Nguồn gốc của tất cả các thực phẩm năng lượng mặt trời đi vào. Điều này là vì các nhà máy có chất diệp lục Đó là Có thể kết hợp nước và carbon dioxide trong sự hiện diện của năng lượng ánh sáng và sản xuất đường. Điều này có thể được chuyển đổi đường đến nhà máy năng lượng là cần nó. | CHAPTER 4 Energy Flow in the Ecosystem The original source of all energy going into food is the sun. This is because plants that have chlorophyll are able to combine water and carbon dioxide in the presence of light energy and produce sugar. This sugar can be converted to energy as the plant needs it. Of course some of the sugar is converted into other complex chemicals that permit growth reproduction and other life INTRODUCTION The main concepts in this chapter concern how energy moves through an ecosystem. This is important in understanding how ecosystems are balanced how they may be affected by human activities and how pollutants will move through an ecosystem. FLOW OF ENERGY THE BASICS Simply defined energy is the ability or capacity to do work. For an ecosystem to exist it must have energy. All activities of living organisms involve work which is the expenditure of energy. This means the degradation of a higher state of energy to a lower state. The flow of energy through an ecosystem is governed by two laws the first and second laws of thermodynamics. The first law sometimes called the conservation law states that energy may not be created or destroyed. The second law states that no energy transformation is 100 efficient. That is in every energy transformation some energy is dissipated as heat. The term entropy is used as a measure of the nonavailability of energy to a system. Entropy increases with an increase in dissipation. Because of entropy input of energy in any system is higher than the output or work done thus the resultant efficiency is less than 100 . 48Tomera A. N. Understanding Basic Ecological Concepts. Portland ME J. Weston Walch Publisher p. 43 1989. 37 Copyright 2001 by Technomic Publishing Company Inc. 38 ENERGY FLOW IN THE ECOSYSTEM Odum explains that the interaction of energy and materials in the ecosystem is a primary concern of ecologists. 49 In Chapter 3 biogeochemical nutrient cycles were discussed. It is important .
