Introduction to APES Chapter 1-2 notes

HOW DO ECOLOGISTS LEARN ABOUT ECOSYSTEMS? Ecologist go into ecosystems to observe, but also use remote sensors on aircraft and satellites to collect data and analyze geographic data in large databases. – Geographic Information Systems – Remote Sensing Ecologists also use controlled indoor and outdoor chambers to study ecosystems

Geographic Information Systems (GIS) A GIS organizes, stores, and analyzes complex data collected over broad geographic areas. Allows the simultaneous overlay of many layers of data. Figure 3-33

Systems Analysis Ecologists develop mathematical and other models to simulate the behavior of ecosystems. Figure 3-34

Populations Grow Linear growth – Growth by a fixed amount Exponential growth – Growth by a percentage Like a bank account

J-Curves A special kind of exponential growth in which the % changes over time. The human population growth forms a “J” curve: *0.002% for most of human history *2.06% in 1970 *1.8% in 1980 *1.35% in 2000

Measuring Wealth GNP- measurement of economic growth Problem- doesn’t take into account the depletion of resources

GNP per capita- How we measure the wealth of a nation Problem- doesn’t tell how the wealth is distributed

Comparing Countries More Developed Countries US, Canada, Japan, Australia, New Zealand and Western Europe --20% of world population; have 85% of wealth --Use 88% of resources; make 75% of waste and pollution Less Developed Countries All other countries of the world --80% of world population; have 15% of wealth --use 12% of resources

Sustainability, is the ability of earth’s various systems to survive and adapt to environmental conditions indefinitely. The steps to sustainability must be supported by sound science. Figure 1-3 Sustainability: The Integrative Theme

Environmentally Sustainable Societies … meets basic needs of its people in a just and equitable manner without degrading the natural capital that supplies these resources. Figure 1-4

Resources Anything we use to obtain our needs --renewable or non renewable --recyclable or non recyclable

Resource Scarcity Resource scarcity – Absolute- insufficient or too costly to harvest – Relative- distribution is unbalanced i.e.: Oil not processed and shipped in large enough quantity to meet the needs of MDCs.

POLLUTION Found at high enough levels in the environment to cause harm to organisms. – Point source – Nonpoint source Figure 1-9

Pollution Some is caused by natural occurrences, most is caused by MDCs when developing or using certain resources. Effects of pollution – damage to plants – damage to health – disruption of life

World Views Whom should we believe? Controversy over how serious our environmental problems are.

World Views Planetary Management We are the most important species. We understand and control the earth. Technology will solve problems. All economic growth is good & potential is limitless. Environmental Wisdom Nature exists for all species. We are not in charge of the rest of nature. Some growth is environmentally beneficial, some is harmful. Resources are limited. Our success depends on learning to cooperate w/ each other and nature.

Aldo Leopold’s Environmental Ethics Individuals matter. … land is to be loved and respected is an extension of ethics. We abuse land because we regard it as a commodity… Figure 1-A

The 7 Steps of the Scientific Method Step Observe Question Hypothesis Test hypothesis Record results Form conclusions Report Example: I have a lot of clothes What should I wear? If I wear a sleeveless shirt, then I will be more comfortable. Wear a sleeveless shirt (In my mind) I am more comfortable. I accept my hypothesis To myself

Testing Hypotheses Scientists test hypotheses using controlled experiments and constructing mathematical models. – Variables or factors influence natural processes – Single-variable experiments involve a control and an experimental group. – Most environmental phenomena are multivariable and are hard to control in an experiment. Models are used to analyze interactions of variables.

Scientific Reasoning and Creativity Inductive reasoning – Involves using specific observations and measurements to arrive at a general conclusion or hypothesis. – Bottom-up reasoning going from specific to general. Deductive reasoning – Uses logic to arrive at a specific conclusion. – Top-down approach that goes from general to specific.

MODELS AND BEHAVIOR OF SYSTEMS Usefulness of models – Complex systems are predicted by developing a model of its inputs, throughputs (flows), and outputs of matter, energy and information. – Models are simplifications of “real-life”. – Models can be used to predict if-then scenarios.

THE NATURE OF ECOLOGY Ecology is a study of connections in nature. – How organisms interact with one another and with their nonliving environment. Figure 3-2

What Sustains Life on Earth? Solar energy, the cycling of matter, and gravity sustain the earth’s life. Figure 3-7

Ecology Eco- = interactions between organisms -ology = study Biosphere- where living things exist Living and non-living component -thin layer of soil, air and water 8 km deep into ocean and 8 km in atm Biome = geographical area defined by environmental conditions i.e.: desert, aquatic, grassland Ecology Terms

Ecosystem- unit of the biosphere where matter and energy are transferred as organisms interact with their living and nonliving environment. -Natural boundary- i.e.: pond, log in forest, forest as whole *Size depends on what is being discussed

Population- group of same species (able to mate and produce fertile offspring) Community- many species interacting Habitat- part of ecosystem where the animal lives niche- specific role the organism plays Ecology Terms

Homeostasis “Steady state”- leads to stability – in a living system – in an ecosystem “Steady state”- leads to stability -in a living system -in an ecosystem

3 Elements Control Homeostasis 1.receptor or sensor-detects condition 2.comparator- evaluates information 3.effectors- executes command – Coupled positive and negative feedback (like a thermostat)

3 Elements Control Homeostasis Negative feedback Ex: temperature rises, air cooler comes on temperature drops, air cooler goes off Positive feedback Ex: Increased body temperature, body sweats Continued rise in temperature overloads system until sweating can’t cool down, death from heat stroke

Feedback Loops: How Systems Respond to Change Outputs of matter, energy, or information fed back into a system can cause the system to do more or less of what it was doing. – Positive feedback loop causes a system to change further in the same direction (e.g. erosion) – Negative (corrective) feedback loop causes a system to change in the opposite direction (e.g. seeking shade from sun to reduce stress).

Feedback Loops: Negative feedback can take so long that a system reaches a threshold and changes. – Prolonged delays may prevent a negative feedback loop from occurring. Processes and feedbacks in a system can (synergistically) interact to amplify the results. – E.g. smoking exacerbates the effect of asbestos exposure on lung cancer.

Synergism The effect of 2 or more stimuli is more than the additive effect Ex 1: smoking & asbestos cause lung cancer When a person is exposed to both, he has 10X more chance of getting lung cancer than a simple additive effect. Ex 2: Chlorofluorocarbons destroy ozone & enhance the Greenhouse Effect More UVb rays enter atmosphere, killing phytoplankton so less CO 2 is absorbed by ocean Theory* Results in intense acceleration of global warming