Natural Selection in Action

Natural Selection in Action - NaturalSelectioninAction...

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Natural Selection in Action Higher Biology
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Natural Selection in Action Most mutations produce inferior versions of original gene Some mutations allow  adaption to a changing environment Mutant allele gives mutant form of organism a  selective advantage Change in environment -abiotic factor (e.g. pollution) -biotic factor (e.g. disease)
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Sickle cell anaemia Genetically transmitted disease of the blood Caused by presence of abnormal  haemoglobin S Abnormality occurs as result of mutation
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Haemoglobin S H – allele for normal haemoglobin S – allele for haemoglobin S People homozygous for mutant allele (SS) -sickle-shaped red blood cells -inefficient at carrying oxygen -cells clump together interfering with circulation
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Symptoms of Sickle Cell Anaemia Fatigue Breathlessness rapid heart rate delayed growth and puberty susceptibility to infections ulcers on the lower legs (in adolescents and adults) 
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This note was uploaded on 11/23/2011 for the course BIO 100 taught by Professor Robinson during the Fall '08 term at BYU.

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Natural Selection in Action - NaturalSelectioninAction...

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