Natural Selection in Action

Major objective of this lecture is to present on Natural Selection in Action. Most mutations produce inferior versions of original gene. Some mutations allow adaption to a changing environment and mutant allele gives mutant form of organism a selective advantage. Natural Selection change in environment – abiotic factor (e.g. pollution) and biotic factor (e.g. disease). Here also focus on Sickle cell anaemia: Genetically transmitted disease of the blood and caused by presence of abnormal haemoglobin S.