BIOL2712 Study Guide - Final Guide: Coral Bleaching, Gastrovascular Cavity, Scyphozoa

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apricotseal718

25 Jun 2018

School

Flinders University

Department

BIOD Biodiversity and Conservation

Course

BIOL2712

Professor

Jeremy Robertson

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The Radiata: Cnidaria & Ctenophora

(Coelenterates)

The Radiata or Coelenterates

Used to be one phylum

oCoelenterates

Now divided into 2:

oCnidarian

oCtenophora

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Planes of Symmetry

Phylum Cnidaria “sting bearing”

Common names

oHydras, hellyfish, anemones, corals

Fossil  700 my

10,000 species

Distribution

oEntirely aquatic

oMostly marine

Cells Form True Tissues

Sac-like body of 2 forms:

oSessile polyp

oFree-floating medusa

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Diploblastic = 2 germ layers

Ectoderm

oEpidermis

oOuter skin

Endoderm

oGastrodermis “gut skin”

oInside gastrovascular cavity

Digestion

The Cnidaria all have internal space = gastrovascular cavity

oA single opening to act as a mouth and anus

Nervous System

Simple net nerve

Diffuse with synapses over whole body

Simple sensory organs

Reproduction

Asexual

Budding of polyps

Fission

oPedal laceration – anemones

Sexual

Via gametes (medusae, some polyps)

oVia dioecious

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Document Summary

Sac-like body of 2 forms: sessile polyp, free-floating medusa. Endoderm: gastrodermis gut skin , inside gastrovascular cavity. The cnidaria all have internal space = gastrovascular cavity: a single opening to act as a mouth and anus. Via gametes (medusae, some polyps: via dioecious. Having male and female reproductive organs in separate individuals. Fertilized egg forms a blastomere: indeterminate cleavage. Planula larvae: note: larvae and adults have radial symmetry. Each contains a nematocyst: trigger, barbs and toxin. Secondary: intracellular via phagocytosis of particles by some cells. Aided by movement and infolding to increase sa:v ratio. Exist as a polyp: medusa stage is absent. Exist as a medusa: polyp stage is reduced. Box jelly stings can be deadly if not immediately treated: excruciating pain leads to: First aid: call ambulance, apply vinegar to stings, remove tentacles with tweezers only, administer spr if necessary. Biodiversity equivalent to rain forests on land: tourism. Some interesting products: e. g. bone grafts, sunscreens.