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  • PhylumCtenophora +Cnidaria

    Leonie Koch (10Jahre) 2013

  • Polyphyletic Origin of Sponges?

    Hexa

    ctine

    llida

    Biofilm/Protozoa Ancestral SymbiosisBasic Sponge Organisation

    Protozoa Outgroup

    (Choanoflagellata)

    Demospongiae

    Ancestral DemoHexDemospongic Acids

    coincidencies in 18s rDNA

    DemoHex Outgroup

    Cten

    opho

    ra

    Ancestral CtenoCalcNo Demospongic Acidssimilarities in 18sRNA

    Calcarea

    COOH(CH2)n

    DEMOSPONGIC ACIDS (C24-C32)

    Borchiellini et al. 2001(18s rDNA)

    Symbiotic Bacteria& few Archaea

    Symbiotic Archaea& few Bacteria

    JR 2005G GZ

    ?

  • Journal of Heredity 2014:105(1):118doi:10.1093/jhered/est084

  • Placozoa: Only one species:

    Trichoplax adhaerens

  • PoriferaPorifera

    CnidariaCnidaria

    CtenophoraCtenophorametazoametazoa

    parazoaparazoa

    mesodermallymesodermally derived musclesderived muscles acetylcholineacetylcholine--based nervous systembased nervous system

    eumetazoaeumetazoa

    triploblastictriploblastic

    diploblasticdiploblastic

  • PoriferaPorifera

    MetazoaMetazoa

    diploblasticdiploblastic -- muscle tissue associated muscle tissue associated with with gastrodermisgastrodermis or epidermisor epidermis

    cnidocytescnidocytes

    CnidariaCnidaria

    EumetazoaEumetazoa

    diploblasticdiploblastic

  • Ctenophora (Comb Jellies)

  • Ryan et al Science, 243, 2013

  • Ryan et al Science, 243, 2013

  • Ryan et al Science, 243, 2013

  • Ctenophores and CnidariansMay be known as far back as Precambrian Ediacaran organisms Hydroskeletons Pneus!

  • Ctenophores and CnidariansMay be known as far back as Precambrian Ediacaran organisms Hydroskeletons Pneus!

    Shu DG, Morris SC, Han J, Li Y, Zhang XL, Hua H, Zhang ZF, Liu JN, Guo JF, Yao Y, Yasui K (2006) Lower Cambrian vendobionts from china and early diploblastevolution. Science 312(5774):731-4

    Stromatoveris

  • Ctenophores comb jelly fish

    Maotianoascus octonarius from Lower Cambrian Maotianshan shale at Mt. Maotian, Chengjiang, Yunnan. (Scale bars, 10 mm.) (A and B) Part and counterpart of the holotype in this species. (C) A paratype specimen of this species. ST, statolith; CR, comb row; MC, meridional canal; SK, skirt-like possible oral lobe.

    Chen et al. 10.1073/pnas.0701246104.

  • Ctenophores and CnidariansMay be known as far back as Precambrian Ediacaran organisms Hydroskeletons Pneus!

    VINN O. & ZATO M. (2012).- Inconsistencies in proposed annelid affinities of early biomineralizedorganism Cloudina(Ediacaran): structural and ontogenetic evidences.- Carnets de Gologie [Notebooks on Geology], Brest, Article 2012/03 (CG2012_A03), p. 39-47

    The way of asexual reproduction in Cloudina resembles more that of cnidarians. The presence of a closed tube origin (base) in Cloudina is also compatible with the hypothesis of an animal of cnidarian grade.

  • Velella velella - By the wind sailorChondrophore Porpitid, Hydrozoan

    Ovatoscutum concentricusEdiacaran age

  • Corals (class Anthozoa of the phyllum Cnidaria or Coelenterata) are an extant group of organisms related to jellyfish and sea anemones. This group possesses the following characteristics:

    1) Radially symmetric body plan (may be slightly modified)2) Aquatic3) Mostly marine (a few freshwater forms - e.g. hydra)4) 2 Body layers - ectoderm & endoderm (no mesoderm)5) Tentaculate6) Cnidoblasts - stinging cells lodged in the ectoderm

    Cnidarians come in two basic forms:

    1) Free swimming medusae

    Body stalk

    Tentacle

    2) Attached polyps.

    Cnidarian Body Plans

  • Cnidaria (Coelenterata or Corals)

    Two forms:

    Polyps and Medusa

    Polyps asexual

    Medusa - sexual

  • Movement

    The cnidarian body is capable of some kind of coordinated movement Both the epidermis and the gastrodermis possess nerve cells arranged in a loose network - nerve net (plexus), which innervate primitively developed muscle fibers that extend from the epidermal and gastrodermal cells Stimulus in one part will spread across the whole body via the network

  • Nutrition

    Cnidarians are carnivores with hydras and corals consuming plankton and some of the sea anenomes consuming small fishes

    They use they tentacles to capture prey and direct it toward the mouth so that it can be digested in the gastrovascular cavity via secretions from gland cells (extracellular digestion); some food is phagocytized by special cells and digestion occurs intracellularly

    The gastrovascular cavity exists as 1 opening for food intake and the elimination of waste

    There is no system of internal transport, gas exchange or excretion; all these processes take place via diffusion

  • Stinging Organelles

    Prey capture is enhanced by use of specialized stinging cells called cnidocytes located in the outer epidermis. Each cnidocyte has a modified cilium -cnidocil, and is armed with a stinging structure called a nematocyst. The undischarged nematocyst is composed of a long coiled thread When triggered to release, either by touch or chemosensation, the nematocyst is released from the cnidocyte and the coiled thread is everted Some nematocysts function to entangle the prey; others harpoon prey and inject a paralyzing toxin

  • Cnidaria (Coelenterata or Corals)Stinging cellsCnidocytes

  • Cnidaria (Coelenterata or Corals)Stinging cells or Cnidocytes

  • Box jellyfish, or sea wasp (Chironex fleckeri).

  • Reproduction

    One of the most amazing adaptations is the ability of some cnidarians to regenerate lost parts or even a complete body Asexual reproduction is common with new individuals being produced by budding Sea anenomes engage in a form of asexual reproduction called pedal laceration Cnidariand are dioecious Fertilization is external, with the zygote becoming a elongated, ciliated, radiallysymmetrical larva - planula larva

    Planula larva

  • Classification:

    Phylum: Cnidaria (or Coelenterata)

    Class: Hydrozoa(Hydroids includes sessile colonial reef-building forms with a calcareous skeleton, and large complex, floating colonies, such as Potuguese man o war)Precambrian-Recent)

    Class: Scyphozoa(Jellyfish solitary medusoids)(Precambrian-Recent)

    Class: Anthozoa(Corals and anemones solitary and colonial polyps)(Precambrian-Recent)

  • Class Hydrozoa Includes the solitary freshwater hydra; most are colonial and marine Typical life cycle includes both asexual polyps and sexual medusa stages; however, freshwater hydras and some marine hydroids do not have a medusa stage

    Solitary Hydras Freshwater hydras are found in ponds and streams occurring on the underside of vegetation Most possess a pedal disc, mouth, hypostome surrounded by 6-10 tenetacles Mouth opens to the gastrovascular cavity The life cycle is simple: eggs and sperm are shed into the water and form fertilized eggs; planula is by passed with eggs hatching into young hydras Asexual reproduction via budding

  • Colonial Hydrozoans - e.g., Obelia

    Possess a skeleton of chiton that is secreted by the epidermis All polyps in the colony are usually interconnected Two different kinds of individuals that comprise the colony: feeding polyps or gastrozooids (C) and reproductive polyps or gonozooids(B)

  • Life Cycle of Obelia Gonozooids release free swimming medusae Zygotes become planula larvae, which eventually settle to become polyp colonies

    The medusae of hydroids are smaller than those of jellyfishes (C. Scyphozoa) Also, the margin of the bell projects inward forming a shelf-like velum

  • Other Hydrozoans

    Portuguese man-of-war:Single gas-filled float with tentaclesTentacles house the polyps and modified medusae of the colony

  • Heterastridium conglobatumMiddle Norian, Bad Aussee

  • Class Scyphozoa

    Jellyfish

    The medusae are large and contain massive amounts of mesoglea The differ from the hydrozoanmedusa in that the lack a velumPossess four gastric pouches lined with nematocysts; these are connected with the mouth an the gastrovascular system

  • Gametes develop in gastrodermis of gastric pouches; eggs and sperm are shed through mouth Fertilized eggs develop into a planula larva; settles on substrate and develops into a polyp - scyphistoma Scyphistoma produces a series of polyps by budding - strobila The polyps undergo differentiation and are released from the strobila as free swimming ephyra Ephyra matures into an adult jellyfish

    Scyphozoan Life Cycle - Aurelia

  • Fossil medusa

    Rhizostomites admirandusTithonian, PfalzpaintLithographic Limestone

    NarcomedusaMarjum Formation (Utah) Middle Cambrian

    Krukowski Quarry, Mount Simon Sandstone Outlier, Mosinee,WisconsinMiddle Cambrian

  • Cnidaria: Corals

  • Class Anthozoa cont.

    Solitary anthozoans include sea anemones Most anthozoans are colonial (e.g. corals) and secrete external skeletons composed of calcium carbonate. Corals obtain much of their energy from microscopic photosynthetic green algae (zooxanthellae) or dinoflagellates that live symbiotically inside the cells of the coral

  • Septal insertion in scleractinian corals.

    The protocorallite possess 6 septa as in rugosans.

    Subsequent septa are inserted in cycles of 6 between all previous septa.

    Thus cycles of 6+6+12+24

  • Scleractinina

    Anis-RecentAragonitic Skeleton

    With exceptions!

  • Corals and their kin through time. The vertica