def. system
is a network of relationships among components that interact with and influence one another through the exchange of energy, matter, or information.
2. Sometimes a system's output can serve as input to that same system, a circular process known as a ____________ ______.
feedback loop
What happens in a negative feedback loop?
output that results from a system moving in one direction acts as input that moves the system in the other direction
What happens in a positive feedback loop?
have the opposite effect. Rather than stabilizing a system, they drive it further toward an extreme.
How are the natural systems categorized by:
Scientists divide Earth's major components into structural spheres. : lithosphere, atmosphere, hydrosphere, biosphere
def. lithosphere
contains the rock and sediment beneath our feet, in the planet's uppermost layers.
def. atmosphere
composed of the air surrounding our planet.
def. hydrosphere
encompasses all water.
def. biosphere
consists of all the planet's living organisms and the abiotic (nonliving) portions of the environment with which they interact.
def. eutrophication
The process of nutrient overenrichment, blooms of algae, increased production of organic matter, and subsequent ecosystem degradation seen in the dead zones of the Bay
3. Increased nutrient pollution from farms, cities, and industries has led to the development of over ___ documented hypoxic dead zones globally as of 2008.
200
A. Atoms and elements are chemical _______ ______.
building blocks
All material in the universe that has mass and occupies space is termed _____.
matter
How does matter exist in the universe?
as a solid, liquid, or gas.
def. law of conservation of matter
Matter may be transformed from one type of substance into others, but it cannot be created or destroyed.
What are some examples of elements?
Hydrogen, nitrogen, phosphorus, and oxygen
def. element
a fundamental type of matter, a chemical substance with a given set of properties that cannot be broken down into substances with other properties.
def. nutrients
Elements needed in large quantities by organisms, such as carbon
Elements are composed of ______.
atoms
def. atoms
the smallest units that maintain the chemical properties of the element
An atom's _____ (positively charged particles) and ________ (particles lacking electrical charge) are in its nucleus. An atom's nucleus is surrounded by _____ (negatively charged particles).
protons;neutrons;electrons
def. protons
#NAME?
def. neutrons
particles lacking electrical charge
def. electrons
negatively charged particles
4. Atoms may also gain or lose electrons to become ____.
ions
def. ions
electrically charged atoms or combination of atoms.
1. Atoms bond together and form ________.
molecules
def. molecules
combinations of 2 or more atoms.
Scientists use a _________ _________ to indicate the type and number of atoms in the molecule.
chemical formula
def. compound
A molecule composed of atoms from two or more different elements
what is an example of a compound
carbon dioxide (one carbon atom bonded to two oxygen atoms) is an example of this.
Ions of differing charge bind with one another to form compounds with _____ _____.
ionic bonds
Atoms that lack an electrical charge combine by "sharing" electrons in _____ _____.
covalent bonds
Elements, molecules and compounds can come together in ______ without chemically bonding. Air in the atmosphere is a solution of many constituents, including nitrogen, oxygen, water vapor, ______, and _____.
solutions;methane;ozone
Hydrogen atoms determine _______.
acidity
Pure water contains equal numbers of hydrogen ions (H+) and hydroxide ions (OH-)�because of this, we say water is _____. Solutions in which H+ concentration are greater than OH- are ____. The reverse case creates solutions which are ____, or alkaline.
neutral;acidic;basic
The __scale quantifies the acidity or alkalinity.
pH
pH less than 7 indicates an ______ solution; pH greater than 7 indicates an _______ solution.
acidic;alkaline
Pure water has a pH of _.
7
The pH scale is __________; each step represents a tenfold difference in hydrogen ion concentration.
logarithmic
Matter is composed of :
organic and inorganic compounds.
______ compounds consist of carbon atoms joined by bonds, and they may include other elements. ______ compounds lack carbon-carbon bonds.
organic ; inorganic
One class of organic compounds that is important in environmental science is the __________ containing only atoms of carbon and hydrogen.
hydrocarbons
Macromolecules are building blocks of ____.
life
There are 3 types of polymers that are essential to life:
proteins, nucleic acids, carbohydrates
Def. polymers
long chains of repeated molecules
Along with lipids, these molecules are referred to as ___________ because of their large sizes.
macromolecules
def. protein
consist of long chains of organic molecules called amino acids. They serve many different functions in living cells including structural support, energy storage, immune system functions, hormones, and enzymes.
def. nucleic acids
direct the production of proteins. Deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) carry the hereditary information for organisms.
what are nucleic acids composed of?
nucleotides, each of which contains a sugar molecule, a phosphate group, and a nitrogenous base.
Regions of DNA that code for specific functions are called _____.
genes
def. carbohydrates
include simple sugars that are three to seven carbon atoms long. Among these is glucose which fuels living cells and serves as the base for complex carbohydrates.
def. Complex carbohydrates
include starch, an energy storage compound, chitin, a structural component of shells, and cellulose, the most abundant organic compound on earth which is found in the cell walls of plants.
def. lipid
are a chemically diverse group of compounds, classified together because they do not dissolve in water.
All living things are composed of ____, the most basic unit of organismal organization.
cells
_____ is always conserved, but it changes in quality.
energy
def. energy
is an intangible phenomenon that can change the position, physical composition, and temperature of matter.
def. potential energy
is the energy of position.
def. kinetic energy
is the energy of motion.
def. chemical energy
potential energy held in the bonds between atoms.
def. first law of thermodynamics
states that energy can change from one form to another, but cannot be created or lost.
def. second law of thermodynamics
states that energy tends to change from a more-ordered state to a less-ordered state, as long as no force counteracts this tendency. Systems tend to move toward increasing disorder, or entropy.
______ energy from the sun powers most living systems.
light
Some organisms use the sun's radiation to produce their own food. Such organisms are called _______ or producers and include green plants, algae, and cyanobacteria. Autotrophs turn light energy from the sun into chemical energy in the process called _____
autrotrophs; photosynthesis
When does photosynthesis occur?
within cell organelles called chloroplasts where the light-absorbing pigment chlorophyll uses solar energy to initiate a series of chemical reactions called light reactions.
what is the chemical equation of photosynthesis?
6CO2 + 6H2O + the sun's energy ? C6H1206 (sugar) + 6O2.
_______ depend on the sugars and oxygen from photosynthesis.
animals
_________ ________ releases chemical energy
cellular respiration
Organisms make use of the chemical energy created by photosynthesis in a process called ________ ____________.
cellular respiration
def. cellular respiration
Cells employ oxygen to convert glucose back into its original starting materials, water and carbon dioxide, and release energy to form chemical bonds or perform other tasks within cells.
What is the net equation for cellular respiration?
the exact opposite of that for photosynthesis: C6H12O6 (sugar) + 6O2 ? 6CO2 + 6H2O + energy
Respiration occurs in autotrophs and also in heterotrophs. What are heterotrophs?
organisms that gain their energy by feeding on the biomass of other organisms.
What does an ecosytem consist of?
all organisms and nonliving entities that occur and interact in a particular area.
Give an example of an ecosystem:
is the Chesapeake Bay estuary (a water body where rivers flow into the ocean, mixing fresh water with salt water).
def. ecosystem
are systems that receive inputs of energy, process and transform that energy while cycling matter internally, and produce a variety of outputs.
______ flows in one direction through ecosystems; it arrives mostly as radiation from the sun, powers the system, and exits in the form of heat. _____, in contrast, is generally recycled within ecosystems.
energy; matter
B. Energy is converted to _______.
biomass
As autotrophs convert solar energy to the energy of chemical bonds in sugars during photosynthesis, they perform ______ __________.The total amount of chemical energy produced by autotrophs is termed _____ _______ __________. The energy that remains after
primary production; gross primary production; net primary production
Ecosystems vary in the rate at which autotrophs convert energy to biomass. This rate is termed _________ and ecoysystems whose producers convert solar energy to biomass rapidly are said to have ___ net primary productivity.
;productivity; high net primary productivity
1. Ecosystems vary widely in size. Areas where ecosystems meet may consist of transitional zones called _______ in which elements of each ecosystem mix.
ecotones
def. landscrape ecology
scientists study how landscape structure affects the abundance, distribution, and interaction of organisms. These studies have been greatly aided by satellite imaging and geographic information systems (GIS).
3. A landscape is made up of ______ arranged spatially in a mosaic. Landscape ecology is of great interest to ____________ _________, scientists who study the loss, protection, and restoration of biodiversity.
patches; conservation biologists
def. model
is a simplified representation of a complicated natural process, designed to help us understand processes and make predictions.
def. ecological modeling
is the practice of constructing and testing models that aim to explain and predict how ecological systems function.
Earth's ecosystems provide goods and services that we could not survive without, called ecosystem services.
ecosystem services
Nutrients circulate in ________ cycles.
biogeochemical
nutrient cycles (or biogeochemical cycles)
circulate elements or molecules through the lithosphere, atmosphere, hydrosphere, and biosphere.
Nutrients move from one ___ or ________ to another, remaining for varying amounts of time in each. When a reservoir releases more materials than it accepts, it is called a _____, and when a reservoir accepts more materials than it releases, it is called a
pool or reseroir; source; sink; flux
The water cycle, or _______ cycle, is an integral part of nutrient cycling on Earth.
hydrologic cycle
Water moves from surface water and moist soil into the atmosphere by _________. Water also enters the atmosphere by ____________, the release of water vapor by plants through their leaves. Water returns from the atmosphere to Earth's surface as __________
evaporation; transpiration; precipitation; runoff
Some water soaks down through soil and rock through a process called ________ to recharge underground reservoirs known as aquifers. _______ are spongelike regions of rock and soil that hold groundwater, water found underground beneath layers of soil. The
infiltration; aquifers; groundwater;water table
______ _________ has affected nearly every flux, reservoir, and residence time in the water cycle.
human activity
The carbon cycle describes;
the routes that carbon atoms take through the environment.
What is an important function in the carbon cycle?
Earth's oceans
The largest human impact on the carbon cycle is through our use of ______ ______ as an energy source.
fossil fuels
Moreover when people burn forests and fields to clear land for agriculture, the carbon in wood and leaves is _______ to the atmosphere. Also, then, ___________ removes less carbon dioxide from the atmosphere than before.
released; photosynthesis
Sedimentary rocks are the largest reservoir in the _________ cycle.
phosphorous
What increases phosphorous concentration ?
human activities in surface water through substantial runoff of the phosphorus-rich fertilizers we apply to lawns and farmlands.
The nitrogen cycle involves specialized bacteria.
______ is an essential ingredient in the proteins, DNA, and RNA that build our bodies, and is an essential nutrient for plant growth. Thus, the nitrogen cycle is of vital importance to us and to all other
nitrogen
To become biologically available:
inert nitrogen gas must be "fixed," or combined with hydrogen in nature to form ammonia, whose water-soluble ions of ammonium can be taken up by plants.
Nitrogen fixation can be accomplished in 2 ways:
by the intense energy of lightning strikes, or by particular types of nitrogen fixing bacteria that inhabit the top layer of soil.
def. nitrification
, converting ammonium ions first into nitrite ions, then into nitrate ions.
Animals obtain the nitrogen that they need by _______ plants or other animals. ________ obtain nitrogen from dead and decaying plant and animal matter, and from the urine and feces of animals.
consuming; decomposers
The next step in the nitrogen cycle occurs when _______ bacteria convert nitrates in soil or water to gaseous nitrogen.
denitrifying
_______ _________ to the nitrogen cycle have had profound impacts beyond the eutrophication of aquatic ecosystems. Tackling nitrogen enrichment requires diverse approaches.
human alterations