Question

Which of the following is true of natural selection? Group of answer choices Natural selection works on traits acquired through an organism’s lifetime. Natural selection operates at the level of individuals. Natural selection operates at the level of populations.

Answer 1

Natural selection operates at the level of individuals, selecting organisms based on their heritable traits and overall evolutionary fitness, leading to adaptive evolution in populations.

Step-by-step explanation:

The statement that is true of natural selection is that it operates at the level of individuals. This means that while natural selection acts on the population's heritable traits, it actually selects for the survival and reproductive success of individual organisms. It evaluates not just one trait or allele in isolation, but the overall phenotype of the individual and its contribution to the gene pool of the next generation, known as its evolutionary (Darwinian) fitness. An important aspect to note is that natural selection cannot act on traits acquired during an organism’s lifetime, as it only affects heritable traits that can be passed on to offspring.

Natural selection leads to adaptive evolution, where beneficial alleles increase in frequency within a population due to environmental pressures facilitating better adaptation, survival, and reproductive success. The individuals that possess advantageous heritable traits are more likely to reproduce, therefore, these traits become more common over time among the population.

Answer 2

The correct answer is "Natural selection operates at the level of populations".

Step-by-step explanation:

One of the most common misunderstandings about natural selection, is that an individual can acquire new traits during its lifetime an "evolve" to survive challenging conditions. This is not true, because natural selection operates at the level of populations by the premise of "survival of the fittest". For instance, spontaneous and random mutations could make a bacteria resistant to an antibiotic from a population of bacteria that is not resistant. The only survivor of the population is the one that makes a bacteria resistant to an antibiotic.