enzyme secreting rod found in the stomach of bivalves continually rotates food and helps in digestion

88. Feeding and Digestion most molluscs have an open circulatory system cephalopods have a closed circulatory system

89. Nervous System and Behaviors

90. Nervous System gastropods and bivalves do not have a single brain but several sets of ganglia cephalopods most complex allows for learning to occur and for rapid movement and color changing to avoid predation

91. Reproduction

92. Reproduction most reproduce sexually, some hermaphroditic cephalopods use a spermatophore cephalopods lack larva and have large yolk-filled eggs octopus protect eggs and female usually dies protecting young because she does not leave to eat herself

93. Reproduction Octopus mating

94. Arthropods

95. Arthropods Phylum: Arthropoda largest phylum of animals insects are dominant terrestrial group crustaceans are more common in marine environments

96. Arthropods segmented, bilaterally symmetric possess an exoskeleton : large, non-living external skeleton composed of chitin and secreted by the underlying layer of tissue

97. Arthropods provides protection, support and increased surface area for muscle attachment to grow, arthropods must molt

98. Crustaceans

99. Crustaceans chitinous skeleton hardened by calcium carbonate appendages specialized for swimming possess 2 pairs of antennae

100. Small Crustaceans - Copepods small, important to plankton use enlarged pair of antennae for swimming many are parasitic

101. Small Crustaceans - Barnacles filter feeders live attached to surfaces, including other living organisms covered in calcareous plates have feather-like filtering appendages called cirri actually legs used to sweep water

102. Small Crustaceans – Amphipods small curved body and flattened sideways less than 2 cm in length some live under larger organisms skin like lice, parasites

103. Small Crustaceans - Isopods about the same size amphipods dorsoventrally flattened ex. terrestrial pill bugs many are parasitic

104. Small Crustaceans - Krill Also called euphausids planktonic , shrimp-like up to 6 cm long (2.5 in) most are filter feeders swim in groups of billions of individuals

105. Decapods five pairs of legs or pereiopods the first is heavier - usually claws for feeding and defense

106. Decapods three pairs of maxillipeds near the mouth turned forward, and specialized to sort food and push it towards the mouth

107. Decapods well developed carapace encloses the part of the body called the cephalothorax the rest of the body is known as the body

108. Decapods shrimp and lobsters have laterally compressed bodies with distinct and elongated abdomens (the “tail”)

109. Decapods Decapods use their chelipeds for feeding and fighting Therefore they often lose a claw They are able to regenerate lost chelipeds

110. Decapods Also most arthropods have two distinct claws The larger is called the crusher claw And the thinner, more serrated one, is called the pincer or tearing claw

111. Decapods In many arthropods, such as lobsters, there are major structural difference between males and females 1. Claw size (larger in males) 2. Tail width (wider in females) 3. Texture of swimmerets (harder in males)

112. Decapods Reproduce sexually, using internal fertilization

113. Decapods Also in crabs, a male has a v shaped abdomen and a female has a u shaped abdomen

114. Shrimp Typically scavengers Varied life environments Mutualistic relationships with other organisms Shrimp 1 Shrimp 2

115. American Lobster ( Homarus americanus ) also known as the northern lobster, Atlantic lobster or Maine lobster family Nephropidae , commercial lobsters bottom dweller found in colder waters off the Atlantic coast of North America New England and Canada

116. Lobsters scavenger and predator solitary in rocks or caves, also nocturnal exoskeleton, which molts 2-3 times a year as a juvenile and once a year as an adult Blue Lobster Molt

117. Lobsters Heavy bodied with a large abdomen and huge chelipeds one is lost in an accident or a fight it will regenerate sold with one claw -“cull” Sold with no claws – “bullet”

118. Lobsters 4 pairs of walking legs ( pereiopods ) 4 sets of swimmerets ( pleopods ), extend across the body harder in males softer in females used to protect eggs

119. Lobsters feathery gills located on either side of the cephalothorax

120. Hermit Crabs hermit crabs are not true crabs scavengers hide in empty gastropod shells

121. Crabs abdomen is small and tucked under a compact and broad cephalothorax largest and most diverse group of decapods

122. Crabs highly mobile - much faster than lobsters move sideways when they’re in a hurry sideways movement can also be used to indicate mating ex. fiddler crab

123. Horseshoe Crabs not true crabs “living fossils” eyes being researched to improve vision errors in humans

124. Sea spiders

125. Lophophorates

126. Lophophorates Have a lophophore - feeding structure made of a set of ciliated tentacles arranged in a horseshoe-like shape

127. Lophophorates Three main types: Bryozoans - lace-like Phoronids - worm-like Lamp Shells - clam-like

128. Echinoderms

129. Echinoderms Phylum: Echinodermata Pentamerous Radial symmetry : Five-way symmetry

130. Echinoderms Water-vascular system : A network of water-filled canals sea stars sea urchins connect to a madreporite : a porous plate on the aboral surface

131. Echinoderms Tube feet : muscular extensions of the water-vascular system that often end in a sucker ampullae : muscular sacs that sometimes aid in the extension of tube feet

132. Echinoderms small nerve net similar to cnidarians ability to regenerate Comet : a sea star with one large regenerated arm

133. Echinoderms many spines and bumps - part of the endoskeleton give the nickname “spiny-skinned”

134. Echinoderms Four main types: Sea stars Brittle Stars Sea Cucumbers Sea Urchins

135. Sea Stars Class: Asteroidea five arms that radiate around a central disk

136. Sea Stars hundreds of tube feet extend from the oral surface along radiating channels on each arm call ambulacral grooves

137. Sea Stars the aboral surface of most sea stars is covered with spines modified into pincer like organs called pedicellariae most are predators of bivalves

138. Brittle Stars Class: Ophiuroidea star shaped body very long flexible arms lack an anus are detritivores

139. Sea Cucumbers Class: Holothuroidea superficially wormlike lack spines no radial symmetry

140. Sea Cucumbers oral and aboral surfaces are located on the ends deposit feeders move using five rows of tube feet use branched tentacles to gather food

141. Sea Cucumbers defense some secrete toxic substances some discharge, sometimes toxic, filaments from the anus to discourage predators some eviscerate : discharge the gut and other organs through the anus

142. Sea Urchins endoskeleton is round and rigid with movable spines and pedicellariae movement is based on tube feet and the movable spines joined to sockets of the exoskeleton

143. Sea Urchins grazers - sea weeds and grasses mouth has an intricate system of jaws and muscles called aristotle’s lantern used to bite off pieces

144. Sea Urchins live in rocky shores also includes sand dollars

145. Chordates Without a Backbone

146. Chordates without a backbone Phylum Chordata divided into three major groups (subphyla) two lack a backbone, one does not Protochordates : the invertebrate chordates, chordates without a backbone

147. Chordates without a backbone 4 characteristics needed to be a chordate: 1. single, hollow nerve chord that runs along the dorsal side of the body

148. Chordates with a backbone 2. pharyngeal gill slits - small openings along the anterior end of the gut pharynx in humans

149. Chordates without a backbone 3. notochord - flexible rod for support that lies between the nerve chord and the gut

150. Chordates Without a Backbone 4. post-anal tail - a tail that extends beyond the anus (coccyx in humans)

151. Chordates without a backbone

152. Chordates without a backbone

153. Chordates without a backbone also have a ventral heart in vertebrates the notochord is replaced by the backbone (vertebral column)

154. Tunicates

155. Tunicates Subphylum: Unichordata best known are sea squirts the notochord and tail are absorbed during metamorphosis

156. Tunicates difference between sponge is the protective tunic tunic : leathery or gelatinous outer covering not found on sponges filter feeders

157. Lancelets

158. Lancelets Subphylum Cephalochordata almost 3 in long laterally compressed and elongated body like a fish bottom dwellers filter feeders