一、地球上的生命 二、生态学的形成与发展 三、生态学研究的目的

1、地面风场 年平均风玫瑰图(以佛山为例) 风向频率及其风速V

Chapter 1.a Fable for Tomorrow There was once a town in the heart of america where all life seemed to live in harmony with its surroundings The town lay in the midst of a checkerboard of prosperous farms, with fields of grains and hillsides of orchards where in spring white clouds of bloom drifted

Pests and pesticides Pest: ANY UNWANTED organism that directly or indirectly interfere human activity is called a pest. Pesticides, or biocides are substances that can kill organisms that we consider to be undesirable The most widely used types of pesticides Insecticides Herbicides

Acute(急性) and chronic(慢性) toxicity Acute toxicity refers to a rapid and serious response to a high but short-lived dose Acute poisons interfere with essential physiological processes, leading to a variety symptoms of distress, even death Chronic toxicity refers to a time-lagged response to a relatively low but prolonged exposure

Plant nutrients Plant growth requires various nutrients Major nutrient elements: C,N, P trace elements: S, Si, Cl, I, and metallic elements(Fe, Mn, Cu, etc) The minor elements because of the low demand can Water y be supplied at adequate rates in natural

Toxic metals Some metals are essential for the normal development and well-being of humans and other creatures They include Na, K, ca, Mg, cu, Cr, and Zn Other metals are toxic even when present in an organism at very low concentrations Examples: Antimony, Arsenic, Barium

General types of water pollutants Disease-causing agents(Pathogens) Oxygen-consuming agents Plant nutrients Toxic substances Heavy metals Pesticides Dissolved solids o acids

Objectives of Water Treatment The objectives for water treatment derive from two concerns Human health and welfare The health of aquatic ecosystems

pH of a buffer and buffer capacity Example: For a buffer solution consisting of 0. 1 M acetic acid and o1M sodium acetate the ph of the solution is 4.75 HAc= i If an amount of hydrochloric acid equivalent to 10% of the acetate present, is added to the buffer, what is the new pH of the solution?