Question

Which of the following μst exist in a population before natural selection can act upon that population? Select all that apply.

a) Genetic variation
b) High population density
c) Selective pressure
d) Differential reproduction

Answer 1

Natural selection in a population requires genetic variation, selective pressure, and differential reproduction. High population density is not necessary for natural selection. Selective forces including genetic drift, gene flow, and random mating additionally influence allele frequencies.

Step-by-step explanation:

Before natural selection can act upon a population, certain conditions must exist:

• Genetic variation within a population. Without genetic variation, there would be no differences in traits upon which natural selection could act.
• Selective pressure, which comes from environmental factors that make certain variations in the population more advantageous than others.
• Differential reproduction, meaning that individuals with advantageous traits are more likely to survive and reproduce, passing those traits on to the next generation.

High population density is not a requirement for natural selection, although it can influence the strength and speed of the selection process. Understanding how selective forces change the allele frequencies over time and how genetic drift, gene flow, and random mating can also influence these frequencies is key to comprehending evolutionary biology.