Unformatted text preview: a. geographical association between the distribution of polymorphic levels of these red blood cell anomalies and malaria b. clinical and experimental evidence suggesting that these red blood cell anomalies provide a lethal environment for the malarial parasite c. Balanced polymorphism for thalassemia explains the perpetuation of this red blood cell variant F. Conclusions 1. Natural selection is opportunistic. That is, selection acts only on the existing phenotypic/genotypic variation in a population. Therefore, there can be different roots of adaptation to the same environmental stress. (ex: malaria and three red blood cell variants- sickle cell, thalassemia, and G-6-PD deficiency. END OF TEST 1!!!...
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- Spring '07