Disturbing Nature's Balance
As the video from Page 1 showed, habitat loss affects the creatures that live there. This includes not only the wild animals but humans, too.
Factors that upset the balance of an ecosystem, such as habitat loss, are called disruptions. Disruptions can lead to population shifts. Population shifts are lasting changes in the numbers or kinds of animals that usually live in the ecosystem. The most severe effect of a disruption is the extinction of one or more species.
Certain disruptions are caused by specific natural events, such as forest fires, severe storms, and volcanic eruptions. Others are caused by more widespread changes, such as temperature or rainfall patterns. As you'll learn in this lesson, disruptions may also result from human activities. These include clearing land for farming or building, killing pests, and bringing species to a place they don't normally live.
In a food web model, arrows indicate feeding relationships. Food (energy) moves in the direction of the arrow. Most members of an ecosystem are connected to more than one organism.
Measuring Ecosystem Health
- Scientists measure an ecosystem's health by studying the species in it and the connections they share.
- Animals in an ecosystem depend on one another and the physical environment.
- The loss of any one species—whether it’s a predator or the prey it feeds on—can affect many others in the ecosystem. So can changes to the physical environment.
Before moving on, review key vocabulary used in the lesson using Match It.
