Env. Science Exam 1

Hypothesis

possible and testable explanation of the data

Theory

well-tested and widely accepted scientific hypothesis or a group of related hypotheses that is accepted as being a useful explanation of some phenomenon by most scientists in a particular field

Scientific Law

well-tested and widely accepted description of observations that always happen in the same way in nature that cannot be broken except by discovering new data that leads to changes in the law

Scientific Method involves…

• making careful observations

• asking questions

• researching what is already known

• developing hypotheses

• designing experiments to test projections

• analyzing the results

• communicating the results

3 steps in scientific critical thinking

1. be skeptical about what you read or hear

2. evaluate evidence and hypotheses from a variety of reliable sources

3. identify and evaluate your personal assumptions, biases, and beliefs- be sure to distinguish facts from opinions

Matter is made up of...

Atoms

Ions

Molecules

Together, Atoms, Ions and Molecules make up...

Elements (all the same atoms)

Compounds (combinations of multiple atoms)

Atoms

the smallest building block of matter that an element can have that will still retain its chemical properties

An atom's 3 subatomic particles

protons- positive electric charge

electrons- negative electric charge

neutrons- no electric charge

Atomic number

the number of protons in an atom's nucleus

Mass number

the total number of neutrons and protons in an atom's nucleus

Isotopes

variants of an element that have the same atomic number, but a different mass number

Molecules

two or more atoms of either the same or different elements held together by chemical bonds (electrical attraction)

Ions

an atom or group of atoms with one or more net positive or negative charges

Acidity

the comparative concentration of hydrogen ions (H+) and hydroxide ions (OH-) in a substance measured with the pH scale

Subscripts following letters in a chemical formula indicate...

the number of atoms

What does organic mean?

Organic compounds have carbon atoms bonded to various other elements

Hydrocarbons

contain carbon and hydrogen atoms

Simple carbohydrates contain...

carbon, hydrogen, and oxygen

Polymers are...

simple organic compounds (monomers) chemically bonded together

3 major types of polymers

Complex carbohydrates: contain two or more monomers of simple sugars such as glucose (cellulose, starch)

Proteins: are polymers formed by amino acid monomers

Nucleic acids: are polymers formed by nucleotide monomers (DNA, RNA)

What is the DNA structure?

Composed of helical strands of nucleotides. Each nucleotide contains a phosphate (P), a sugar, S (deoxyribose), and one of four bases (A, G, C, T)

Physical changes are...

changes in size or state (ice to water), do not involve changes in chemical composition

Chemical reactions are...

changes in chemical composition of the substances involved- shown through using chemical equations

First law of thermodynamics

No energy is created or destroyed when energy is converted from one form to another

Second law of thermodynamics

Physical and chemical changes in which energy is converted from one form to another results in lower-quality or less-usable energy

Energy is...

the ability to do work or to transfer heat

Kinetic Energy is...

associated with motion (wind, flowing water) and includes heat or thermal energy- temp. is a measure of the total kinetic energy of a sample of matter, and electromagnetic energy- energy travels as waves due to changes in electric/magnetic fields

Potential Energy is...

stored and potentially available for use (water stored behind a dam) potential energy can be changed to kinetic energy

Qualities of Energy

High-quality: aka concentrated energy, has a high capacity to do useful work

Low-quality: aka dispersed energy, has little capacity to do useful work

Efficiency: ratio of useful energy output to total energy input

System:

a set of components that function/interact in a regular way, with three components:

- inputs

- throughputs or flows

-outputs of both matter and energy

Feedback

any process that increases (positive feedback) or decreases (negative feedback) a change to a system

Feedback loops

Occur when the output of matter or energy is fed back into the system as an input that leads to changes in that system

Biomimicry

a growing movement to understand, mimic and catalog the ingenious ways nature has sustained life

Sustainability

The ability of ecosystems and human cultural systems to survive, flourish, and adapt together to constantly changing environments over long periods of time

Ecosystem

a group of organisms (biotic) in a defined geographic area that interact with each other and their environment (abiotic)

3 Scientific principles of sustainability

dependence on solar energy

biodiversity (provides ecosystem services and adaptability)

chemical/nutrient cycling

Natural capital comprises

natural resources (which can be inexhaustible, renewable, or nonrenewable) and ecosystem services (which are provided by healthy ecosystems

Humans degrade natural capital by...

using resources faster than nature can restore them & degrading natural resources with pollution and waste

MEDC stands for...

More Economically Developed Countries (like United States, Western Europe, Australia, Japan)

LEDC stans for...

Less Economically Developed Countries (Sierra Leone, Bangladesh, Afghanistan, Haiti)

Environmental degradation:

over time growth of ecological footprints depletes and degrades earth's natural capital (natural resources and ecosystem services)

sustainable yield is...

the amount that can be extracted without exceeding the growth over time

Ecological footprint is...

the amount of land and water needed to supply a population or geographic area with resources

Biocapacity is...

the ability of an area's ecosystem to regenerate resources used & absorb wastes generated by an area's population in a given time period

Ecological Deficit equation

if ecological footprint > biological capacity then = living unsustainably

What does IPAT stand for?

Impact (I) = Population (P) x Affluence (A) x Technology (T)

Affluence = consumption/population (Gross Domestic Product per person)

Technology = impact/consumption (sum resources used / GDP)

What 3 major cultural changes impacted humans' ecological footprint?

1. Agricultural Revolution (humans started farming & domesticating animals) 10,000 years ago

2. Industrial-Medical Revolution (mass industrialization leads to urbanization which leads to pollution) 250 years ago

3. Information-Globalization Revolution (world-wide phenomenon, transporting people/goods globally) 80's/90's to present

What is the rule of 70?

a simply way to calculate how long it takes for a population to double based on the growth rate doubling time (yrs) = 70/annual growth rate (%)