Chapter 2 Flashcards
Environmental Systems: Matter, Energy, and Ecosystems
Watershed
area of land that drains into a body of water
Hypoxia
decomposition of phytoplankton depletes water
System
network of relationships that influence each other by exchanging energy, matter, information
Lithosphere
rock and sediment crust of the Earth
Atmosphere
air surrounding Earth
Hydrosphere
water
Biosphere
living organisms on Earth and nonliving components
Feedback loop
output is input back into the same system
Negative feedback loop
system in one direction causes movement in the opposite direction
Dynamic equilibrium
negative feedback systems that move in opposite directions at equivalent rates
Homeostasis
tendency of a system to maintain stable internal conditions
Positive feedback loop
output leads to increased input, stimulating another output (e.g. heat warms glaciers, causing melting, exposing more surface area to heat)
Runoff
precipitation that flows over land
Airshed
geographic area that produces pollutants that may land in a waterway
Matter
material with mass that occupies space
Chemistry
interactions of matter
Law of conservation of matter
matter can be transformed, not created/destroyed
Elements
substances with specific properties that cannot change, organized into the periodic table (e.g. uranium powers nuclear reactors)
Atoms
smallest unit with all an element’s chemical properties
Protons
positively charged, determine atomic number
Neutrons
no charge
Electrons
negative charge
Nucleus
dense center of an atom (protons and neutrons)
Isotope
element varies with neutrons
Radioactive
isotopes that change identity by emitting subatomic particles/radiation
Half-life
time an isotope takes to half-decay (700 million years for uranium-235)
Charged ion
atom gains/loses an electron (charge indicates how electrons are affected, e.g. Ca2+ lost two electrons, H+ lost one)
Molecules
combinations of two or more chemically bonded atoms
Compound
molecule made of multiple elements (e.g. Water, H2O and carbon dioxide, CO2)
Ionic bonds
ions of different charges attract/bind
Covalent bonds
electrons are shared between atoms without electric charges
Mixtures
atoms and molecules come together without reacting
Solution
even mixture
Neutral
equal concentrations of ions
Acidic
solution with higher concentration of hydrogen
Basic/alkaline
solution with higher concentration of hydroxide
pH scale
quantifies acidity/alkalinity of a solution, logarithmic
Water has a pH of 7 (H+ concentration of 10-7)
Acid has a pH below 7
Bases have a pH above 7
Organic compounds
compounds made of carbon atoms joined covalently
Hydrocarbons
organic compounds containing only hydrogen and carbon, like fossil fuels and petroleum products
Polymers
long chains of repeated molecules in organic compounds
Macromolecules
large molecules like polymers and lipids
Proteins
polymers made of amino acids, found in skin, hair, muscles, as enzymes that catalyze chemical reactions
Nucleic acids
deoxyribonucleic acid and ribonucleic acid, carry hereditary information, including blueprint for producing proteins; polymers made of nucleotides (molecules)
Genes
regions of DNA that encode for specific proteins
Carbohydrates
simple/complex sugars, such as glucose (blood sugar), cellulose (complex, found in leaves/bark/stems/roots), chitin (in insect exoskeletons)
Lipids
diverse group of molecules that don’t dissolve in water (fats, oils (store energy), waxes (structural), steroids (hormones))
Energy
ability to change position/composition/temperature of matter
Potential energy
energy of position
Kinetic energy
energy of motion
Chemical energy
potential energy stored in bonds of atoms
First Law of Thermodynamics
energy can change forms, but not be created or destroyed
Second Law of Thermodynamics
entropy
Autotrophs
organisms that use photosynthesis to transform molecules with low-energy bonds to sugar molecules with high-energy bonds using the Sun’s radiation
Photosynthesis
6CO2 + 6H2O + solar energy → C6H12O6 + 6O2
Chemosynthesis
deep-sea bacteria use chemical-bond energy from hydrogen sulfide (H2S) to turn inorganic carbon to organic carbon compounds
Cellular respiration
6CO2 + 6H2O + 3H2S → C6H12O6 + 3H2SO4
Heterotrophs
organisms that gain energy by feeding on other organisms
Ecosystem
all organisms/nonliving entities that interact in an area at one time (energy and matter cycle)
Estuary
ecosystem where rivers flow to the ocean, mixing salt and freshwater
Primary production
conversion of solar energy into chemical bonds in sugars
Gross primary production
total chemical energy from autotrophs
Net primary production
energy remaining after respiration is used to generate biomass
Secondary production
energy is used by consumers to generate biomass
Productivity
rate at which energy converts to biomass
Net primary productivity
energy/biomass remaining in an ecosystem after autotroph metabolizes enough for their own maintenance through cellular respiration
Ecotones
areas where adjacent ecosystems share resources/interact
Landscape ecology
scientists view systems of multiple ecosystems
Patches
areas of a habitat of an organism (spatial array)
Mosaic
patches are spread out over a landscape
Conservation biology
study of loss, protection, restoration of biodiversity
Geographic information systems
satellite imaging and computer software that layer sets of data on geology, hydrology, vegetation, animal species, human development, etc.
Model
simplified representation of complex natural processes
Ecological modeling
constructing/testing models to explain/predict ecological systems
Nutrient cycles/biogeochemical cycles
elements/molecules travel through the spheres in dynamic equilibrium
Reservoir
pool, like a person, cow, rocks, and the atmosphere
Residence time
time a nutrient spends in a reservoir
Source
reservoir releases more materials than it takes
Sink
reservoir accepts more materials than it releases
Flux
rate at which materials move between reservoirs
Hydrologic cycle
summarizes how water flows through the environment
Evaporation
convert water from liquid to gas, using heat, wind, exposure
Transpiration
release of water vapor by plants, leaving substances dissolved in water behind
Precipitation
rain/snow, which may be taken into plants, animals, or most commonly runoff
Groundwater
some precipitation sinks through soil/rock
Aquifers
regions of rock and soil that make underground reservoirs of water
Water table
upper limit of groundwater in an aquifer
Carbon cycle
describes carbon routes through the environment
Nitrogen cycle
nitrogen becomes biologically active and enters the biosphere/lithosphere
Nitrogen fixation
combine nitrogen with hydrogen to form ammonia (NH3), whose water-soluble ions of NH4+ (ammonium) can be taken by plants
Nitrogen-fixing bacteria
bacteria that convert nitrogen gas to ammonia
Nitrification
ammonium ions to nitrate ions NO2-, then NO3-, which plants take up
Denitrifying bacteria
convert nitrates back to nitrogen gas, releasing it back to the atmosphere
Bottleneck
step that limits flux of nitrogen out of the atmosphere (nitrogen fixation)
Phosphorus cycle
processes that move phosphorus from sinks to living matter
