Reference no: EM131111660

Module Essay

Humans and Sustainability: An Overview

Compose a 300-word (minimum) essay on the topic below Essays must be double-spaced and use APA-style in-text citations to reference ideas or quotes that are not your own. You must include a separate bibliography

Relate each of the three scientific principles of suslainability to the Hubbard Brook Experimental Forest controlled experiment ("Core Case Study" at the beginning of Chapter 2)

Explain how each one of the results of the Experimental Forest experiments illustrates how human activities can have unintended harmful environmental consequences.

Give other examples of unintended consequences and harmful effects of human activities and explain.

You should cite and quote from assigned readings. AVP's, videos and module activities to support the ideas in your essay.

Case Study: Experimenting with a Forest

Suppose a logging company plans to cut down all of the trees on a hillside behind your house. You are very concerned and want to know about the possible harmful environmental effects of this action.

One way to learn about such effects is to conduct a controlled experiment, lust as environmental scientists do. They begin by identifying key variables, such as water loss and soil nutrient content, that might change after the trees are cut down. Then, they set up two groups. One is the experimental group, in which a chosen variable is changed in a known way. The other is the control group, in which the chosen variable is not changed. They then compare the results from the two groups.

In 1963, botanist F. Herbert Bormann, forest ecologist Gene Likens, and their colleagues began carrying out such a controlled experiment. Their goal was to cornpare the loss of water and sod nutrients from an area of uncut forest (the control Site) with one that had been stripped of its trees (the experimenter site)

They built V-shaped concrete darns across the creeks at the bottoms of sev¬eral forested valleys in the Hubbard Brook Experimental Forest in New Hampshire (Figure 2.1). The dams were designed so that all surface water leaving each forested valley had to flow across a dam, where scientists could measure its volume and dissolved nutrient content.

First, the researchers measured the amounts of water and dissolved soil nutri¬ents flowing from an undisturbed forested area in one of the valleys (the control site. Figure 2.1 left). These measurements showed that an undisturbed mature forest is very efficient at storing water and retain wig chemical nutrients in its solid.

Next, they set up an experimental forest area in a nearby vaBey (Figure 2.1. right). One winter, they cut down al the trees and shrubs in that valley, left them where they fell, and sprayed the area with herbicides to prevent the regrowth of vegatation

Then, for 3 years, they compared outflow of water and nutrients in NA experimental site with those an the control sate.

The scientists found that with no plants to help absorb and retain water, the amount of water flowing out of the deforested valley increased by 30-40%. As this excess water ran rapidly over the ground, it eroded soil and carried dissolved nutrients out of the topsoil in the deforested site. Overall, the loss of key soil nutrients from the experimental forest was 6-8 times that in the nearby uncut control forest.

In this chapter you will learn more about bow scientists study nature and about the matter and energy that make up the world within and around us. You will also learn about Byte scientific laws, or rules of nature, that govern the changes that matter and energy undergo. And you will learn the important difference between a scientific hypothesis and a scientific theory.