Who Am I

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Who Am I?

• What has no heart, bones, eyes or brain, is made
  up of 95 water, and yet is still a remarkably
  efficient ocean predator?

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A Jellyfish!

• With its stinging tentacles, this animal can kill
  its prey in a matter of minutes.
• If a jellyfish washes up on shore it also dies
  quickly when the water in its body dries out.

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Phylum CnidariaMeaningStinging Nettle

• Cnidarians (the c is silent) are aquatic,
  radially symmetric, and have two tissue layers
  (diploblastic).
• They have no complex organs. There are two body
  plan variations a floating medusa (e.g.
  jellyfish), and a sessile polyp (e.g. Hydra).
• Their nervous system is a diffuse nerve net.
• They have muscle-like fibers in their two cell
  layers, but no true muscles.
• They can locomote with their tentacles.
• They maintain their shape using a hydrostatic
  skeleton.

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Representatives
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Diagrams of Body Types

• Medusa shape

• A jellyfish's body generally comprises six basic
  parts
• The epidermis (outer layer), which protects the
  inner organs
• The gastrodermis, which is the inner layer
• The mesoglea, or jelly, between the epidermis and
  gastrodermis
• The gastrovascular cavity, which functions as a
  gullet, stomach, and intestine all in one
• An orifice (opening) that functions as both the
  mouth and anus
• Tentacles that line the edge of the body

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Diagrams of Body Types

• Polyp

• Polyps have the same basic body type as medusas,
  EXCEPT for the location of the mouth and the
  direction the tentacles point.

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Polyps
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Medusas
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Coral Polyps

• The coral is made of many tiny polyps similar to
  the polyp form of the sea anemone.

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Corals
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Coral Facts

• Coral polyps can be the size of a pinhead while
  others are larger, sometimes a foot in diameter.
• Each coral "tree" or "mound" is one  colony of
  coral polyps. One coral branch or mound is
  covered by thousands of these animals.
• The polyp uses calcium carbonate from seawater to
  build itself a hard, cup-shaped skeleton.  This
  limestone skeleton protects the soft, delicate
  body of the polyp.
• Coral polyps are usually nocturnal, meaning that
  they stay inside their skeletons during the day.
  At night, polyps extend their tentacles out to
  feed.
• Coral polyps eat in two different ways, depending
  on their species. Many coral polyps are nourished
  in a unique way by tiny algae.   Another way that
  corals eat is by catching tiny floating animals
  known as zooplankton. 

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Feeding

• They have no coelom, but they have a
  gastrovascular cavity (digestive sac) with only
  one opening.
• They feed by capturing prey using the tentacles
  surrounding their mouths. These tentacles have
  specialized cells (cnidocytes) containing
  stinging nematocysts.
• Prey are pulled into the gastrovascular cavity
  where they are digested. Cells obtain nutrients
  and get rid of wastes though simple diffusion.
• Jellyfish have no intestines, liver or pancreas
  which are so important in the digestion of food
  in most animals. Jellyfish don't produce bulky
  waste products, and those which they do produce
  are passed out through their large mouth. in
  fact, floating animals like the Jellyfish cannot
  afford to carry heavy items of food in their
  stomach while digestion takes place, because this
  would increase their weight, making it more
  difficult to stay afloat. Therefore, the
  Jellyfish digest their food and get rid of the
  waste matter very rapidly.

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Im Hungry!!
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Im Full!
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How the sting

• Each cell contains a tiny harpoon which, when
  triggered by touch or movement, shoots into the
  prey and delivers a debilitating toxin.
• The potency of this toxin varies among jellyfish,
  causing reactions in humans ranging from mild
  rashes to death.
• Jellyfish eat small animals such as shrimp and
  plankton. They also eat other Jellyfish of other
  species.

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Beautiful and deadly

• Right The Portuguese man-owar, known in
  Australia as the bluebottle because of its bluish
  transparent bubble, has stinging cells capable
  of killing small fish. In humans, stings can
  result in extreme localized pain (and respiratory
  distress in children or the elderly). Usually
  found washed ashore on beaches after rough
  weather, they can reach 30 cm (12 in) in size,
  with tentacles up to 10 m (33 ft) long, although
  they are commonly much smaller.
• The box jellyfish (sea wasp) is pale blue /
  transparent and has a cube-shaped bell, They are
  found in warmer waters around the world, though
  not usually over coral reefs. Pain from a sting
  is excruciating shock, respiratory arrest and
  death can follow within as little as 23 minutes.
• There are also comb jelliesthese look and act
  like jellyfish, but are not true jellies,
  because they have no stinging cells.

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Symbiosis

• Mutualism-two organisms help and benefit from
  each other.

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Symbiotic Examples

• The algae live within coral polyps, and do
  photosynthesis just like plants. Zooxanthellae
  use the polyp's wastes to get nutrients and
  return oxygen to the polyp. Meanwhile, the coral
  polyps provide the algae with carbon dioxide and
  a safe, protected home.
• Clown fish and sea anemones help each other with
  food and protection.

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How jellyfish move

• Some swim using jet propulsion.
• Some attach themselves by a stalk to other
  material, such as seaweed.
• Both types are referred to as zooplankton (animal
  drifters), because their movement is strongly
  influenced by the oceans current.
• Even jellyfish capable of jet propulsion are not
  strong enough swimmers to counter the power of
  the current and waves.

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Can coral or anemones move?

• Coral and sea anemones are essentially sessile (
  can not move)
• Their tentacles can flow in the water current
• Some can slide on the base the attach to

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Reproduction

• Individual Jellyfish are either male or female.
  The eggs and sperm develop in special areas
  called Gonads inside the body wall. The gonads
  are frequently very colorful and add greatly to
  the beauty of the living Jellyfish.
• When all of the eggs and sperm are fully
  developed, they are released into the stomach and
  then through the mouth into the sea.
• After the male releases its sperm through its
  orifice into the water, the sperm swim into the
  female's orifice and fertilize the eggs, which
  become an embryo and then a planula larva.
• Several dozen jellyfish larvae can hatch at once.
  They eventually float out on the currents and
  look for a solid surface on which to attach, such
  as a rock.
• When they attach they become polyps -- hollow
  cylinders with a mouth and tentacles at the top.
• The polyps later bud into young jellyfish called
  ephyrae.
• After a few weeks, the jellyfish float away and
  grow into mature medusae. A medusa can live for
  about three to six months.

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Respiration

• Jellyfish have no lungs or no gills or any
  special breathing organs. The walls of the body
  and tentacles are so thin that the oxygen
  molecules are able to pass directly from the
  water into the internal organs and the carbon
  dioxide molecules pass out of the body in the
  same way. Thus, one might say that a Jellyfish
  breathes with it's entire body.