Answer:
The correct answer is bottleneck effect.
Step-by-step explanation:
The phenomenon of bottleneck effect takes place when some natural events like a tsunami or an earthquake result in the destruction of the majority of the population and leave behind some to survive. Due to the bottleneck affect the genetic diversity within the population gets reduced drastically as the majority of the population gets perished, this results in the eradication of some of the genes from the population, while the left genes are passed onto the next progenies.
The bottleneck effect results in the generation of the new population as the leftover individuals further inbreed and give rise to a new population comprising the leftover genes. It is not necessary that the left genes passing on to the next generation are better than the one, which got eliminated, as the left genes have got selected by chance. Thus, it can be concluded that the given case is an illustration of the bottleneck effect.