Chapter 7 - Marine Invertebrates

29. Apr 2016

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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  Sponges belong to the phylum Porifera or “pore bearers”  aggregations of specialized cells  do not form true tissues or organs  nearly all marine
  4. Sponges  sessile: living permanently attached to the bottom or some other surface
  5. 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
  6. 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
  7. Sponges
  8. 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
  9. Sponges  amoebocytes: wandering cells, that secrete spicules and spongin
  10. 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
  11. Sponges
  12. Sponges  Most produce asexually  budding of new sponge  Some use gemmules: survivor pods
  13. 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
  14. 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
  15. Cnidarians  Phylum Cnidaria  Also called coenlenterates  over 9,000 species including sea anemones, jellyfish, corals
  16. 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
  17. Cnidarians  cnidocytes: specialized cells used mainly for capturing prey
  18. Cnidarians  oral surface: where the mouth is located  aboral surface: located in the opposite site of the mouth
  19. Cnidarians
  20. 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
  21. Cnidarians  capture food (small prey) by discharging nematocysts (or cnidae): unique stinging structures found within cells in the tentacles
  22. Cnidarians  Occur in two basic forms - polyp or medusa
  23. Cnidarians  Polyp: a sac-like attached stage with the mouth and tentacles oriented upward  sessile  Ex. sea anemone
  24. Cnidarians  Medusa: Bell-like structure that resembles an upside- down polyp and is adapted for swimming  motile, swimming  Ex. jellyfish
  25. Types of Cnidarians  Hydrozoans  Scyphozoans  Anthozoans
  26. 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)
  27. Portuguese Man-of-War
  28. Scyphozoans  True jellies with medusa shapes that can reach up to 6 feet in diameter  True Nematocysts are only found in Hydrozoans and Scyphozoans
  29. Anthozoans  lack medusa stage  consists of solitary colonial polyps  anemones  corals  seapens  sea pansies
  30. 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
  31. Flatworms  Phylum: Platyhelminthes  dorsoventrally flattened (flat bellies and backs)  20,000 species of flatworms
  32. Flatworms  Turbellarians  most common marine flatworms  mainly live in or around the surface of other invertebrates (mollusks, crabs, etc)
  33. 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
  34. Flatworms  Tapeworms (cestodes)  parasitic  long body made of repeating units  live in the intestines of vertebrates
  35. 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
  36. 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
  37. 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
  38. Segmented Worms (annelids)  Phylum: Annelida  earthworms and many marine worms  Display segmentation  segments act as a hydrostatic skeleton  efficient crawlers and burrowers
  39. 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
  40. Polychaetes (Bristle worms)
  41. Oligochaetes  Oligochaetes  small worms found in mud and sand  feed on detritus  lack parapodia
  42. 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
  43. Clams, Octopuses, and Snails
  44. Molluscs  Phylum: Mollusca  more species of mollusca than any other animal group  around 200,000 living species
  45. Molluscs  most have soft bodies encased in a calcium carbonate shell  live in marine, freshwater and terrestrial environments
  46. 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
  47. 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
  48. 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
  49. Molluscs  gas exchange occurs through paired gills  shell is modified (internal for squid, octopod; external for gastropods)
  50. Gastropods  class - Gastropoda  largest, most common, and most varied group  includes snails, periwinkles, limpets, abalones
  51. Gastropods  a coiled collection of organs enclosed by a dorsal shell  shell rests on a ventral foot  varied shell structure and size
  52. Gastropods  carnivorous gastropods prey on clams, oysters worms and even small fishes  other gastropods are detritivores
  53. Gastropods  Nudibranchs or sea slugs - gastropods that have lost their shell entirely nudibranchs
  54. Bivalves  class - Bivalvia  includes clams, mussels, oysters, scallops
  55. 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
  56. Bivalves  gills are used for gas exchange and filter feeding  strong muscles in the mantle cavity are used to open and close the valves
  57. 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
  58. 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
  59. Mussels  Live mainly in the intertidal zone  Attach to surface using strong, byssal threads (beard)
  60. Scallops  Highly prized food source  100 simple blue eyes around the valves
  61. 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
  62. 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
  63. Cephalopods  foot is modified into arms and tentacles  large eyes usually set on sides of the head  thick, muscular mantle
  64. 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
  65. Nautilus  the chambered nautilus is considered the most primitive living cephalopod, because of its shell  dates back 450 million years
  66. 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
  67. Nautilus  occupies one body chamber  strong, beak-shaped crushing jaws  eat algae , fish, crabs, shrimp and other invertebrates
  68. 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
  69. Squid  has only a thin shell remnant (pen) within it’s mantle  strengthened outer collagen sheath to maintain the mantle’s shape and size
  70. 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
  71. Squid  fins along the body help with stabilization  large squids can reach speeds of 15-20 mph  many species swim in schools
  72. 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
  73. Octopus  has lost shell entirely  bag-like mantle located above the head  also has a strengthened collagen sheath surrounding the mantle
  74. 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
  75. 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
  76. 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
  77. Feeding and Digestion  crystalline style: an enzyme secreting rod found in the stomach of bivalves continually rotates food and helps in digestion
  78. Feeding and Digestion  most molluscs have an open circulatory system  cephalopods have a closed circulatory system
  79. 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
  80. 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
  81. Reproduction Octopus mating
  82. Arthropods  Phylum: Arthropoda  largest phylum of animals  insects are dominant terrestrial group  crustaceans are more common in marine environments
  83. Arthropods  segmented, bilaterally symmetric  possess an exoskeleton: large, non-living external skeleton  composed of chitin and secreted by the underlying layer of tissue
  84. Arthropods  provides protection, support and increased surface area for muscle attachment  to grow, arthropods must molt
  85. Crustaceans  chitinous skeleton hardened by calcium carbonate  appendages specialized for swimming  possess 2 pairs of antennae
  86. Small Crustaceans - Copepods  small, important to plankton  use enlarged pair of antennae for swimming  many are parasitic
  87. 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
  88. Small Crustaceans – Amphipods  small curved body and flattened sideways  less than 2 cm in length  some live under larger organisms skin like lice, parasites
  89. Small Crustaceans - Isopods  about the same size amphipods  dorsoventrally flattened  ex. terrestrial pill bugs  many are parasitic
  90. 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
  91. Decapods  five pairs of legs or pereiopods  the first is heavier - usually claws for feeding and defense
  92. Decapods  three pairs of maxillipeds near the mouth  turned forward, and specialized to sort food and push it towards the mouth
  93. Decapods  well developed carapace  encloses the part of the body called the cephalothorax  the rest of the body is known as the body
  94. Decapods  shrimp and lobsters have laterally compressed bodies with distinct and elongated abdomens (the “tail”)
  95. Decapods  Decapods use their chelipeds for feeding and fighting  Therefore they often lose a claw  They are able to regenerate lost chelipeds
  96. 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
  97. 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)
  98. Decapods  Reproduce sexually, using internal fertilization
  99. Decapods  Also in crabs, a male has a v shaped abdomen and a female has a u shaped abdomen
  100. Shrimp  Typically scavengers  Varied life environments  Mutualistic relationships with other organisms Shrimp 1 Shrimp 2
  101. 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
  102. 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
  103. 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”
  104. 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
  105. Lobsters  feathery gills located on either side of the cephalothorax
  106. Hermit Crabs  hermit crabs are not true crabs  scavengers  hide in empty gastropod shells
  107. Crabs  abdomen is small and tucked under a compact and broad cephalothorax  largest and most diverse group of decapods
  108. 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
  109. Horseshoe Crabs  not true crabs  “living fossils”  eyes being researched to improve vision errors in humans
  110. Sea spiders
  111. Lophophorates  Have a lophophore - feeding structure made of a set of ciliated tentacles arranged in a horseshoe-like shape
  112. Lophophorates  Three main types:  Bryozoans - lace-like  Phoronids - worm-like  Lamp Shells - clam-like
  113. Echinoderms  Phylum: Echinodermata  Pentamerous Radial symmetry: Five-way symmetry
  114. 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
  115. 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
  116. Echinoderms  small nerve net similar to cnidarians  ability to regenerate  Comet: a sea star with one large regenerated arm
  117. Echinoderms  many spines and bumps - part of the endoskeleton  give the nickname “spiny-skinned”
  118. Echinoderms  Four main types:  Sea stars  Brittle Stars  Sea Cucumbers  Sea Urchins
  119. Sea Stars  Class: Asteroidea  five arms that radiate around a central disk
  120. Sea Stars  hundreds of tube feet extend from the oral surface along radiating channels on each arm call ambulacral grooves
  121. 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
  122. Brittle Stars  Class: Ophiuroidea  star shaped body  very long flexible arms  lack an anus  are detritivores
  123. Sea Cucumbers  Class: Holothuroidea  superficially wormlike  lack spines  no radial symmetry
  124. 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
  125. 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
  126. 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
  127. 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
  128. Sea Urchins  live in rocky shores  also includes sand dollars
  129. 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
  130. 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
  131. Chordates with a backbone  2. pharyngeal gill slits - small openings along the anterior end of the gut  pharynx in humans
  132. Chordates without a backbone  3. notochord - flexible rod for support that lies between the nerve chord and the gut
  133. Chordates Without a Backbone  4. post-anal tail - a tail that extends beyond the anus (coccyx in humans)
  134. Chordates without a backbone
  135. Chordates without a backbone
  136. Chordates without a backbone  also have a ventral heart  in vertebrates the notochord is replaced by the backbone (vertebral column)
  137. Tunicates  Subphylum: Unichordata  best known are sea squirts  the notochord and tail are absorbed during metamorphosis
  138. Tunicates  difference between sponge is the protective tunic  tunic: leathery or gelatinous outer covering not found on sponges  filter feeders
  139. Lancelets  Subphylum Cephalochordata  almost 3 in long  laterally compressed and elongated body like a fish  bottom dwellers  filter feeders

Hinweis der Redaktion

  1. each choanocyte has a flagellum that creates currents and a thin collar that traps food, and then ingested by the body of the cell most have many oscula
  2. these two are found mainly between the outer and inner layers of cells
  3. also serve other uses such as food transport, food storage, cell repair and reproduction
  4. can extend proboscis up to 1m beyond their body one species reaches 30m (100ft) making it the longest invertebrate on earth
  5. most people immediately vomit the infected matter back up there are exceptions in which the larvae make it to the stomach or intestine cause symptoms similar to ulcers severe pain, nausea, muscle tearing and sometimes bleeding
  6. can be contracted in sequence by body wall muscles this and flexibility also given by segmentation makes annelids
  7. true circulatory system mainly carnivorous several pairs of eyes a proboscis, often jawed many polychaetes live in temporary or permanent tubes made of mucus, protein, seaweed, mud, sand or shell fragments
  8. previously called univalves gastropod literally means “stomach footed”
  9. “clusters of local brains” larger brain large never fibers that extend the length of the body