About relative frequencies...?

Question

I really don't understand how sexual reproduction does not change relative frequencies. By having offspring, the number of those particular alleles are increased in the gene pool, right...? Could someone fill me in... (please explain thoroughly and clearly)

If relative frequency IS actually the number, then it still doesn't make sense, even after I read the explanation.

Answer 1

If we assume that inheritance patterns are random (no selection for a particular allele), then yes, sexual reproduction does not change the relative frequencies of a particular allele.

Let's think of it this way: if an organism "Aa" and "Aa" mate, we can use a punnet square to determine the possible genotypes of the offspring. They are "AA", "Aa", "Aa", and "aa." You will notice that the allele frequency of A and a remain unchanged from the parent to the offspring generation. 50% A and 50% a.

Let's think of it this way. Parent's have a certain frequency of alleles. The frequency of a given allele is equal to the probability of that allele getting passed down to the next generation. That probability must equal the frequency of the allele in the next generation.

If it helps, think of it as pulling apples and oranges out of a bag. If the bag is 50% oranges and 50% apples, the probability that I pull out an apple is 50%. If I keep pulling out apples and oranges, (and for this model, my magic bag will always be 50% apple and 50% orange), the fruit that I pull out will be 50% apple and 50% orange. Pulling out fruit like this is akin to sexual reproduction.

Oh, the number of a particular allele will be higher, but the frequency will not be (assuming no selection, and a large population.)

I hope this makes sense!

Answer 2

this question is deceptive. If the question asked with reference to the factors plotted on the ogive graph and not the factors labelled on the dimensions of the x-axis, then the respond is obvious. a factor is plotted alongside the top classification cut back. case in point, if the cumulative frequency (alongside with the class in question) is 32 and the top cut back of the class is 15, the co-ordinates of the factor are x (the variable)=15 and y (cumulative frequency)=32. that's plausible that the question has perplexed the plotted factors with the labels on horizontal axis. because of the fact the x-axis is non-quit, you're unfastened to choose on a life like scale and labelling. To make plotting the graph much less annoying, you would be able to settle directly to label the x-axis scale so as that the labels correspond to the factors. case in point, if the top limits are 5, 10, 15, 20 etc. that's clever to label the horizontal axis 5, 10, 15, 20 . . . yet there is not any rule approximately this. right this is a quote from an information superhighway e book on Histograms, that explains that classification barriers are in many cases chosen, for simplicity, so as that they coincide with handy scale divisions on the horizontal axis (and the communicate): "via choosing communities beginning at one million mile and with a width of one million mile, the barriers of the communities and the x-axis divisions coincide. This makes introductory examples of the histogram much less annoying to understand and is often the case in GCSE Maths questions. in maximum circumstances, besides the shown fact that, there is not any requirement for the barriers to line up with the dimensions divisions." Taking all this into consideration, the respond that's in all risk predicted is "a" - the factors labelled are the top classification limits.