6.2 Causes of VariationCauses of variationTwo main factors:1. Genetic factors 2. Environmental factors 1. Genetic factorsInfluenced by crossing-over, indeendent assortment, mutation and random fertilisationCrossing over, independent assortment and fertilisation.Genetic variation caused by mutation!utation " sudden ermanent c#ange in t#e nucleotide se$uence of t#e %&' or in t#e amount of %&'.Two tyes: 1. Gene mutation 2. (#romosome mutation!utation can cause by:1. (#emical or #ysical agents )mutagens*2. !ista+es t#at occur during %&' relication,. -neven distribution of t#e c#romosomes during cell division2. Environmental factors(aused by surrounding condition suc# as:1..ater2./unlig#t,.&utrients0.12.TemeratureT#e effect deends on #ow muc# condition received by an organism during growt#E.g. -(#inese rimrose )Primula sinensis* will roduce w#ite flower w#en grow in a warm temerature and will roduce red flower w#en grow in cool temerature. Environmentally induced cannot be assed to offsring but genetic variation can be in#erited /ome variation in c#aracteristics results from interaction between genetic and environmental factors E.g. t#e action of sunlig#t on genes for lig#ted-coloured s+in may result in dar+er s+in What are the importance of variation in the survival of a species?3rovides t#e necessary adatations for t#e secies to comete and survive. Essential for survival of t#e secies. Exercise Do Checpoint 6.2 on pa!e 2"2 in the te#tboo