Bio Help please! Hardy-Weinberg principle?

An example:  In a species of flowers, red petals (R) is dominant over white petals (r).  In a field of these flowers, there are 500 plants, of which 45 have white flowers.  What are the frequencies of the R and r alleles in this population and the distribution of the homozygotes and heterozygotes?

Well, the frequency of white flowers is 45/500 = 0.09 = frequency of rr.  The frequency of r is sqrt(0.09) = 0.3, which is called q.  Acording to H-W equation #1, the frequency of R = 1-0.3 = 0.7 which is represented by p.

Fr(RR) = p?2 = 0.49 or 49% are dominant homozygotes = 245 plants.
Fr(Rr) = 2pq = 0.42 or 42% are heterozygotes = 210 plants.
Fr(rr) = q?2 = 0.09 = or 9% are recessive homozygotes = 45 plants

You stated that you were not clear on what "it" is, therefore I am assuming what your not clear about is the Hardy-Weinberg principle. The Hardy-Weinberg principle is the idea that a certain allele's frequency is unchanging. The frequency of an allele is its presence in a population. Hardy-Weinberg requires several factors, the main of which are:
    all genotypes of the allele have equal fitness
    no mating preference exists for the allele
    no mutations occur
    and that the population observed is large
Now the important thing to remember is that Hardy-Weinberg principle only is concerned with the allele that is being focused on. I.E. if one were to say that blood type in a human population is in a Hardy-Weinberg state, then there exists no change in the frequency of that population, however other alleles frequencies may change such as hair color or skin tone.

Sexual selection or predation may be the easiest to perform in an experiment. For example you could perform a project using fish or some other animal that reproduces on a more frequent basis as examples stating that a specific phenotype is in Hardy-Weinberg. You could even go farther by having two populations, one with predatory fish and another without, and use the predatory fish to affect the population through predation and the population with predators to be affected by sexual selection. By revealing that in both populations over a couple of generations that the frequency is stable for the specific phenotype you can then state that Hardy-Weinberg exists for the specific phenotype and allele.  Obviously this would take an extended time period due to the need for a series of generations to show that the frequency remains stable. Thats my personal idea if you can think of an idea go for it and good luck.