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# Ecosystem

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Source:
Author: Janice VanCleave

### Interactions

In nature, there is a constant interaction among animals, plants, fungi, protists—microorganisms not easily classified as fungi, plant or animal—and their environment. A specific area where living and nonliving things interact is called an ecosystem. In this ecosystem, there is a direct relationship between the community of living organisms and its surroundings. The organisms affect their physical surroundings just as they are affected by them.

In this project you will observe some of these interactions in an open ecosystem and investigate populations within a sector. You will also determine populations of organisms by using the technique of random sampling.

### Getting Started

Purpose: To select and lay out a study area.

### Materials

• compass
• measuring tape
• hammer
• 12 wooden or metal tent stakes
• 300 yards (300 m) of cord

### Procedure

1. Select a study area that has a variety of plant life. (A wooded area was chosen by the author, but any ecosystem can be used.)
2. Use the compass to determine which direction is north.
3. With the measuring tape, measure an area 30 × 30 yards (30 × 30 m). The plot of ground should be laid out so that it is aligned in a north-to-south direction.
4. At each of the four corners of the plot, hammer one stake into the ground, leaving about 6 inches (15 cm) of the stake aboveground.
5. Attach the end of the cord to one stake, loop it around the other stakes, and tie it to the starting stake to enclose the plot.
6. Use the measuring tape to divide the sides of the plot into 10-yard (10-m) sections.
7. Drive one stake into the ground at each 10-yard (10-m) interval along all sides of the plot (see Figure 22.1).
8. Using cord to join opposite stakes, divide the plot into nine equal subplots.

### Results

A sampling plot of ground is selected, measured, and subdivided.

### Why?

An environment is all the external factors affecting an organism. These factors may be biotic factors (living organisms) or abiotic factors (nonliving things including water, soil, climate, light, and air). All organisms living in a particular environment, such as a forest or desert, together with the abiotic factors that affect them, are collectively known as an ecosystem. In an ecosystem, energy and nutrients flow between the abiotic and biotic environment.

A sampling plot is a select area of an ecosystem that allows you to study the biotic and abiotic factors in it. During a field study, measurements of physical factors and organisms are taken. Separate information taken from each subplot, when studied as a whole, provides a clear picture of the abiotic and biotic factors within the plot and gives clues to the greater ecosystem surrounding the plot.

### Try New Approaches

On graph paper, sketch the plot. Identify each subplot with a number. Indicate the compass directions on the sketch with arrows. Make separate sketches of each subplot. Note prominent land features such as trails, open areas, erosion, and streams.

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