13-1 CHAPTER 13 CHAPTER 13 Phylum Cnidaria Phylum Cnidaria
Dec 18, 2015
13-1
CHAPTER 13CHAPTER 13CHAPTER 13CHAPTER 13
Phylum CnidariaPhylum CnidariaPhylum CnidariaPhylum Cnidaria
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Phylum Cnidaria
Fossil specimensFossil specimens dated to over dated to over 700 million 700 million years agoyears ago
General Characteristics Soft bodied Carnivorous Stinging tentacles Examples: Jellyfish, sea anemones
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-4
Phylum CnidariaPhylum Cnidaria
Classes of CnidariaClasses of Cnidaria Hydrozoa (Portuguese Man-of-War, Hydra)Hydrozoa (Portuguese Man-of-War, Hydra) Scyphozoa (True Jellyfish - Aurelia)Scyphozoa (True Jellyfish - Aurelia) Anthozoa (Sea Anenome, Corals)Anthozoa (Sea Anenome, Corals)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-5
Phylum CnidariaPhylum Cnidaria
Characteristics of Phylum Cnidaria Characteristics of Phylum Cnidaria All areAll are aquatic aquatic and mostly marine and mostly marine SymmetrySymmetry
RadialRadial Two body typesTwo body types
Free-swimming medusa Free-swimming medusa Sessile polypsSessile polyps
Acoelomates - No coelomAcoelomates - No coelom Diploblastic Diploblastic Blind (Incomplete) GutBlind (Incomplete) Gut
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-6
Phylum CnidariaPhylum Cnidaria
Tentacles Tentacles usually encircle mouth or oral regionusually encircle mouth or oral region Equipped with specialized cells: Equipped with specialized cells: cnidocytes cnidocytes
CnidocytesCnidocytes: stinging cells located on their tentacles: stinging cells located on their tentacles NematocystNematocyst: : stinging organelle, poison-filled structure that stinging organelle, poison-filled structure that
contains a tightly coiled dart.contains a tightly coiled dart. Tactile stimulation of Tactile stimulation of cnidocilcnidocil, causes nematocyst to discharge, causes nematocyst to discharge After discharge, cnidocyte is absorbed and another developsAfter discharge, cnidocyte is absorbed and another develops
Mechanism of Nematocyst Discharge Mechanism of Nematocyst Discharge When stimulated, water rushes into the capsuleWhen stimulated, water rushes into the capsule The operculum (cap) opens and rapidly launches the filamentThe operculum (cap) opens and rapidly launches the filament Barbs Barbs inject poisoninject poison into prey into prey Only a Only a few jellyfish - and the Portuguese man-of-warfew jellyfish - and the Portuguese man-of-war can seriously can seriously
harm humansharm humans
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Cnidarian Phyla
Topical Solutions if stung: Topical Solutions if stung: acidic (vinegar) acidic (vinegar) Urine - only if urine is acidic?? Most urine is sterile.Urine - only if urine is acidic?? Most urine is sterile.Apply heat or ice for pain (also denatures toxins)Apply heat or ice for pain (also denatures toxins)Salt water should be applied to remove any excess toxins.Salt water should be applied to remove any excess toxins.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Discharged cnidae
recoiled
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-9
Phylum CnidariaPhylum Cnidaria
OTHER CNIDARIAN CHARACTERISTICSOTHER CNIDARIAN CHARACTERISTICS Sense organsSense organs for balance ( for balance (statocystsstatocysts) and ) and
photosensitivity (photosensitivity (ocelliocelli)) Nerve net Nerve net
Simple nervous system, no brainSimple nervous system, no brain Asexual reproductionAsexual reproduction
Budding in polypsBudding in polyps Sexual reproduction Sexual reproduction
By gametes in all medusa and some polypsBy gametes in all medusa and some polyps Monoecious or DioeciousMonoecious or Dioecious
No No excretory or respiratory systemexcretory or respiratory system
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-10
Life CyclesLife Cycles Typically, zygote develops into a motile Typically, zygote develops into a motile planula larvaplanula larva Planula settles, and metamorphoses into a Planula settles, and metamorphoses into a polyppolyp
Produce other polyps asexuallyProduce other polyps asexually Polyps eventually produce a free-swimming Polyps eventually produce a free-swimming
medusa by asexual reproduction medusa by asexual reproduction (Budding)(Budding)
Phylum CnidariaPhylum Cnidaria
HydrazoanLife Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-11
A. Hermit crab uses cnidarian as protectionB. Showing growth on host shell
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-12
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-13
Phylum CnidariaPhylum Cnidaria
Form and Function Form and Function Cnidaria have two basic body plans: Cnidaria have two basic body plans:
polyp and medusapolyp and medusa Polyp Polyp
Adaptation to a sedentary lifeAdaptation to a sedentary life Tubular body with the mouth directed upward Tubular body with the mouth directed upward
and surrounded by tentaclesand surrounded by tentacles Mouth leads into a Mouth leads into a blind-gutblind-gut cavity cavity Reproduce asexually by budding, fission, or Reproduce asexually by budding, fission, or
pedal lacerationpedal laceration
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-14
Phylum Cnidaria - MedusaPhylum Cnidaria - Medusa MedusaMedusa
Bell or umbrella-shapedBell or umbrella-shaped Usually free-swimmingUsually free-swimming Mouth directed downward Mouth directed downward Tentacles may extend down from rim of Tentacles may extend down from rim of
umbrellaumbrella
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-12
Phylum CnidariaPhylum Cnidaria
Body WallBody Wall Cnidarian bodyCnidarian body
Outer Outer epidermisepidermis Inner Inner gastrodermisgastrodermis (gastrovascular cavity = gut) (gastrovascular cavity = gut) Layers separated by Layers separated by mesogleamesoglea Mesoglea Mesoglea
Gelatinous (at least 95% water) - jellylikeGelatinous (at least 95% water) - jellylike Continuous, extending through body and Continuous, extending through body and
tentaclestentacles Supports bodySupports body Thickness variesThickness varies
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-16
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-17
Phylum CnidariaPhylum Cnidaria
Class HydrozoaClass Hydrozoa Most marine and colonial with both polyp and Most marine and colonial with both polyp and
medusa forms (polyp form dominates)medusa forms (polyp form dominates) ColonialColonial Obelia Obelia
Typical hydroid has a Typical hydroid has a base, a stalkbase, a stalk, and one or , and one or more individual polyp animalsmore individual polyp animals
Feeding polypsFeeding polyps with tentacles around mouth= with tentacles around mouth= hydranthshydranths
In Obelia, the medusa buds are formed by a In Obelia, the medusa buds are formed by a reproductive polypreproductive polyp called a called a gonangiumgonangium
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-18
Obelia Life Cycle
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-19
Hydroids
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-20
Bell medusa(Hydroid)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-21
Medusa
D. Developing Polyp from Planula: Frustule = bud
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-22
Freshwater Hydrozoan
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-23
Phylum CnidariaPhylum Cnidaria
Class Hydrozoa: AnimalsClass Hydrozoa: Animals HydraHydra
Found in Found in fresh waterfresh water Worldwide distributionWorldwide distribution (16 species in North America) (16 species in North America) Polyp body formPolyp body form Ring of 6–10 hollowRing of 6–10 hollow tentacles tentacles encircles mouth encircles mouth
Portuguese Man-of-WarPortuguese Man-of-War Floats on surface (air bladder)Floats on surface (air bladder) Tentacles reach up to 10 metersTentacles reach up to 10 meters Contains polyp colonies and medusaContains polyp colonies and medusa Air bladder contains gases releasedAir bladder contains gases released
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-24
Hydra catching a water flea
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-25
Hydra w/ developing bud and ovary/egg
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-26
Portuguese man-of-war ColonySecrete powerful neurotoxin - Class Hydrozoa (Many Polyps and medusa in colony)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Differences between Hydrozoa and Scyphozoa
Hydrozoa Colonial Stages Mostly Polyp life form Medusa, if present, are
usually small Small amounts of mesoglea Less tentacles
Scyphozoa Large Medusa forms Cells present in mesoglea More complex More tentacles Large amount of mesoglea
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-28
Phylum CnidariaPhylum Cnidaria
Class ScyphozoaClass Scyphozoa Most of the Most of the larger jellyfisheslarger jellyfishes belong to this belong to this
classclass Nearly all Nearly all float in open seafloat in open sea Bells vary in shape and sizeBells vary in shape and size
Composed mostly of Composed mostly of mesoglea mesoglea
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-29
Class Scyphozoa
Giant jellyfish-exceeds 2 Meters in diameter
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-30
Moon Jellyfish(Aurelia)
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-31
Phylum Cnidaria - ScyphozoaPhylum Cnidaria - Scyphozoa
Reproduction methodsReproduction methods Asexual - Similar to other cnidarians. BuddingAsexual - Similar to other cnidarians. Budding But also use But also use StrobilationStrobilation - asexual budding of - asexual budding of
saucerlike buds that develop into medusa.saucerlike buds that develop into medusa.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-32
Life Cycle of Aurelia, marine scyphozoan
Strobilation
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-33
Phylum CnidariaPhylum Cnidaria
Class AnthozoaClass Anthozoa Lack a medusa stageLack a medusa stage All marine,All marine, in both deep and shallow water, in both deep and shallow water,
and vary in sizeand vary in size Examples: sea anemones, sea coralsExamples: sea anemones, sea corals
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-34
Sea Anemones
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-35
Structure of Sea Anemone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-36
Phylum Cnidaria - AnthozoaPhylum Cnidaria - Anthozoa
Sea AnemonesSea Anemones Polyps larger and heavier than hydrozoan Polyps larger and heavier than hydrozoan
polypspolyps Attach to shells, rocks, timber, etc. by pedal Attach to shells, rocks, timber, etc. by pedal
discsdiscs Crown of tentacles surrounds the flat oral Crown of tentacles surrounds the flat oral
discdisc
When in danger,When in danger, water rapidly expelled through water rapidly expelled through pores as the anemone contracts to a small sizepores as the anemone contracts to a small size
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-37
Sea Anemone being attacked by a Sea Star
Can Sea Anemones run?
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-38
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-39
Tube Anemone
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-40
Phylum Cnidaria - AnthozoaPhylum Cnidaria - Anthozoa
Reproduction of Sea AnemonesReproduction of Sea Anemones Some Some dioecious,dioecious, some some monoeciousmonoecious Monoecious species - Monoecious species - produce sperm first and produce sperm first and
eggs latereggs later Fertilization is external or in gastrovascular Fertilization is external or in gastrovascular
cavitycavity Zygote becomes a Zygote becomes a ciliated larvaciliated larva Pedal laceration, small pieces of pedal disc Pedal laceration, small pieces of pedal disc
break off and regenerate a small anemonebreak off and regenerate a small anemone Budding can occur Budding can occur
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-41
Closed during day, open to feed at night
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-42
Polyp ofCoral
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-43
A Thorny Coral
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-44
A soft coral on Pacific Coral Reef
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-45
Sea Fan Red Whip CoralRed Gorgonian
Horny Coral Types
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-46
Phylum CnidariaPhylum Cnidaria
Coral ReefsCoral Reefs Great diversityGreat diversity of organisms (under rainforest) of organisms (under rainforest) Plants and animals are limited to top layer Plants and animals are limited to top layer
Above the calcium carbonate depositsAbove the calcium carbonate deposits Reef forming corals and algaeReef forming corals and algae precipitate calcium precipitate calcium
carbonatecarbonate to form most coral reefs to form most coral reefs Require warmth, light, and salinity of undiluted Require warmth, light, and salinity of undiluted
sea water (contains calcium)sea water (contains calcium) Photosynthetic zooxanthellaePhotosynthetic zooxanthellae live in their tissues live in their tissues Provide food for corals, carbon for calcium Provide food for corals, carbon for calcium
carbonate, and recycle phosphorus and carbonate, and recycle phosphorus and nitrogenous wastesnitrogenous wastes
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
13-47
Phylum Cnidaria - Human ImpactPhylum Cnidaria - Human Impact
Nutrients from fertilizer and sewage threaten coral Nutrients from fertilizer and sewage threaten coral reefs with excessive algal growth - or by killing reefs with excessive algal growth - or by killing zooxanthellae, which leads to coral bleaching.zooxanthellae, which leads to coral bleaching.
Persian Gulf reefs have withstood surprising Persian Gulf reefs have withstood surprising amounts of oil pollutionamounts of oil pollution
Coral reefs in many areas are threatened by factors Coral reefs in many areas are threatened by factors mostly of human originmostly of human origin
HUMAN IMPACT: