Adaptations for land and sea. The Life of Sea Turtles Adaptations for land and sea.

Natural History of the Sea Turtle 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.

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.

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.

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.

Habitat Zones of the Sea Turtle 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.

Sensory System 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.

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.

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.

Sea Turtle vs. Land Turtle The neck and limbs of the sea turtle are non-retractable. Retractable limbs would diminish the excellent swimming ability of the sea turtle

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.

Finding a Niche 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.

Resources http://www.seaworld.org/animal-info/info-books/sea-turtle/adaptations.htm http://en.wikipedia.org/wiki/Sea_turtle http://www.sharkysdive.net/sea_turtles_fact_sheet.htm

Teacher’s Notes 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.

Maryland State Learning Standards 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.

Maryland State Learning Standards Cont. 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.