The Chinese Alligator ( Alligator sinensis; above) is a critically endangered sp
ID: 311544 • Letter: T
Question
The Chinese Alligator (Alligator sinensis; above) is a critically endangered species living in a restricted reserve area in the Yangtze River in China’s Anhui province. (Captive populations are doing much better; where individuals may live up to 70 years).
(3 pts) After spraying an insecticide the number of individuals of each genotype that survived is given below. Calculate the absolute fitness, and relative fitness of each genotype. Round up the answers to three decimal points.
Genotype
Number of individuals survived
AA
50
Aa
18
aa
15
Genotype
Number of individuals survived
AA
50
Aa
18
aa
15
Explanation / Answer
From the given data,
Assuming that the population size is 500, the number of alleles is = 1000
The frequency of A = frequency of AA + 1/2 frequency of Aa = 50/83 + 1/2 (18/83) = 0.71
The frequency of a = frequency of aa + 1/2 frequency of Aa = 15/83 + 1/2 (18/83) = 0.288
The expected frequencies are,
AA = 0.71*0.71 = 0.5041; number of alleles is = 0.504*1000 = 504
Aa = 0.71* 0.288 = 0.204; number of alleles is = 0.204*1000 = 204
aa = 0.288*0.288 = 0.082; number of alleles is = 0.288*1000 = 288
The absolute fitness is,
AA: 50/504 = 0.099
Aa: 18/204 = 0.088
aa: 15/288 = 0.052
The relative fitness is,
AA: 0.099/0.099 = 1
Aa: 0.088/0.099 = 0.88
aa: 0.052/0.099 = 0.525