Question

1. why is natural selection a significant mechanism of evolution? 2. consider a specific gene with two different alleles (y and y). if there are 4 homozygous dominant and 3 homozygous recessive individuals, what is the frequency of the dominant and recessive alleles?

Explanation:

Step1: Define natural selection

Natural selection is the process by which organisms better adapted to their environment tend to survive and reproduce more offspring.

Step2: Explain significance in evolution

It leads to adaptation over time. Organisms with favorable traits for their environment are more likely to pass on those traits to the next - generation, driving changes in populations and the emergence of new species.

Step1: Calculate total number of alleles

Each individual has 2 alleles for a gene. There are \(4\) homozygous dominant (\(YY\)) and \(3\) homozygous recessive (\(yy\)) individuals. So the total number of individuals is \(4 + 3=7\), and the total number of alleles is \(2\times7 = 14\).

Step2: Calculate number of dominant alleles

Homozygous dominant individuals (\(YY\)) have 2 dominant alleles each. So the number of dominant alleles from homozygous dominant individuals is \(4\times2=8\). There are no heterozygous individuals given, so the frequency of the dominant allele (\(p\)) is \(\frac{8}{14}=\frac{4}{7}\approx0.57\).

Step3: Calculate number of recessive alleles

Homozygous recessive individuals (\(yy\)) have 2 recessive alleles each. So the number of recessive alleles from homozygous recessive individuals is \(3\times2 = 6\). The frequency of the recessive allele (\(q\)) is \(\frac{6}{14}=\frac{3}{7}\approx0.43\).

Answer:

Natural selection is significant in evolution because it leads to adaptation of populations over time by favoring the survival and reproduction of organisms with traits well - suited to their environment, which can drive speciation.