Trophic cascades are chain reactions in food webs. They happen when a change in one trophic level, such as predators, herbivores, plants, or tiny plankton, indirectly changes other levels. A predator can affect plants by changing how many herbivores are present or how those herbivores behave. A change in plant growth can also move upward … Read more
When predators disappear, ecosystems can change in ways that are much bigger than one missing animal. Prey animals may become more numerous, change where they feed, or spend less time watching for danger. Smaller predators may expand into new areas. Plants can face heavier browsing or grazing. Scavengers may lose some of the carcasses that … Read more
A keystone species is an organism whose role is unusually important to the structure of its ecosystem. The idea is not that the species is always the biggest, rarest, or most aggressive animal in a habitat. It is that the ecosystem can change in major ways when that species declines or disappears. Predator-based examples are … Read more
Food webs show how animals, plants, fungi, bacteria, and other living things are connected by feeding relationships. A food chain can make nature look like a straight line, but real ecosystems are usually more like a net: one animal may eat several foods, become food for several predators, and affect the habitat around it in … Read more
