Answer:
0.78
Explanation:
Fitness measures the probability of survival and reproduction of a particular phenotype or genotype in a population.
Relative fitness measures how fit one genotype or phenotype is with respect to the most fit genotype or phenotype in a popualtion. It is calculated as = survival rate of that group / maximum survival rate observed in that population
Here,
Total number of yellow birds = 263
Yellows birds that survived = 150
Survival rate of yellow birds = 150/263 = 0.57
Total number of grey birds = 413
Grey birds that survived = 303
Survival rate of grey birds = 303/413 = 0.73
Grey birds have more survival rate than yellow birds so their survival rate is maximum in the population.
Fitness of yellow phenotype relative to grey phenotype = survival rate of yellow birds / survival rate of grey birds
= 0.57 / 0.73
= 0.78
Hence, fitness of the yellow phenotype relative to the grey one is 0.78.