Caves

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					            Caves
A cave is defined as an underground
passage large enough for a person to
 crawl into, naturally formed, and in
         complete darkness.
        How does a cave form?
1.   Rain dissolves Carbon Dioxide into Carbonic acid
2.   Carbonic acid dissolves minerals in rock
3.   Rock is sculpted in weak spots
4.   Water seeps through rocks and makes underground
     waterways
5.   When the water level drops, the waterway exits the
     rock through the exiting hole (resurgence)
6.   Collections of water creates deep gaps in caves.
7.   When the water level outside the cave drops, the cave
     empties and dries out.
                       Stalactites
• Stalactites
   – Formed by water that drops
     from the top of the cave
     that contains calcite
   – The calcite is left when the
     water drops
   – Constant winds blowing
     cause stalactites to grow in
     crooked.
   – Occasionally, stalactites
     will grow together with the
     stalagmites and will create
     a column.
                 Stalagmites
• Stalagmites:
  – Form from the bottom
    of the cave
  – They grow about 1 cm
    every 1000 years
    because it is hard for
    water to evaporate in
    the moist cave
           Types of Stalactites
• Types of
Stalactites




• Icicle          Straw           Drape
       Types of Stalagmites




• Dish Stack       Fir Cone
Others
                 Cave Sections
• Cave environments fall into three basic categories:
1. Endogean: parts of cave that come into contact with
   the surface
   – Example: cracks, rock seams, groundwater seepage, and root
     protrusion
2. Parahypogean: regions near cave mouths that extend
   to the last penetration of sunlight.
3. Hypogean: deep in the cave, only come into contact
   with the surface through wind, underground rivers, or
   the migration of animals.
• Considered to be “true” cave environments
• The deeper the cave becomes, the less biodiversity is
   found.
             Types of Caves
•   Erosional- formed
    by the action of
    water or wind,
    carrying abrasive
    particles capable of
    carving rock
           Types of Caves
•   Lava Tube- lava travels beneath the
    surface and is expelled by a volcano
    during an eruption
             Types of Caves
•   Sea Caves- form
    from wave actions
    along the coast
    where areas are
    weak in sea cliffs
             Types of Caves
•   Solution Caves-
    form where rock is
    dissolved away
             Cave Organisms
• Cave organisms fall into three basic
  classes:
1. Troglobites: “cave dwellers” animals that are
   specialized for cave life.
  –   Can leave for short periods of time
  –   Can complete parts of their life cycles above ground
  –   Can’t live entire lives outside of the cave
  –   Examples: some bacteria, some flatworms, and
      blindfish
          Cave Organisms
2. Troglophiles: “cave lovers” can live
   part or all of their lives in caves
  – Can complete a life cycle in certain
    environments on the surface
  – Examples: cave crickets, millipedes,
    pseudoscorpions, and spiders
           Cave Organisms
3. Trogloxenes: “cave guests”
  – Frequents caves
  – May require caves for a portion of it’s life
    cycle
  – Must return to the surface
  – Examples: Hibernating reptiles and
    mammals
           Cave Organisms
•   Troglophobes: “cave haters”
•   Can’t survive in caves for any time period
•   Example: organisms that fall through
    sinkholes or frogs swept into caves by
    flash floods
    Adaptations of Things that Live in
                 Caves
• Loss of pigment
• Loss of eyes
• Blue eyes (can absorb light better)
• Elongation of appendages
• Enhancement of other senses (can sense
  vibrations in water)
• Echolocation
                    Bats
• Nocturnal
• They sleep in the back of caves to keep from
  being eaten
• Are found everywhere except Antarctica and the
  Artic
• Hibernate in caves
• When weather is warm, the bats leave the caves
  at night to find food
• They are the only mammals that can fly
• Wings are a membrane of skin that stretches
  from their body to their fingertips.
             Horse-shoe Bats
• Have horseshoe shaped
  structure around their
  nostrils to help direct
  sound for echo location
• They wrap their wings
  around themselves to
  keep warm during
  hibernation
• When they are asleep,
  they tuck their wings to
  their sides
Bat Communication and Pregnancy

• Pregnant bats move to a warmer area in
  the cave to give birth
• When the baby is young, it goes with the
  mother to get food
• When it is older, it is left behind and calls
  to the mother so she can find her way
  back
 Where do cave dwellers get food?
• Some get food from outside the cave
• Some eat things inside
  – Guano (Bat Poo) falls to the ground where millipedes,
    beetles, and fungi get their nourishment
  – Dead animals
  – Organic debris washes in from streams
  – Cave crayfish
  – Cave shrimp
  – Flatworms
             Cave Studies
• Speleology- the scientific study of caves.
• Spelunking- recreational exploring of
  caves.
• Cave cartography- creating cave maps
• Cave geology- study of cave rock.
• Cave Hydrology- study of water features
  in caves.
       Endangered Species
• Tooth cave spider
       Endangered Species
• Trapdoor spider
       Endangered Species
• Gray Bat

				
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posted:8/18/2012
language:English
pages:26