Tuesday, February 08, 2011

SEA TURTLE 1

The Chelonioidea has a world-wide distribution; sea turtles can be found in all oceans except for the polar regions. Some species travel between oceans.

Respiration

Sea turtles are almost always submerged in water, and, therefore, have developed an anaerobic system of respiration. Although all sea turtles breathe air, under dire circumstances they may divert to anaerobic respiration for long periods of time. When surfacing to breathe, a sea turtle can quickly refill its lungs with a single explosive exhalation and rapid inhalation. Their large lungs have adapted to permit rapid exchange of oxygen and to avoid trapping gases during deep dives. However, sea turtles must emerge while breeding, given the extra level of activity.

Life history

It takes decades for sea turtles to reach sexual maturity. After mating at sea, adult female sea turtles return to land to nest at night. In the extreme case, females return to the beach where they hatched. This can take place every two to four years in maturity. They make from one to eight nests per season..

The hatchling's gender depends on the sand temperature. Lighter sands maintain higher temperatures, which decreases incubation time and results in more female hatchlings.

Incubation takes about two months. The eggs in one nest hatch together over a very short period of time. When ready, hatchlings tear their shells apart with their snout and dig through the sand. Again, this usually takes place at night, when predators such as seagulls cannot fly. Once they reach the surface, they instinctively head towards the sea.

Salt gland

Sea turtles possess a salt excretory gland at the corner of the eye, in the nostrils, or in the tongue, depending on the species; chelonian salt glands are found in the corner of the eyes in leatherback sea turtles. Due to the iso-osmotic makeup of jellyfish and the other gelatinous prey upon which sea turtles subsist, sea turtle diets are high in salt.

NI2A/C
  • Homework: A set of exercises about linking words. Explanation of "another /other" as adjectives and pronouns.
  • Speaking: three students made their speeches and mistakes were checked.
  • Speaking: History quiz. St.B.p. 44. Historical events: the difference between history and story.
  • Phonetics. Silents letters.St.B.p.45. e.g.castle, fasten.
  • Reading: St.B.p.46. Read the passage about Henry VIII and insert the sentences on page 47. Check the vocabulary.
  • Listening: St.B.p. 47. Listen and complete the chart. Specific information.
  • Homework: Remember the composition for Wednesday, workbook p, 25,26,27,28.
NB1A/B
  • Homework: the exercises about adjectives
  • Speaking. what time is it? A review with the clock. Another activity. Pair work. Student A, page 108, student B, page 111. complete your clocks.
  • Listening: What time is it? Exercises, script, audio.
  • Vocabulary: Adjectives crosswords.
  • Vocabulary : St.B.p. 147. Daily routines. it was a review as we had already seen it. Match the drawing with the expressions. Test your partner.
  • Writing: write what do do everyday.
  • Speaking: In the meantime the students who hadn´t done the speaking test, had the chance to do it.
  • Listening: St.B.p. 30.Listen to vicky´s morning and write the seven times you hear.
  • Reading: St.B.p.30."How Stressed", Read and understand the passage
  • Listening: St.B.p. 31. Listen to Simon and answer the questions.
  • Homework: finish the exercises about adjectives and write a composition about your daily routines.