Review of Basic Science Concepts

Scientific Theories and Laws Are the Most Important Results of Science Scientific theory Widely tested Supported by extensive evidence Accepted by most scientists in a particular area Attempts to explain Scientific law Often mathematical in nature Attempts to describe Hypothesis A testable statement

The Scientific Method

Deductive Reasoning: Inductive Reasoning:

Independent and Dependent Variables

Example Do women have a smaller average shoe size than men?

Core Case Study: Carrying Out a Controlled Scientific Experiment F. Herbert Bormann, Gene Likens, et al.: Hubbard Brook Experimental Forest in NH (U.S.) Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site)

The Effects of Deforestation on the Loss of Water and Soil Nutrients

Figure 2.1 Controlled field experiment to measure the effects of deforestation on the loss of water and soil nutrients from a forest. V–notched dams were built into the impenetrable bedrock at the bottoms of several forested valleys (left) so that all water and nutrients flowing from each valley could be collected and measured for volume and mineral content. These measurements were recorded for the forested valley (left), which acted as the control site. Then all the trees in another valley (the experimental site) were cut (right) and the flows of water and soil nutrients from this experimental valley were measured for 3 years. Stepped Art Fig. 2-1, p. 28

Matter Consists of Elements and Compounds Has mass and takes up space Elements Unique properties Cannot be broken down chemically into other substances Compounds Two or more different elements bonded together in fixed proportions

Elements Important to the Study of Environmental Science

Atoms, Ions, and Molecules Are the Building Blocks of Matter (1) Atomic theory Subatomic particles Mass number Isotopes

Atoms, Ions, and Molecules Are the Building Blocks of Matter (2) pH

pH Scale Acids Bases pH of 7 is neutral pH <7 Examples: lemon juice, coffee, soda Bases pH >7 Examples: bleach, soap, baking soda pH of 7 is neutral Example: pure water

Loss of NO3− from a Deforested Watershed

Organic Compounds Are the Chemicals of Life Inorganic compounds

Organic Compounds Are the Chemicals of Life Hydrocarbons and chlorinated hydrocarbons Simple carbohydrates Macromolecules: complex organic molecules Complex carbohydrates Proteins Nucleic acids Lipids

Matter Comes to Life through Genes, Chromosomes, and Cells Cells: fundamental units of life Genes: sequences of nucleotides within the DNA Chromosomes: composed of many genes

Cells, Nuclei, Chromosomes, DNA, and Genes

Matter Occurs in Various Physical Forms Solid Liquid Gas

We Cannot Create or Destroy Matter Law of conservation of matter Matter consumption Matter is converted from one form to another

Energy Comes in Many Forms Kinetic energy Potential energy Stored energy

The Second Law of Thermodynamics in Living Systems

Energy Changes Are Governed by Two Scientific Laws First Law of Thermodynamics Second Law of Thermodynamics Energy efficiency or productivity

Systems Respond to Change through Feedback Loops Positive feedback loop Negative, or corrective, feedback loop

Positive Feedback Loop

Negative Feedback Loop

Time Delays Can Allow a System to Reach a Tipping Point Time delays vary Between the input of a feedback stimulus and the response to it Tipping point

System Effects Can Be Amplified through Synergy Synergistic interaction, synergy Helpful Harmful E.g., Smoking and inhaling asbestos particles

Human Activities Can Have Unintended Harmful Results Deforested areas turning to desert Coral reefs dying Glaciers melting Sea levels rising

Conversions 1 Hectare = 10,000 m^2 Metric Conversions: KHD (g/m/L) DCM

Conversions 1 Hectare = 10,000 m^2  1 km^2 = 1,000,000 m^2  Earth’s Land area = 150,000,000 km^2  Earth’s Water Area = 361,800,000 km^2  Earth’s Total Area = 511,800,000 km^2 Metric Conversions: KHD (g/m/L) DCM