bvw v w
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On voit ici la paroi cellulaire, le cytoplasme périphérique et des organites de grande taille : les chloroplastes. Dans certains d’entre eux, on distingue une structure granulaire vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvgfvjhkjhcsqngrqngnytkj,t,h,sfnhgjhk,dhshdjhgjyhkjuklilkfukyjkyrkyrjnrjyrjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj- jjjjjjjjjj LA TRANSITION DEMOGRAPHIQUEDéfinition
Évolution caractérisée par une baisse de la mortalité et de la natalité.
Pendant la transition, la natalité est cependant plus importante que la mortalité, la population augmente donc beaucoup et très vite.
Lors de la pré-transition la croissance du taux de mortalité (trait noir) ainsi que le taux de natalité (trait rouge) et quasiment nul.
Phase 1 : Le taux de natalité reste le même pendant pratiquement toute la durée de cette phase. Il est toujours aussi élevé. La chute commence tout à la fin de cette étape. En ce qui concerne le taux de mortalité (surtout infantile), on observe la chute immédiate dès le début de cette phase. Elle est en chute constante. Cette baisse est du au développement de pays ainsi que « l'amélioration des conditions sanitaires ».
Phase 2 : Le taux de natalité commence à baisser et décroît à une extrêmement grande vitesse grâce aux changement de mentalité un peu due à la médecine (les femmes font moins d'enfants car ils peuvent être soignés).
On remarque que le taux de mortalité se stabilise et cesse de décroître. (grâce à la médecine qui se perfectionne et qui permet de soigner en particulier les enfants)