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Mabibi au mabwana (sex depends on temparature)


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I am working at KWS (Kenya Wildlife Service) in Malindi, as a volunteer of JICA. My job is teacher of environment. This presentation is about how creatures control sex ratio in nature. Also introduced new theory about how dinosaurs extinct related to control sex ratio. Also Introduced about some creatures adapted to cloning.

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Mabibi au mabwana (sex depends on temparature)

  1. 1. Mabibi? au Mabwana? Takatoshi AKAI KWS Malindi Marine Park JICA/JOCV231
  2. 2. Outline• Temperature decide sex in nature 1• Temperature decide sex in nature 2• How dinosaurs extinct?• The case of mammals• Male? Or Female?• Clone
  3. 3. Temperature decide sex in nature 1 In the full moon on the beach.
  4. 4. ① At full moon, the sea become high tide② Sea water can not reach higher than high tide, so eggs will not wash away
  5. 5. At first, when eggs lay,they are neither male nor female. The eggs hatch only when the temperature of sand between 26℃ ~ 34℃
  6. 6. • Therefore, because of global warming. The number of female turtles are increasing.
  7. 7. Temperature decide sex in nature 2
  8. 8. ①In reverse, crocodile lay eggs in many different places.②Also, temperature effected in reverse.Therefore, crocodile can control number of female and male!!
  9. 9. Case Study: Louisiana dismal② ③ ①
  10. 10. ①Beside the river (Dry & Warm)Beside the river,there are dried and warm enough.The temperature close to 34℃
  11. 11. ②Moisture swampMoisture swamp,there are humid and colder.The temperature close to 26℃
  12. 12. ③Water side in halfway point• In halfway point, humid a bit, not so warm, not so cold
  13. 13. How dinosaurs extinct?
  14. 14. Maybe… Huge Meteor Theory: Huge meteor hit the earth and extinctContinental drift theory:1 big continent “Pangaea”break up and connectedcontinuously.It lead volcano and shut sunlight.
  15. 15. New TheoryDinosaur is close to reptile, like crocodile.Because temperature changed to cold at that time, then all of their eggs became female.Then, species could not continue to raise their off springs.
  16. 16. No. of species
  17. 17. The case of mammals and birds • If X chromosome is only 1, who will become male. • If X chromosome is 2, who will become female
  18. 18. Male? Or Female?
  19. 19. Asexual reproduction = Clone• “Cnemidophorus”, kind of lizard habitat in South-west in US.• They are only female.• Reproduce own self, without sex.
  20. 20. • Aphidoidea also reproduce oneself by cloning without sex.Female clone herself inside of her and lay eggs.Male will born from cloned eggs,and sex with female to lay eggs.Those eggs will hatch in spring, but all ofthem are female.
  21. 21. In conclusion• Some reptile species depends on temperature to control their sex ratio.• Mammals depends on X chromosome to decide sex ratio.• Some species choose cloning to make offspring.• Some are use cloning and sex, depends on the season.