Students in a genetics laboratory began an experiment in an attempt to increase heat tolerance in two strains of Drosophila melanogaster. One strain was trapped from the wild six weeks before the experiment was to begin; the other was obtained from a Drosophila repository at a university laboratory. In which strain would you expect to see the most rapid and extensive response to heat-tolerance selection, and why?

Video transcript

Hi everybody. Let's take a look at this practice problem together, the phenotype pick variants for body length in fish in a pond population is 54.2 and the Jena typical variance for the same is 15.4, determine the environmental variance for this trait. So recall that phenotype is the observable characteristics of a trait. Therefore, phenotype IQ variance is going to be the variety of phenotype sis that can be observed in a population also recall that phenotype is determined by genetic and environmental factors. Therefore, the equation for phenotype IQ variants will look like this and you should recall this formula here we have the phenotype Ipic variance equals the gina typical variants plus the environmental variance. Well, we're given both the phenotype variance and the gina typical variants. Therefore we can solve for the environmental. So let's plug in the numbers. We are told, phenotype variance is 54.2 equals and the Jena typical variance is 15.4. So plus the environmental variants, solving for environmental variants, we have 54.2 -15. equals 38.8. Therefore, our answer is B- 38.8. Alright, everybody, I hope you found this helpful and I'll see you soon for the next practice problem