How do different animals breathe?

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How do different animals breathe?

• Lungs
• eg. Man, whale, seal, bat, snake, dog, cow
• Moist skin
• eg. Frogs, toads, salamander, earthworm
• Gills
• eg. Fish, tadpole, mudskipper
• Breathing tube
• eg. Wriggler, water stick insect
• Breathing holes
• eg. Ant, dragonfly

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Breathing Underwater
All animals breathe to obtain oxygen for their
bodies and to expel carbon dioxide. Animals which
live underwater have no problem in expelling
carbon dioxide because it dissolves very easily
in water. Their problem is how to obtain enough
oxygen.The amount of oxygen dissolved in the
water depends upon the water temperature but, in
general, we can say that if the water is at 15C
there is 30 times more oxygen in the air than in
water.
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Gills

• If the animal is not very active it could breathe
  through its skin as earthworms do on land. If,
  however, the animal is very active it may find
  that the skin does not let enough oxygen into the
  body. Animals which swim a lot need a
  considerable amount of oxygen to make the muscles
  work.More oxygen can enter the body if the skin
  has a greater surface. The skin can be given a
  bigger surface by making it stick out of the body
  as folds and projections. A gill is created when
  these folds and projections are given a blood
  supply.Because this type of gill sticks out
  into the water we call it an external gill. You
  can imagine that this type of gill could get in
  the way or be damaged if the animal moves around
  a lot.

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• Fishes have internal gills which are covered by
  an operculum. To get enough oxygen the fish must
  make water flow across its gills. The fish does
  not breathe water in and out of its mouth.

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• The drawing shows the water entering the fish's
  mouth and crossing the gills. 

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The above image is a close-up of one of the thin
channels in the fish's gills.The channel that the
water flows through is surrounded by blood
vessels, that flow in the opposite direction. The
oxygen leaves the water, and goes into the blood.
From there, it is carried all around the body of
the fish!
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• You can see that the fish's gills are feathery,
  which gives them a large surface. The gills also
  come in several layers. They can be very
  efficient at extracting oxygen from the water,
  allowing some fish to be very fast swimmers.

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gill rakers
gill arch
gill filaments
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• Like humans, fish have water-proof skin. This
  means they can't breathe through their skin like
  some other animals, like amphibians. Lungs don't
  work well in water, because it takes too much
  energy to move the water in and out of them.
  Instead, fish use their gills to get oxygen. Fish
  have a heart and circulatory system that is
  similar to that of humans, and it carries oxygen
  around to all the cells, just like in our bodies!

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Neat Stuff

• If there's oxygen in the water, then why can't
  humans breathe water? Because oxygen has to move
  from the water into our blood, which is much
  slower than when oxygen moves from the air into
  our blood. Gills are specialized to handle this
  slow movement, but our lungs can't pick up oxygen
  from the water fast enough to keep us alive,
  which is why we drown if we try to breathe water.

Resource http//lung.ca/children/grades4_6/respi
ratory/fish.html
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Many aquatic invertebrates also have gills.
Crustaceans, such as the crab, and molluscs, such
as the mussel breathe using gills. 

• A mussel also uses its gills for feeding. As
  the mussel sucks water into its shell to breathe,
  it also draws in the microscopic plankton which
  it filters and sends to its mouth. In this way a
  large mussel may pass 2,5 dm3 of water across its
  gills in an hour.

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The Tracheal Gill
The young larvae of aquatic insects also have a
kind of gill combined with their tracheal system.
It is called a tracheal gill.
The insects do not have blood vessels passing
through their gills, they have tracheae instead.
These tracheae are filled with air just like the
tracheae of air-breathing insects. They do not,
however, open onto the outside world through
spiracles. Instead they are completely closed
off. Oxygen passes from the water, crossing the
gills, and then moves into the air filled
tracheae. From there the gas is transported
around the body in the tracheal system.
Taken from http//www.saburchill.com/chapters/ch
ap0023.html
Breathing through skin http//www.saburchill.com
/chapters/chap0022.html