Within a gene pool, there will be alleles that result in beaks that are well adapted to the available food and beaks that are not well adapted. How are the alleles in the gene pool of the bird population affected by which birds survive?

According to the given case, one type of beak is well adapted to the available food and other is not. Birds with better beaks will be more successful in feeding hence will be healthy and live long. Whereas birds with the inferior beaks will face challenge while feeding and survival for them will become difficult. So, number of birds with better beaks will increase in population whereas number of birds with inferior beaks will decrease. As a result, frequency of the better allele will increase in gene pool. Eventually, it will surpass the inferior allele.

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.

the electromagnetic energy from the sun arrives in the form of visible and invisible light.