Question

Usually, large secondary or tertiary consumers near the top of the food web, such as wolves, sea stars, sharks, and sea otters, are considered keystone species. Theses predators, control populations of herbivores, which, in the absence of predators, other types, could multiply and greatly change the plant community. However, other types if organisms also can exert strong community-wide effects. ""Ecosystem engineers' physically modify the environment shared by community members. Beavers build dams and turn streams into ponds that flood acres of dry land and turn them to swamp. Small organisms and those toward the bottoms of food web may have even greater impact. Remove the fungi that decompose dead matter or the insects that control plant growth, and a community may change very rapidly indeed.

Which of the following would make the best BEST title for this selection?
a) "Keystone Species in Yellowstone Park"
b) "Defining Trophic Levels"
c) "Surprising Keystone Species"
d) "Do Keystone Species Exist?"

Answer 1

A keystone species is important in an ecosystem as it controls the populations of other species. Ecosystem engineers physically modify the environment, and small organisms lower in the food web can also have a significant impact.

Step-by-step explanation:

A keystone species is one that plays an especially important role in its community, affecting the populations of many other species. They help control populations of herbivores, preventing them from multiplying and drastically changing the plant community. Keystone species are usually large secondary or tertiary consumers near the top of the food web, such as wolves, sea stars, sharks, and sea otters.

Ecosystem engineers are another type of organism that can have strong community-wide effects. These organisms physically modify the environment shared by community members. For example, beavers build dams that flood acres of dry land and turn them into swamps. Additionally, small organisms and those lower in the food web, such as fungi that decompose dead matter or insects that control plant growth, can also exert a significant impact on a community. Removing these organisms can lead to rapid and drastic changes in the ecosystem.