Ecosystem Interactions

Activities

Ecosystems are complex and profoundly interconnected systems. Abiotic (nonliving) factors, such as nutrients, soil, and climate, interact with biotic (living) factors, such as animals and plants. Because of the level of interconnectivity in ecosystems, a change in a single factor can have an effect on an entire ecosystem, including the level of biodiversity (a measure of the number of different kinds of organisms in an ecosystem).

As biodiversity decreases, so does the overall stability of an ecosystem. Humans can affect ecosystems and their stability by using land and other resources that could be used by other organisms. In addition, some human activities—such as the use of motor vehicles—release toxins into the ecosystem, which can damage both biotic and abiotic factors. All of these consequences of human activity can cause instability in an ecosystem, which can lead to decreased biodiversity and other harmful outcomes.

1. Animals or plants that give scientists clues about potentially undesirable changes in an ecosystem are called "indicator species." Please give an example of an indicator species.

Answer here: Spotted owl is an indicator of old growth habitat because spotted owl habitat was limited to the big, tall trees and standing dead wood found only in very old and mature forests.

2. Another example of an indicator species is the frog. Watch the video at the Malformed Frogs web site and read the related description of an experiment conducted by two students.

A. Describe how abiotic factors, biotic factors, and human intervention have affected the frogs in one pond.

Abiotic factors:

Answer here: To much UV light from the sun

Biotic factors:

Answer here: Parasites

Human Intervention:

Answer here: Chemical pollutants

3. In the experiment, the researchers found that parasites (a biotic factor) were the cause of the malformed frogs. They based this determination on their understanding of what types of...