How does stabilising, disruptive and direction selection contribute towards phenotypic variation observed in populations?

Imagine strong directional selection is applied, favoring large values of this trait. After one generation, what you predict would occur to the trait values in in each of the two different scenarios of 'h'?

Which of the following statements is CORRECT regarding models of adaptation that invoke allele-frequency adaptive landscapes? They assume that natural selection can either increase or decrease population mean fitness as long as there is no genetic dominance at any of the loci. They assume that natural selection can only increase population mean fitness, which means that populations can get "stuck" on local peaks associated with lower fitness than the global optimum. We can assume that such landscapes have multiple peaks only when there is no epistasis for fitness among any of the loci under consideration.

Which type of selection is represented in a population of birds where a wing span of 2ft rather than 1ft or 3ft is more beneficial?     Directional     Disruptive     Stabalizing

In a species of lily, the color of the flower's petals is determined by a dominant purple allele (F) or recessive white allele (f). One hundred flowers in Hardy-Weinberg equilibrium were sampled, and only 15% of the population showed the phenotype of white. Which of the following numbers represents the calculated value of the recessive white allele frequency? 0.92 0.39 0.15 0.85

> Within a certain population, there are exactly 2 alleles at the T locus: T and t. Among the entire population, 30% of the alleles are T. If this population is in Hardy Weinberg equilibrium, what proportions (or percentages, however, you want to express it) will be TT, Tt, and tt? Show work. In a population, there are 75 TT individuals, 25 Tt individuals, and 250 tt individuals. What are the frequencies of T and t? Show work. What are the "expected" numbers of each genotype? Show work. Ís this population in Hardy Weinberg equilibrium? (don't do Chi², just compare your answer in a) b) c) part b io actual and it should be obvious.) ) Assume that, in a population of deer, two alleles exist for eye color. BB deer have blue eyes, Bb deer have purple eyes, and bb deer have red eyes. Out of a population of 1000 deer, 490 have blue eyes. You took notes on the amount of red and purple eyed deer, but your notebook fell in the mud and those numbers are obscured. However, if the population is in…

Under which of the following scenarios would variation be maintained? Selection acting on a dominant high fitness allele Selection acting on a recessive high fitness allele Selection favoring heterozygotes Selection acting against heterozygotes None of the above

Why does the response to selection often level off after many generations of selection?