Transcript story - MarineBioSpring2010

Adaptations for land and sea.
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Sea turtles are and endangered
group with only seven species
known to still exist. Of the
seven species, six – green sea
turtle, Hawksbill, Kemp’s
Ridley, Olive Ridley, flatback,
and Loggerhead have hard
shells that sea turtles are known
for. Only the leatherback turtle
has a system of bony plates and
leathery skin.
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Though they spend much of their
lives under the water, all sea turtles
need to breathe air. Sea turtles
have a very slow metabolism
which allows them to stay
submerged for extended periods of
time.
The lungs of sea turtles are able to
rapidly expel and take in oxygen
when surfaced, which adds to the
length of time that can be spent
beneath the surface.
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Sea turtles can be found in every ocean of the
world except for the Arctic, the reptile’s cold
blood making it a good idea to stay away from
the icy temperatures of polar waters.
Sea turtles can play an important role in their
native ecosystems. Sea turtles are one of the
few types of animals that eat sea grass,
allowing it to remain a healthy nurturing
environment for many types of fish and other
marine life.
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Sea turtles also play an
important role in
maintaining the existence of
some beaches and sand
dunes.
The thousands of sea turtle
eggs laid on many beaches
each year that do not hatch
provide a great source of
nutrients for the continued
life of many beach plants.
These plants in turn help
prevent further erosion from
taking place on the beaches.
The dark blue areas are where sea turtles have been naturally found. As you can
see, the native habitat of the sea turtles stretches like a band around the center of
the earth.
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Since they are reptiles, all sea turtles have a
bone in the middle ear that carries vibrations to
the middle ear, allowing them to respond to
sounds with a low frequency.
Sea turtles see very well under the water, but
have limited vision while on land.
The soft areas of the flippers and shell allow
sea turtles an awareness of their surroundings.
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While not much is
known about the sea
turtles sense of taste
or smell, scientists
believe that while
under the water sea
turtles have a very
strong sense of smell.
This ability allows
them to find food
even in murky waters.
Adaptations of the
Sea Turtle
As a marine animal, the sea
turtle developed a salt
gland to allow the body to
rid itself of excess salt. Not
only do sea turtles spend
their entire lives swimming
in waters with high salinity
levels, much of the food
that they eat is also
extremely salty.
The salt gland empties out
through the sea turtle’s
eyes, making it look as
though the turtle is crying
when it surfaces or walks
on land.
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When female turtles return to the beach to lay
eggs, the salty tears excreted by the salt gland
help keep sand out of the expectant mother’s
eyes while walking or digging a hole to lay
eggs in. This type of adaptation ties the sea
turtle to not only its marine ecosystem, but also
serves a helpful purpose on land.
Sea turtles have adapted to become expert
swimmers and divers. Forearms evolved into
the large paddle-shaped flippers that sea
turtles are known for, giving them a great deal
of surface area to push with on every stroke.
THE NECK AND LIMBS
OF THE SEA TURTLE ARE
NON-RETRACTABLE.
RETRACTABLE LIMBS
WOULD DIMINISH THE
EXCELLENT SWIMMING
ABILITY OF THE SEA
TURTLE
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The body of the sea turtle has also adapted
itself for the many deep dives that it makes.
Though they need oxygen to breathe, some sea
turtles can remain under the water for a half
hour or more.
To conserve oxygen in the body during long
periods of submersion, some sea turtles may
slow their heart-rates to astounding levels.
Others have body systems that redirect blood
from areas that can handle low-oxygen levels
to important areas such as the heart and brain.
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It is adaptations such
as these that show
how sea turtles have
evolved to live and
flourish in their
natural habitats.
Being great swimmers
and divers allows the
sea turtles to find food
more easily or escape
from ocean predators.
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http://www.seaworld.org/animal-info/infobooks/sea-turtle/adaptations.htm
http://en.wikipedia.org/wiki/Sea_turtle
http://www.sharkysdive.net/sea_turtles_fact_
sheet.htm
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The story can be used as an introduction to marine
life, or, with the many examples given, a lesson
could be done concerning adaptation and
evolutionary processes, explaining why
modifications take place and how they benefit the
animals in their natural environments.
As a PowerPoint presentation, the story can be
presented to the class as a whole, or used by
individuals or groups of students working on
computers. Class discussion can be done with one
group leading the rest of the class through the
lesson.
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Communicating Scientific Information:
1. Develop explanations that explicitly link
data from investigations conducted, selected
readings and, when appropriate, contributions
from historical discoveries.
Participate in group discussions on scientific
topics by restating or summarizing accurately
what others have said, asking for clarification
or elaboration, and expressing alternative
positions.
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Evolution:
Explain that in any particular environment, the
growth and survival of organisms and species
depend on the physical conditions.
Explain that in any particular environment
individual organisms with certain traits are
more likely than others to survive and have
offspring.