APES CHAPTER 2

Deforestation effects

Roots hold riverbanks, stabilizing them and retaining soil nutrients like nitrogen and phosphorus

Sun exposure effect

More sunlight heats the environment, affecting plants and animals

Scientific theory

Rarely overturned unless new evidence discredits them

Scientific law

A well-tested, widely accepted description of phenomena repeatedly observed in nature

Matter

Consists of elements and compounds; has mass and takes up space

Element

Has unique properties; cannot be broken down chemically into other substances

Compound

Two or more elements bonded together

Law of conservation of matter

Matter is neither created nor destroyed in physical or chemical changes

Atomic theory

All elements are made of atoms

Proton

Subatomic particle with positive charge

Neutron

Subatomic particle with no charge (note: in APES notes it incorrectly says negative)

Electron

Negatively charged particle orbiting nucleus

Atomic number

Number of protons in an atom’s nucleus

Mass number

Number of protons plus neutrons in nucleus

Isotope

Atoms of the same element with different numbers of neutrons

Ion

Atom with net positive or negative charge due to loss or gain of electrons

Acidity

Measured with pH

Organic compound

Contains at least two carbon atoms

Types of organic compounds

Hydrocarbons, chlorinated hydrocarbons, simple carbohydrates, complex carbohydrates, proteins, nucleic acids, lipids

Cell

Fundamental unit of life; all organisms have one or more cells

Gene

Sequence of nucleotides in DNA; instructions for proteins; creates inheritable traits

Chromosome

Composed of many genes

Physical change

Change that does not alter chemical composition

Chemical change

Change that alters chemical composition

Nuclear change

Includes radioactive decay, nuclear fusion, nuclear fission

Chemical reaction

Making and breaking of chemical bonds between atoms

First law of thermodynamics

Energy cannot be created or destroyed in physical or chemical changes

Second law of thermodynamics

Energy conversion always results in lower-quality or less usable energy

Kinetic energy

Energy of movement

Heat

Form of kinetic energy; energy transferred between bodies

Electromagnetic radiation

Energy in waves (e.g., light)

Potential energy

Stored energy that can be converted to kinetic energy

Renewable energy

Obtained from resources replenished naturally in a short time

Nonrenewable energy

Resources that are depleted faster than they are naturally replenished

High-quality energy

Concentrated, has high capacity to do work (e.g., fossil fuels, high-temp heat, strong winds)

Low-quality energy

Dispersed, low capacity to do work

System

Set of components interacting in a regular way (e.g., human body, Earth, economy)

Feedback

Processes that increase or decrease changes in a system

Positive feedback loop

Amplifies changes in a system; can cause major environmental problems

Negative feedback loop

Counteracts changes; brings system toward stability

Time delay

Period between input of feedback and system response

Tipping point

Threshold causing fundamental shift in system behavior

Synergistic interaction

Two or more processes combine for a greater effect than individually

Law of conservation of energy

Energy is neither created nor destroyed; first law of thermodynamics

Entropy

Wasted energy lost in energy transfers; cannot be used by the system

Ecosystem

System of interdependent organisms and matter; matter is recycled, energy is not

Isotopes (C12 vs C14)

C12 has 6 protons, 6 neutrons; C14 has 6 protons, 8 neutrons

Radioactive decay

Breakdown of unstable isotopes releasing energy and particles

Albedo effect

Positive feedback loop where melting ice reduces reflectivity, accelerating warming

Sweating example

Negative feedback loop; heat triggers sweat, which cools body and stops sweating

Hubbard Brook Experiment

Clearing a mature forest degrades natural capital; demonstrates importance of sustainability

Three big ideas of matter and energy

1. You cannot throw anything away (conservation of matter) 2. You cannot get something for nothing (conservation of energy) 3. You cannot break even (second law of thermodynamics)

1st law of thermodynamics application

Energy cannot be created or destroyed; when energy is converted, the amount used equals the amount available

2nd law of thermodynamics application

Energy conversions always result in some energy becoming less usable; we cannot break even

Atomic mass

Approximate total mass of an atom, roughly equal to the sum of protons and neutrons

pH

A measure of the concentration of hydrogen ions (H+) in a solution; indicates acidity or basicity