Final answer:
True, a genetically identical population of flowering plants can evolve through genetic drift and/or natural selection. Genetic drift can change gene frequencies over time, and even clonal plants can exhibit different phenotypes, creating a basis for selection. The Hardy-Weinberg principle helps identify evolutionary forces like selection impacting genetic structure.
Step-by-step explanation:
It is true that, even in a genetically identical (clonal) population of flowering plants where no mutations occur, the population can still evolve through genetic drift and/or natural selection. Genetic drift is a random process that can cause gene frequencies to change over time, particularly in small populations. Though the flowers are clones, they can still exhibit different phenotypes if epigenetics or environmental factors play a role, providing a basis for natural selection if those phenotypes have different survival or reproduction rates.
If bees cluster around red flowers more often than blue flowers and red is a recessive trait, the selection pressure could favor the red flowers, leading to a change in the population's genetic structure over time. The Hardy-Weinberg principle provides a baseline to compare with actual counts, helping researchers infer which evolutionary forces, including selection, might be influencing the population's genetic makeup.
Regarding the scenario where the flower population has been split by a river, differences in allele frequencies between the two new populations could indeed be caused by either genetic drift or natural selection. The small number of red flowers in population 1 suggests drift might have had a stronger effect there due to the small population size. In population 2, the higher relative number of red flowers could indicate that natural selection has favored the red allele, presumably due to the bees' preference.