DAT High Yield Biology Practice Test 2026 – The All-in-One Guide to Mastering Your Biology Exam!

A keystone species plays a critical role in maintaining the structure and functionality of an ecosystem, despite often being present in relatively low numbers compared to other species. The concept refers to the idea that these species have a disproportionate influence on their environment; their effects on the ecosystem can be substantial and often extend to many other organisms.

For example, if a keystone species were removed from an ecosystem, it could lead to significant changes, such as population explosions of certain species or the decline of others, ultimately disrupting the balance and health of the ecosystem. This is distinct from other species, which might have little to no effect if they were removed, thus reinforcing the importance of the keystone species in maintaining ecological stability. Such species could be predators, herbivores, or even plant species that provide essential support to various life forms, demonstrating how interconnected life within an ecosystem truly is.