Soru

Passage A
In ecological theory, the concept of a "keystone species" describes an organism that helps define an entire ecosystem. Without its keystone species, the ecosystem would be dramatically different or cease to exist altogether. A classic mechanism by which keystone species maintain ecological balance is through a "top-down trophic cascade." In this model, a top predator controls the population of its primary prey. By keeping the prey population in check, the predator indirectly protects the plants or organisms that the prey consumes. Consequently, the removal of the keystone predator leads to an overpopulation of the prey, which can subsequently decimate the foundational flora of the ecosystem, leading to a loss of overall biodiversity and habitat collapse.

Passage B
For decades, the coastal kelp forests of the Pacific Ocean faced mysterious and rapid declines, often being reduced to barren underwater landscapes known as "urchin barrens." Biologists eventually identified the root cause of this ecological shift: the historical overhunting of sea otters. Sea otters are the primary predators of sea urchins, which are voracious consumers of kelp. When sea otter populations were healthy, they consumed enough urchins to prevent the urchins from overgrazing the kelp. However, as fur traders decimated the otter populations in the nineteenth century, the unchecked urchin populations exploded. The urchins rapidly consumed the holdfasts of the kelp, leading to the destruction of the kelp forests and the collapse of the diverse marine community that relied on the kelp for shelter and sustenance.

Which of the following best describes the relationship between Passage A and Passage B?