I. Physical laws govern energy flow and chemical cycling A. Conservation of Energy 1. First Law of Thermodynamics (as it relates to ecosystems)

Transcription

1 CHAPTER 55: Ecosystems Overview: Observing Ecosystems A. Definition of an Ecosystem B. Two Basic Processes of Any Ecosystem 1. Energy Flow 2. Chemical Cycling I. Physical laws govern energy flow and chemical cycling A. Conservation of Energy 1. First Law of Thermodynamics (as it relates to ecosystems) Page 1 of 14 1

2 2. Second Law of Thermo as it relates to ecosystems B. Conservation of Mass 1. Describe how it relates to biological systems C. Energy, Mass, and Trophic Levels 1. Definition of a trophic level 2. Primary Producers 3. Heterotrophs a) Primary, Secondary and Tertiary Consumers Page 2 of 14 2

3 b) Decomposers: Prokaryotes and fungi II. Energy and other limiting factors control primary production in ecosystems A. Introduction 1. Primary Production (know its definition) B. Ecosystem Energy Budgets 1. Global Energy Budget 2. Gross and Net Primary Production (we either will do, have done or are in the process of doing a lab related to these terms so you best know this concept) Page 3 of 14 3

4 C. Primary Production in Aquatic Ecosystems 1. Light Limitation 2. Nutrient Limitation. a) The concept of the limiting nutrient b) Algal Blooms and nutrients c) Eutrophication (its definition) Page 4 of 14 4

5 D. Primary Production in Terrestrial Ecosystems III. Energy transfer between trophic levels is typically only 10% efficient A. Introduction 1. Secondary Production B. Production Efficiency 1. Introduction 2. Tropic Efficiency and Ecological Pyramids (know this well) Page 5 of 14 5

6 Tropic Efficiency and Ecological Pyramids (cont d) C. The Green World Hypothesis IV. Biological and geochemical processes cycle nutrients between organic and inorganic parts of an ecosystem. A. Biogeochemical Cycles 1. Definition (from the preceding paragraph) 2. General categories (just so you have the basic concept) Page 6 of 14 6

7 3. Figure is good for knowing the general concept. 4. The Water Cycle (Figure 55.14) Have a general idea of the 4 parameters of the water cycle, especially the Key Processes. This synthesis many of the topics we cover in individual chapters with Ecology. Page 7 of 14 7

8 5. The Carbon Cycle 6. The Terrestrial Nitrogen Cycle 7. The Phosphorus Cycle Page 8 of 14 8

9 B. Decomposition and Nutrient Cycling Rates 1. Factors controlling decomposition 2. Decomposition in a tropical rain forest, temperate forest, cold/wet environs and aquatic ecosystems. C. Case Study: Nutrient Cycling in the Hubbard Brook Experimental Forest 1. This is a nice quick read but no one will ask you specifically about the Hubbard Brook Experimental Forest study. Page 9 of 14 9

10 V. Human activities now dominate most chemical cycles on Earth A. Nutrient Enrichment 1. Introduction a) Human activity often removes nutrients from one part of the biosphere and adds them to another. b) Farms and nutrients 2. Agriculture and Nitrogen Cycling (as an example of how human activities affect chemical cycles) a) Loss of nutrients b) Nitrogen is the main nutrient lost through agriculture (i) How is it lost and regained? Page 10 of 14 10

11 3. Contamination of Aquatic Ecosystems a) The concept of Critical Load: the amount of an ADDED nutrient (like by humans) that can be taken in or absorbed by plants without damaging the ecosystem. By damage we mean taking over or overgrowth such as an algal bloom. B. Acid Precipitation (another way humans interfere with chemical cycles) 1. Sulfur and nitrogen oxides (SO 2, SO 3, NO 2 ) are all gases and they will dissolve in water to form sulfuric acid, sulfurous acid, nitrous acid and nitric acid and these are the components of acid rain (deposition) 2. Sources of the oxides 3. Examples of ph changes Page 11 of 14 11

12 C. Toxins in the Environment 1. The concept of Biological Magnification( very important and very easy to remember) 2. Examples Page 12 of 14 12

13 D. Greenhouse Gases and Global Warming 1. Rising Atmospheric CO 2 levels a) Source of CO 2 b) Consequences of rising CO 2 (i) Increased productivity of plants: C3 vs. C4 plants (this is good way of integrating info from 2 different chapters and the AP Committee loves to do this) 2. How Elevated CO 2 Levels Affect Forest Ecology: The FACTS-I Experiment a) No one will ask you about this specific experiment but you can gain some info from this to apply to essay questions. Page 13 of 14 13

14 3. The Greenhouse Effect and Climate a) Solar radiation is reflected from the Earth s surface back to space. On its way back to space it is trapped by CO 2, CH 4 (methane), water vapor. E. Depletion of Atmospheric Ozone 1. Ozone protects us from incoming UV radiation. 2. UV radiation damages DNA leading to skin cancer and cataracts. 3. What causes the breakdown of ozone into oxygen and oxygen atoms? Page 14 of 14 14