If an ecosystem lost a keystone species, which outcome would be expected? The oxygen supply in the ecosystem would be depleted. The population numbers of other species would change dramatically. The temperature of the ecosystem would increase. A new keystone species would replace the old keystone species.

Correct question:

If an ecosystem lost a keystone species, which outcome would be expected?

A) The oxygen supply in the ecosystem would be depleted.

B) The population numbers of other species would change dramatically.

C) The temperature of the ecosystem would increase.

D) A new keystone species would replace the old keystone species.

B) The population numbers of other species would change dramatically.

Explanation:

There seems to be an ecological balance between all animals in nature. Some animals help to bring out the nutrients from the cycle while others help in decomposition, carbon, and nitrogen cycle. All animals, insects, and even micro organisms play a role in the ecosystem.

What is a keystone species? A keystone species is a species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system. A keystone species is often a dominant predator whose removal allows a prey population to explode and often decreases overall diversity.

Examples of keystone species include the bison and prairie dog

The population numbers of other species would change dramatically

Explanation:

When an organism exist in an ecosystem in such a way that it impacts  and influence in the ecosystem has a significant effect incomparable to its number in the  population,such organism is said to be a Keystone species.They are responsible for the structure and  continue existence of the  ecosystem. Thus their absence leads to change in the ecosystem structure.

They maintain ecosystem structure for example by suppressing   the population of  one species of organism. E.g if a keystone species is a predator, its continuous predation on the herbivores which graze over a particular land area maintain balance between the  green plant population and  nutrient cycles in the ecosystem. If the the Keystone does not exits over grazing from the increasing population of the grazers will disrupt the energy and nutrient cycles in the ecosystem, with dramatic change in the ecosytem.