The frequency of an allele in an isolated population may change due to

According to the Darwin's theory of evolution, differences between the species occurs due to

The tendency of population to remain in genetic equilibrium may be disturbed by

 Definitions / Explanation: Gene Pool

In a species, the weight of newborn ranges from $2$ to $5\; \mathrm{kg} .97 \%$ of the newbom with an average weight between $3$ to $3.3\; \mathrm{kg}$ survive whereas $99 \%$ of the infants born with weights from $2$ to $2.5\; \mathrm{kg}$ or $4.5$ to $5 \;kg$ die. Which type of selection process is taking place?

A population is in Hardy- weinberg equilibrium for a gene with only two alleles. If the gene frequency of an allele $A$ is $0.7$, the genotype frequency of $Aa$ is