Question

Determine whether each scenario describes macroevolution or microevolution: Suppose some individuals in a population of diploid bellflowers with two sets of chromosomes undergo abnormal meiosis that causes a doubling of chromosomes and yields tetraploid offspring with four sets of chromosomes. The phenomenon causes instant reproductive isolation between the diploid bellflowers and tetraploid bellflowers. This scenario represents what kind of evolution?

1) Macroevolution
2) Microevolution

Answer 1

This reproductive isolation is a major evolutionary change that separates the two populations and could potentially lead to the evolution of two distinct species over time.

Final answer:

The bellflower scenario with chromosome doubling leading to tetraploid offspring represents macroevolution, as it causes speciation through reproductive isolation and long-term evolutionary changes.

Step-by-step explanation:

The scenario described indicates macroevolution because it leads to speciation, the formation of a new species. This occurs through the process called polyploidy, an error in meiosis causing a chromosome doubling and creating tetraploid offspring. These tetraploid offspring are reproductively isolated from the diploid parental population due to their difference in chromosome number.

Over time, this reproductive isolation can result in divergent evolution, where the tetraploid population evolves independently from the diploid population, eventually becoming a distinct species. This process fits into the larger pattern of macroevolutionary changes that occur over long periods of geological time.