Flashcard maker : Lily Taylor
people who study the size, density, and distribution of human population
Pre-agricultural period
coincided with the development of human culture
-skills made humans adopt to new environment
Agricultural period
domestication of plants and animals and the developing of farming
more food, increase in population
Industrial period
technologies powered by fossil fuels increased food production
-agriculture expanded onto land where it was previously unfit for farming
Stage 1: Demographics Transition Models
Human population is limited by low availability of food and high prevalence of diseases
-death rate is high
Stage 2: Transition models
mortality transitions
improved economic conditions
death rate decreases and birth rate stays high
Stage 3: mortality models
fertility transitions;
lower birth rates
use contraceptives
death rate is low and lower birth rate
Stage 4: Democratic models
stability transitions
low birth rate and low death rate
birth and death rate are almost equal
Age-specific birth rates
tells the number of children born in a year per 1000 women within defined age group
Infant mortality rate
percentage of infants within a population who die before age 1
what is infant mortality rate influenced by
water quality and sanitation
life expectancy
average age to which a baby born at a given time will live, provides a summary of differences in survivorship
Age structure pyramids
illustrate graphically how populations are apportioned according to age and gender
what forecasts future growth rates
age structure pyramid
net migration rate
difference between immigration and emigration per 1000 individuals in the population
Push factors of migration
conditions that force people to emigrate; war, epidemics, famine, drought
Pull factors of migration
conditions that encourage people to immigrate into a country; employment, educations, high living standards
Stage 1: Before Economic Transitions
Birth rate: High
Death rate: High
Reasons for Stage 1
-low food availability
– high prevalence of diseases
– high death rate among young
-zero to low population growth
Stage 2: mortality transitions
Birth rate: high/ possibly increasing
Death Rate: decreasing
Reasons for stage 2
?improved economic conditions
?better living conditions and health care
?expanded access to education
Stage 3: fertility transition
birth rate: decreasing
death rate: low
Reasons for stage 3
?Continued economic developments
?People delay starting families (lower total fertility rates)
?People limit the number of children
stage 4: stability transition
birth rate: low
death rate: low
Reasons for stage 4
BR nearly equal to DR
zero population growth and decline
Immigration (pull factors)
moving in
-freedom, education, employment
Emigration (push factors)
moving out
-war, famine, oppression, persecution
Net migration rate; when is it high
difference between immigration and emigration
emigration is highest when there is a war
Ecological footprint
area of land needed to supply resources consumed
area and quality of land to supply resources
population exceeds biocapacity when…
ecosystem’s good are imported
IPAT equation
Impact, population, affluence, technology
what is IPAT
conceptual model of human impact
capacity to do work
cannot be created nor destroyed
force applied to an object over some distance
Newton’s laws of motion
any object at rest will stay at rest, and any object in motion will remain in motion unless acted upon by some force
Potential energy
energy that is stored in a system and available to do work in the future
Kinetic energy
energy in motion
When you hold a book (what kind of energy)
What happens when a book is falling
kinetic energy
What happens when a book hits the floor
energy is shattered and heat is transferred
First law of thermodynamics
total amount of energy in the universe is constant
What is the first law if thermodynamics called
law of energy conservation
What is the second law of thermodynamics
states that every energy transformed increases disorder
describes the disorder or disorganization in the system
what happens in every energy transformation
the same amount of energy is converted to entropy
lease usable form of energy is that random motion of molecules
what does heat have a high amount of
forms of energy that are important for ecosystems
electromagnetic radiation
electromagnetic radiation
energy acts as both particles and waves
electromagnetic spectrum
entire range of wavelength
gamma rays, X rays, ultraviolet, visible light, infrared, microwaves, radio waves
distance between corresponding points on adjacent waves
number of waves passing a given point per unit of time
frequency of unit cycle per seconds
speed of light
electromagnetic radiation travels at the same speed of light
What happens when there are shorter wavelengths
energy will be higher because frequency is higher
measure of the average kinetic energy of a collection of molecules
heat can move by
conduction, radiation, convection, latent heat transfer
molecules ramming into other molecules and transferring heat
since heat has to do with molecules and it hits up with something that has less energy, it will transfer the energy making the molecules move faster
waves of heat
heat being transferred through heat waves
most often it is infrared
Water that is hot is less dense then cold water; if the water is less dense then it starts moving up because it wants to float on the water that is more dense
Denser material wanting to move down and warmer wanting to move up
Heat is transferred because hot molecules are moving up causing movement of the water
Latent heat transfer
There is actual molecules moving
As water starts to move, it causes gas;they have the most energy and begin to break away
As things evaporate;the things that leave take the most energy
Examples: when we sweat; it is taking energy away and is a mechanism to keep our body cool
What kind of energy is chemical energy
What is chemical energy
the breaking and forming of chemical bonds
When do you use energy
to break bonds
when do you give off energy
when you form bonds
Photosynthesis assembles…
carbohydrates (glucose)
What do glucose bonds use
potential energy
When needed, energy is released by …
Nuclear energy
energy in the structure of matter (usually matter)
Nuclear fission
nucleus of atom splits, creating two smaller atoms and releasing vast amounts of kinetic and electromagnetic energy
Nuclear fusion
when atoms collide and fuse
2 atoms become one
process that powers the sun and all the stars
what gives off the energy from the sun
What is energy measured in
energy to support 1kg mass
energy to raise 1 g of water 1 degree C
amount of electricity for an hour at 1 joule per hour
What holds the earths atmosphere
Atmospheric pressure
air at surface compressed by gases above
Pressure _____ as altitude _______
decreases; increases
lowest layer
life located here
temperature drops with elevation
11-48 km
temperature increases approaching ozone
ozone later located here
what is the ozone layer
located in stratosphere
protects life from ultraviolet radiation
ozone is pretty toxic to us
What is in the atmosphere
Saturation vapor pressure:
Temperature dependent
amount of water air can hold rises with temperature
as you get warmer, the air can hold more water
When does rain and fog occur
above saturation vapor pressure water condenses
Relative humidity
extent air is saturated with water
expressed as percentage
air cant hold as much water in the winter as it does in the summer
Dew point
temperature where humidity is 100%
What happens when there is dew
water becomes saturated
What happens when temperature goes up
relative humidity goes down
when does air hold more
when its hotter
Energy budget
measures all energy entering and leaving Earth
Balances over time
Solar radiation percent
30% reflected to space
70% absorbed by land and water
how much of radiation that comes from sun is visible light
How much has shorter wave lengths and for the most part ultraviolet radiation
How much has longer wave length and is infrared
The solar energy that comes
-6% never comes because its reflected off
-20% is reflected into the clouds
-4% is reflected from the earth’s surface
-3% is absorbed by clouds
-16% is absorbed by atmosphere
-5% is absorbed by land and oceans
From the energy that comes….
7% is conducted back into space or convection
-23% is carried to clouds and atmosphere by latent heat in water vapor
-64% is radiated to space from clouds and atmosphere
-15% is radiation absorbed by atmosphere
when sunlight interacts with water…..
it causes molecules to move faster and rotate and vibrate more and then absorb energy and given off as infrared radiation
what is infrared radiation
what if the atmosphere was only nitrogen and oxygen
then the infrared would go back into space because it does not interact with infrared radiation
what does the atmosphere contain
water and carbon dioxide
what are the green house gages
carbon dioxide and water
what do greenhouse gases do
warm the earth
Is greenhouse affect the same thing as global warming
explain greenhouse gases
water molecules send of radiation in every direction, some goes back back into the space while some goes into earth; some interact with other molecules and therefore it radiates into other directions….it is trapping it in the atmosphere making the earth warmer
greenhouse is warmed because of…
the roof and traps the heat
most abundant greenhouses gas in the atmosphere is…
water vappor
why do we not worry about water vapor
the water forms clouds therefore some of the radiation from the sun gets reflected back out from the clouds
water helps to reflected
-the amount of water in the atmosphere depends on the temperature
Explain water and rain
air has a limit that the water can hold. if it exceeds that limit then it rains
-long term atmospheric conditions
-years or decades
-closer to equator the warmer and rainier it is
-temperature, humidity and average rainfall
Short-term variations local atmospheric conditions
-thunderstorms, snow
Wind cells
sunlight unequally heats Earth
is getting a lot of energy and can hold a lot of water in the air
Warmer things
are less dense
As the equator…
heats up and causes the wind cells to rise up and cause rain and then pushes the less dense air which causes the air to sink causing it to sink because it doesn’t have that much water in it
Difference causes
differing temperature and pressures
Air circulates in
large convection currents; climates are affected
when you move toward the poles
you get less sun per area
Earth is tilted on its
axis 23.5 degrees
More direct sunlight means
that there is no more sunlight you get per area which means more energy
When you have the atmosphere…
you have to go through less atmosphere so you get less energy causing it to be warmer in the summer
The only affect off seasons is…
how directly the sun is to the place not the actual locations
the tilted earth causes what?
differential heating throughout the year
what does it mean when you have more direct heating in the summer
higher density of photons reaching Earth, less atmosphere through which photons pass
differential heating causes
higher temperature
Coriolis effect
earth is spinning causing the atmosphere to spin with it; equator is travelling faster therefore the wind is travelling faster
Earth is curved and the surface is…..
not moving as fast as the equator causing wind to occur
Global warming potential causes
change in climate
what is very important to the global warming
current concentration and residence time
tiny concentrations have
a huge impact
concentration in the summer begins to…..
decrease because there is more photosynthesis and plant growth in the summer than in the winter
Carbon dioxide…in the winter because…
increases; there is less growth in the winter
Global warming gases
nitrous oxide
carbon dioxide
Increase in carbon dioxide occurs because…
we burn fossil fuels, deforestation, agriculture
Fossil fuels cause an increase in what
nitrous oxide
Deforestation causes carbon dioxide to increase how
cut down trees that take trees that take carbon dioxide from the air
how does agriculture affect the increase in methane
cows, pigs, animals because of machines and cutting down forests for more land
Consequences of global warming
Climate pattern changing(drier and wetter); melting glaciers and ice sheets(80% Earths glacier retreating); rising sea levels, changing populations and ecosystems(climate key to ecosystems)
How do you forecast global warming
predicating the future (computer simulation)
Global circulation models (forecast climate change; accuracy checked by back casting (using past record))
why do we bother forecasting global warming
to gage how much an effect we have now
yellow line
shows us our lower limit (today’s world-you know what we are doing)
red line
kind of tells us our upper limit (business as usual; an assumption)
blue line
people and government take sustainable actions to control co2 emissions
CAFE standards
maximum of fuel efficiency for cars
The protection against selfish actions, why don’t individuals have a big effect
because there is already so much in the air
How much will switching to cleaner fossil fuels do
take us down one wedge
Pro of cleaner fossil fuels
pollute less
con of cleaner fossil fuels
gets more expensive and we use what we use now because its cheap and per gallon it has a lot of energy
Renewable energy
wind solar biofuels
wind; wedge potential
eliminate 1 billion tons (very small)
Solar; wedge
one wedge
biofuels; wedge
one wedge
con for biofuels
what are we using to make biofules,,corn and that uses a lot of land for it
cons of wind
comes from windmills; only generate energy when its windy; storage issue; and kill birds
nuclear energy(need more land because)
you have a place to dispose the waste and produces a lot of radioactive waves; there can be a nuclear power accident
Bio storage
storing carbon in forests(plant trees) and in the Earth (through soil)
downside of bio storage in forests
takes a lot of time for them to grow and you take more land to plant the forests and you take away land for farmers and developing countries
committed warming=
inevitable change
what happens because of global warming
earth still warming no matter what
drier climate and drought
increase rainfall and flooding
increasing heat
patters of storms
rising sea levels
regional differences
drier climate and drought effects…
water supply and agriculture
increased rainfall and flooding effects…
agriculture and infrastructure
increasing heat effects….
crop losses and fires
patterns of storms effects….
coastal areas at risk
(strengthening levees and restoring coastal wetlands)
rising sea levels effects…
coastal and low lying areas flooded
salt intrusion of groundwater
regional differences effects..
capacity to adapt not evenly distributed
electric energy
energy of flowing charged particles (electrons through a wire)
Electric current is measured in
amperes (amps)
electrical resistance is measured in
ohms (?)
Electric potential is measured in
one volt is the ….
difference of potential needed to drive one ampere of current against one ohm of resistance
electric power measured in
kilowatt hours
unit of energy equal to power multiplied by time
electric generation
we just burn it and it generates heat which produces steam then it turns a turbine
if you use wind or water power then you
start at the turbine
turbine then does what
turns the conducting material in the generator then you get electric power flowing through the electric current which goes into the forms of wire
coal is using…
chemical energy which is turning into mechanical energy because it is making things move then turning into electric energy
reduce amperage and increase voltage to facilitate transmission(then do reverse at the end)
Multiple power plants do what
feed the power grid
Electric power grid
network of transmission lines and transformers
Base load
minimum amount of electricity for consumer needs
peak load
maximum amount of electricity consumers demand
-will occur on a hot day in Florida in the summer (using air conditioning)
smart grids
-instantly communicate usage to power company
-allow for adjustable pricing
-electricity is more expensive during peak hours and less expensive during off hours
-will provide energy savings
Lead-Acid batteries
-you will find them in cars
-all have anode and cathode
-gives you the energy to get your car started
oxidation occurs; metal gives off electron
reduction occurs; takes in electrons
alkaline batteries
non rechargeable
everyday batteries
electrolyte is potassium hydroxide
nickel cadmium batteries
you can recharge them by adding energy
-you can plug in and recharge them
lithium ion batteries
cellphones, electronics
very light
in electric cars because they are light and take up less space
battery power
when you get more density you become lighter
heaviest battery
lead acid
lightest and gives off most power battery
what do batteries have that hydrogen fuels cells dont
all the fuels stored in the battery so that you dont have to carry around that energy
hydrogen fuel cells
add to the reaction instead of carrying it all around
-you are not giving of carbon dioxide
oil, coal and natural gas
replaced biomass as our dominant sources of energy
global consumption is..
at its highest level ever
fossil fuels have
much higher density energy
what are the reasons for higher density energy
larger population and huge spike in technology
what makes fossil fuels efficient to burn, ship and store
high energy content of fossil fuels
secondary form of energy that is easy to transfer and apply to a convert of uses
it takes energy to
make energy
what requires substantial inputs of energy
to harness, extract and process and deliver energy
net energy
difference between energy returned and energy invested
(energy returned-energy invested)
EROI meaning
Energy returned on investment
(energy returned/energy invested0
what does higher ration of EROI mean
we receive more energy than we take in
EROI rises when
technology improves
EROI declines when
we extract the easier deposits first
hydro power has a high EROI because
we dont need to put in a lot of effort to do it
things that are more renewable have
lower EROIS
how and when were fossil fuels formed
organisms that lived 100-500 million years ago
where do fossil fuel chemical energy come from
originally from the sun and converted by photosynthesis
what are the 2 forms of decomposition
aerobic and anerobic
aerobic decomposition
occurs in the presence of air; organixc material is broken down in simpler molecules and recycled through the ecosystem and it doesnt produce coal, gas or oil
anaerobic decomposition
occurs with little or no air; in deep lakes, swamps and seas; produces fossil fuels
what is coal
hard blackish substance formed from organic matter compressed under very high pressure to form dense, solid carbon structure
what is the most abundant fossil fuel
coal varies from
deposit to deposit in water and carbon
carbon is formed from
plants hundred of millions of years ago
coal seams
deposited in layers of sediment
organic material that is broken down anaerobically
-wet, near surface, and not well compressed
types of coal
coal with most pressure
extraction and processing of coal
removed from sediments by underground and surfacing mining
(cleaned to remove dirt and other impurities)
what is coal transformed into
electricity at coal-fired power plants
what is coal mining
strip mining destroys large swaths of habitat and causes extensive ersion
Acid drainage
process through which chemical runoff from strip mining enters waterways
what does mountain top removal do
removes tons of rock and soil, destroying immense amounts of habitat and creeks
what do emissions do
cause severe health problems
what is released into the environment
burning coal high in mercury
what variety of pollutants does coal emit
sulfur, mercury
coal is converted into cleaner synthesis gas by reaction with oxygen and stem
where do fossil fuels of each type occur
isolated deposits
what methods are oil sands extracted
collected sands are mixed with hot water to separate out the bitumen and deeper oil sands are extracted by drilling shafts into them and injecting steam
oil or gas must be
processed after extraction
crude oil
complex mix of hydrocarbons
lengths of the chain determines
the molecule’s properties and use
hydrocarbons are separated into different size classes and are chemically formed, created specialized fuels for many uses
hydraulic fracturing
breaking rock formations to release oil or gas trapped in impermeable shale
what is hydraulic fracturing used for
secondary extraction and to tap new deposits
what do drilling platforms withstand
wind, waves and currents
where are people drilling now
deeper and deeper waters
natural gas extraction and processing
sent by pipeline to refinery
converted to liquefied natural gas
uses for natural gas
production of plastics, fertilizers, and synthetic fibers
what has fewer effects than coal or oil
natural gas
burning fossil fuels takes what
carbon from long-term storage underground and releases it into the air
what is the greatest greenhouse gas
carbon dioxide
what has the greatest impact of fossil fuel use
carbon dioxide
methane is a
greenhouse gas
what does using alternative fossil fuels produce
more carbon dioxide
what is the primary energy source that are continuously replenished
renewable energy
examples of renewable energy
falling water
earths heat
oceans tides and waves
general challenges of renewable energy
-renewable are diffuse and intermittent
-technologies to harvest still being developed
benefits of renewable energy
-far fewer environmental impacts
-infinite energy source
what is hydropower supplied by
hydrologic cycle
what is the most abundant renewable energy use
what is hydropower used for
electricity generation
ex of hydropower
run of rivers
advantages of hydropower
Fuel and pollution free
Relatively inexpensive
Also provides flood control and water storage
Continuous electricity
disadvantages of hydropower
Loss of land
Ecosystem disruption
Initial cost
sources and supplies for wind power
driven by sun
kinetic energy from wind collected by wind turbines
advantages of wind power
No fuel, no pollution
CO2e free
Disadvantages of wind power
Impacts to wildlife
solar energy
radiant energy of the sun
passive solar technology
uses solar energy without mechanical devices
natural lighting and heating
active solar
uses mechanical devices
rooftop solar panels
concentrating solar power system
rooftop solar panels
solar water heater
advantages of solar power
widely available
few environmental costs
Disadvantages of solar power
biomass energy
energy contained in wood and other plant matter
where is biomass energy derived from
solar energy
biomass can be ….to produce …
examples of biomass
crop residue
advantages of biomass
Carbon neutral
Emits less NO2 and SO2 than fossil fuels
Evenly distributed
disadvantages of biomass
impacts on food supply
land clearing
geothermal energy
uses heat energy from earth’s interior
in what ways is geothermal energy harnessed
Dry-steam power plants
Flash-steam power plants
Ground-source heat pumps
advantages of geothermal energy
reliable and relatively inexpensive
pollution free
disadvantages of geothermal energy
Can be overused
Start-up cost high
ocean energy
takes advantage of tides, waves, and temperature differences
tidal power
driven by moon
turbines turned as tides enter and leave nays
waves power
uses kinetic energy of waves
advantages of ocean energy
fuel free
minimal emissions
disadvantages of ocean energy
disruptive to ecosystems
used primarily in the united states for electricity generation
remains of ancient organisms, modified underground for long periods by temperature and pressure
coal, oil and natural gas
the worlds most abundant fossil fuel
a mixture of hundreds or thousands of different hydrocarbon molecules
primary fuel used in the united states for space and water heating
natural gas
created very slowly and considered nonrenewable at current extraction rates
coal, oil, natural gas
used in the united states as a source of vehicle fuels
produces the least carbon dioxide per unit energy when combusted
natural gas
Many pollutants from coal-fired power plants are properly managed today. Which of the following is currently considered to be the biggest threat to the environment?
carbon dioxide
All fossil fuels, including coal, are considered an indirect form of ____________ energy
Where is electricity made at a coal-fired power plant?
During peak usage, what happens to the cost of electricity?
it almost always increases
What color smoke coming from a coal-fired power plant would indicate wasted fuel?
You are a scientist working on a Natural Resource Damage Assessment. Who do you work for?
federal government
What type of eggs were removed from at-risk beaches following the Deepwater Horizon spill?
You are interested in harnessing the gas that was released as a byproduct of the Deepwater Horizon spill. What gas are you searching for?
best summarizes the impact of the Deepwater Horizon spill
Some scientists believe there was great environmental impact from the Deepwater Horizon spill, others believe the impact was minimal.
What does the yellow line represent?
The amount of global warming that is likely to occur if CO2 emissions cease immediately and CO2 concentrations continue at their current level.
Which line is not a computer-generated forecast?
the black line representing 20th century data
The accuracy of computer forecasts of global climate change is measured by _____.
backcasting to see if the models accurately describe the weather and climate in the past
Halting deforestation and planting trees in large areas that presently have no trees is part of the stabilization wedge addressing _____.
Biofuels and wind energy are examples of the stabilization wedge called _____.
renewable energy
CAFE standards in the United States are part of the stabilization category of _____
efficiency and conservation
“Conservation of energy” refers to the fact that _____.
energy cannot be created or destroyed but can be converted from one from to another
chemcial energy is a form of ____ energy
in your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP
cellular respiration
what are by-products of cellular prespiration
heat carbon dioxide and water
cooling effect of sweating best represents ____.
latent heat transfer
when plants use sunlight in photosynthesis. the plants are using the form of ___
electromagnetic radiation
what converts mass to energy
nuclear fission
When a windmill turns to generate electricity, the amount of kinetic energy input _____.
is more than the amount of electrical energy produced
The oxygen-rich atmosphere of Earth is mainly the result of _____.
photosynthetic organisms
The total amount of moisture in the air is highest when relative humidity is _____.
high and temperatures are high
Every day tremendous amounts of the sun’s energy strikes Earth. Why doesn’t Earth overheat?
the energy is ultimately radiated back to space
The most abundant greenhouse gas, which is not considered to be adding to global warming, is _____.
water vapor
When monthly measurements of carbon dioxide levels are taken in a remote island in Hawaii, the levels cycle up and down, depending upon the season of the year. This is primarily due to changes _____.
in the net productivity of the terrestrial ecosystems
How did the University of Florida help address the problem of global warming?
The athletic program reduced local energy consumption and planted trees
The Neutral Gator program used methods that _____.
decreased production of carbon dioxide and reduced the amount of carbon dioxide already in the atmosphere
The University of Florida’s athletic program became carbon neutral because it _____.
promoted programs that reduced fossil fuel use and sequestered carbon
How does planting trees offset carbon generated by the University of Florida athletic program?
The planted trees will sequester carbon dioxide from the air as they grow
It has been estimated that black carbon is responsible for _____ of the planet’s warming.
Ignoring migration, the age structure of a human population likely to increase in size will have what shape?
Ignoring migration, the age structure of a human population likely to decrease in size will have what shape?
inverted pyramid
Ignoring migration, the age structure diagram of a human population likely to maintain a relatively stable size will have what shape?
a rectangle tapering toward the top
these nations have the lowest rates of population growth today
nations in this group have populations with many more people in the pre-reproductive age class than in the post-reproductive class
these nations will experience the cast majority of population growth in the coming decades
a high proportion of the nations have total fertility rates below replacement level fertility
some nations are in the transitional stage of the demographic transition model
women in these nations have higher access to education, employment and contraception
these nations account for only about 20% of the global human population
In the second stage of the demographic transition, called the mortality transition, the death rate _____ while the birth rate _____.
decreases, remains high or increases
About a century ago, the population in Latin America moved from an agricultural to an urban-industrial base. During this period birth rates _____, death rates _____, and the overall population _____.
stayed about the same, decreased, and the population grew even faster
human well-being is lowest where population growth rates are _____.
high and consumption rates are low
Death rates in poor countries are typically _____ than in wealthier countries. This difference between poor and wealthy countries is greatest in people who are the _____ members of the population.
higher, youngest
Malthus found that populations in the American colonies were increasing _____ than populations on the European continent due to _____.
faster, greater resources were available in the American colonies
Because human suffering _____ as the human population approaches its carrying capacity, sustainability of the global human population must be _____ the carrying capacity of the Earth
increases, below
The IPAT formula is used to estimate the _____.
ecological footprint of a society
If everyone in the world had the ecological footprint of people currently living in the United States and Canada, the world would _____
exceed its biocapacity by five times over
Over the past 2 million years, Earth’s climate has _____
cycled between cold and warm periods
Global warming over the past 200 years is most closely associated with _____.
the industrial revolution
The melting of icebergs in the Arctic Ocean will result in _____.
more solar radiation absorbed in this region
the greatest source of greenhouse gases in industrialized countries is ____
power stations
Matter is made of
one or more elements
chemical that cant be broken down or separated into other chemicals
physical and chemical properties of elements are attributed to the characteristics of their most basic units
two or more atoms held together by chemical bonds
what is the most important molecule in the ecosystem
4 most common elements
hydrogen, carbon, oxygen, nitrogen
positively charged
neutral particles
elements atomic number
atoms of a particular element always have the same unique number of protons
negative charge
property responsible for gravitational attraction of all matter to all other matter
atoms of an element with different numbers of neutrons
isotopes with nuclei that are unstable and that can break away
length of time that it takes for half of the collection of atoms of a radioisotope to decay
Atoms combine with other atoms to form what?
molecules that are made up more than one element
two common compounds
H2O and CO2
atoms in a molecule are held together by
chemical bonds
strength of a chemical bond is measured by what
the energy required to break it
covalent bonds
strong bonds formed when atoms share electrons
how can strong bonds be formed
when one atom transfers one of its electrons to another atom
atom donating the electrons have a …..
net positive charge
atoms receiving the electrons have a …..
net negative charge
electrically charged atoms or molecules
Ionic bonds
bonds between the ions
are compounds formed by ionic bonds molecules?
Dipole bonds
weaker bonds that form between atoms and molecules as a consequence of shifts in electrical charge
the strength of dipole bonds depends on what
the extend of the polarity, or difference in charge between the molecules
where are dipole bonds important
in biological functions
ability of a chemical to dissolve in a particular liquid
non polar molecules are …
not very soluble in water
chemicals dissolved in water may…
shift the amount of H+ ionic relative to OH- ions
pH scale
quantitative representation of the relative amounts of hydrogen and hydroxyl ions in a liquid
pure water pH is
atoms are made up of
protons, neutrons and electrons
number of protons
how many atoms here are (positive)
# of electrons equals
# of protons
organic molecules are the
primary structural and function component of life
carbon atoms covalently bonded to
hydrogen and other atoms
Inorganic molecules are
not made of carbon and hydrogen
examples of inorganic molecules
water and they wither have carbon or hydrogen
simplest organic molecule
organic molecules types
hydrocarbons and carbohydrates
hydrocarbons made of
carbon and hydrogen
made of carbon, hydrogen, oxygen
examples of carbohydrates
sugar and glucose
where does glucose come from
what do water and carbon dioxide xreate
the mass
plants make
carbohydrates to use for energy; make their own food
what does photosynthesis require
energy to split the carbon bonds in the CO2 and the water bonds to H2O
when is energy given off during photosynthesis
when carbon, carbon hydrogen, carbon oxygen, oxygen hydrogen and oxygen bonds are formed into glucose and oxygen
when plants or us break apart then
energy is given off
macro molecules or polymers
small organic molecules linked together in long chains
polymers of simple sugar
example of polysaccharides
starch and cellulose
break it apart to get energy and become apart of us
attach in a different way and is really hard for plants and animals to break apart; this gives plants that structure to stand up
organic molecules example
lipids (fat)
what are lipids
long chains of carbon and hydrogen and a shorter region with one to several oxygen molecules
ex of lipids
fats and oils
lipids are not…
water soluble
what is lipids important for
energy stroage
what are examples of macromolecules
what are proteins
polymers of amino acids
proteins are made of
chains of 100 to 1000+ amino acids
proteins fold into
particular shapes yielding functions
yielding functions of proteins
structural, transportation of material, energy storage, and catalysts
nucleic acids are
polymers of nucleotides
Deoxyribonucleic acid
hereditary material in humans, plants, ect.
traits coded in sequence of bases
ribonucleic acid
use ribose as the sugar
protein synthesis
organic molecules need
carbon, hydrogen and oxygen
dynamic homeostasis
the process by which systems adjust to change so that minimize how much features or processes vary from their normal value
Negative feedback
output from the system acts as an input to the system
ex of negative feedback
if you get hot, you sweat
positive feedback ex
as climate warms, sea ice absorbs the sunlight and ice melts
Exponential growth
small populations most likely
the more complex an organism is the
less the doubling period is
population growth rate
rate at which a population changes
total population growth
(birth rate + immigration)-(death rate +emigration)
Type I
really high percentage chance of survival but closer you get to 100% then you start to die off
Type II
you have the same percentage of dying no matter what age you are
Type III
really high chance of dying when you are young and as you get older the more likely to survive
fertility rate
potential number of offspring that an average female can produce if she survives to old age
population grow rate ______ as fertility rate ________
population growth is influenced by
generational time
where an organism lives
ecological niche
various activities that define an organism’s role in an ecosystem
water balance coefficient
general index of the water available in a region
open watershed
drained by rivers that make their way to the sea
closed watershed
do not drain into the sea; drain into inland lakes
water is mostly returned to surface water bodies and aquifers
Example of nonconsumptive
hydroelectric power
water is mostly removed from surface water bodies and aquifers
ex of consumptive
irrigation and industrial cooling
crop irrigation has huge losses due to
evaporation and runoff
Low-energy precision application
decreases water usage by more than 60%
Drip irrigation
irrigation efficiency can be greater than 95%
process of removing salts and other chemicals from seawater
boil water and recondense the steam
reverse osmosis
filter water through selective membrane
Intermolecular forces
weaker than bonds that hold molecules and compound together
what are intermolecular forces between
molecules, atoms, ions and compounds
4 kinds of intermolecular forces
dispersion forces
dipole-dipole interactions
ion-dipole interactions
hydrogen bonds
Dispersion forces
present in all molecules
o Electron cloud distorts
o Partial negative and positive charges attract each other
o Larger and heavier molecules have stronger dispersion forces
Dipole-dipole interactions
molecules with permanent dipoles are attracted to each other
stronger than dispersion forces
the primary thing that increased agricultural productivity during the Green Revolution inculed with of the following
fertalizer, crop breeding, pest control, and irrigation improvements
Ammonia is a common chemcial with the formula NH3 . What type of intermolecular foces are more important between molecules of this compound
hydrogen bonding
Xenon is a noble gas. Even though it doesnt normally react with other substances, under the proper condition it will form Xe2+ ions. what describes the formation of this ion
loss of 2 electrons from the larger area outside the nucleus
negative feedback processes tend to function within ecosystems to:
stabilize the ecosystem
what is the most basic source of immediate energy for most organism
when populations approach their carrying capacity, what happens to their resources
they become more scarce as growth rate becomes zero
after eating, glucose levels in the blood tend to increase. This increase causes the pancreas to release insulin. which converts glucose into glycogen
negative feedback
as ecosytem is defined as
all the biota and their physical and chemical enviroment within a specific area
what are animals such as earthworms and millipeds, which feed on dead organic matter called
what is not a step in the nitrogen cycle
plants release nitrogen into the air during cellular respiration
what are steps in the nitrogen cycle
-nitrogen is fixed by bacteria into the soil, allowingn it to be taken up by plants
-animals obtain nitrogen by consuming plants
-bacteria in the soil convert ammonia back into nitrogen that is released into the atmosphere
-animals and plants release nitrogen into the soil through waste materials and when they decompose
the total number of plant and animal species that a field biologist identifies along a mountain trail is an example of what
species richness
Image following a single water molecule through the hydrologic cycle. Which of the follwoing is a possible path for the water molecule to take
ocean to atmosphere to soil to plant
how is genetic variaition maintained in most population
through inbreeding
where does most of the mass of plants come from
carbon dioxide from the air and water from the soil
principles of ecosystm functions
-always open to gains and losses of matter and energy
-matter and energy can neither be created nor destoryed
-processes are self-regulated by interactions among their living and nonliving components
-change is inevitable and essential
nuclear energy is
energy contained in matter itself
in nuclear fission
nucleus of an atom splits to form two or more smaller nuclei
in the process of nuclear fission…
a small amount of the nucleus’s mass is converted to electromagnetic and kinetic radiation
when does nuclear fission occur
radioactive isotopes of particular elements decay
This decay is the process that
heats up the Earths interior
Electrical power is generated by taking advantage of what
the energy released by the decay of an isotope of the element URANIUM
Uranium mass number is
235 U
How does the nuclear fission occur with URANIUM
the uranium nucleus is split, high-energy neutrons are emitted, as well as other forms of energy. If these neutrons are sufficiently abundant, they can split the nuclei of there U atoms. The newly split atoms emit more neutrons, which then split into more nuclei.
compare the cost of nuclear power plant to cost of operating a power plant run by coal or natural gas
Much lower
-start up cost is very high
how is Uranium obtained
open pit mines
reactor core
the place where the fission takes place
what happens in the reactor core
the fuel assemblies produce high energy neutrons, that set the nuclear fission chain reaction in motion
does the steam that is powered by the turbine come in direct contact with the radioactive fuel assemblies
to extract the uranium you need…
large quantities of rock has to be removed and processed
consequences of nuclear
need large land
can put acid in water
most important by-product of nuclear power plants
excess heat
The controlled fission of uranium in the core of a nuclear reactor does what?
heats water or sodium, which is then used to produce steam to drive turbines and generate electricity
Normal operation of nuclear power plants produce…
high amounts of spent nuclear fuel that remains radioactive for hundreds of thousands of years
two kinds if high-level radioactive waste storage
spent nuclear fuel
fuel recycling
all the physical, chemical and biological factors and processes that determine the growth and survival of an organism or a community of organisms
is the branch of environmental science that focuses on the abundance and distribution of organisms in relation to their environment
living organisms
nonliving environments
ex of abiotic
ecosystems are connected by the
flow of energy and matter
ecosystem functions
flow of matter and energy and the processes influencing the distribution and abundance of organisms
ecosystem integrity
to the web of interactions that regulate ecosystem functions
dynamic homeostasis
process by which systems adjust to changes in ways that minimize how much features or processes vary from their normal values
regulation of temperature in your body is an example of
negative feedback
negative feedback occurs when
directional change in a process alters the system in a matter that reverses the direction of that change
positive feedback occurs when
directional change in a process alters the ecosystem so as to reinforce that change
all ecosystems are open to
inflows and outflows of matter and energy
ecosystem processes and functions are self-regulated by
dynamic homeostasis
When did domestication of plants and animals occur
pre-industrial age
parks and public land should preserve wild nature in its pristine state
-humans can have access to wilderness parks for their inspiration and beauty but should be protected from consumptive uses
public resources should be used and managed in a sustainable fashion to provide the greatest benefit to the greatest number of people
-value nature for the goods and services it provided human beings
all matter is made of one or more
most basic sub-unit of an element
two or mole atoms may be held together by chemical bonds to form
what is the most important molecule in ecosystem
4 most common elements in ecosystem
nucleus is surrounded by one or more negatively charged particles called
what is the overall charge of an atom
what is the property responsible for the gravitational attraction of all matter to all other matter
atoms of an element with different numbers of neutrons
some isotopes have nuclei that are unstable and can break away
-they spontaneously “decay”, emitting various combinations of high-energy protons, electrons and neutrons and radiation
the length of time that it takes for half of a collection of atoms of a radioisotope to decay
molecules that are made of more than one element
examples of compounds
atoms in a molecule are held together by
chemical bonds
Covalent bonds
strong bonds formed when atoms share electrons
examples of covalent bonds
Atoms that are held together by covalent bonds…
the electrons and electrical charge are shared equally between the atoms so the bond is nonpolar
atom donating an electron has a
positive charge
atom receiving an electron has a
negative charge
electrically charged atoms or molecules are called
bonds between ions are
ionic bonds
Dipole bonds
are weaker bonds that form between atoms and molecules as a consequence of shifts in electrical charge
strength of dipole bonds depends on the
extent of the polarity, or difference in charge between the molecules
because water molecules are polar, they form what
dipole bonds with other water molecules
hydrogen bonds
dipole bonds that involve hydrogen atoms
-responsible for the cohesive nature of liquid water
as liquid water heats up, the hydrogen bonds
without hydrogen bonds
water would boil at temperatures well below its actual freezing point
as liquid water becomes colder…
more hydrogen bonds form, pulling water molecules closer together
Water become ______ as it cools
what makes water an excellent solvent
the polarity of it
ability of a chemical to dissolve in a particular liquid
when the concentration of H+ increases, it is
when the concentration of OH- increases, it is
organic molecules
primary structural and functional elements of organisms
– made of carbon atoms covalently bonded to hydrogen and other atoms
inorganic molecules
compounds that are not made up of carbon and hydrogen
organic molecules composed entirely of carbon and hydrogen atoms
organic molecules made of carbon, hydrogen, and oxygen
basic source of energy in most organisms and an ingredient in the synthesis of numerous other organic molecules
fats and oiks
organic molecules made of long chains of carbon and hydrogen atoms and a shorter region with one to several oxygen molecules
important forms of energy storage
fats and oils
the shorter region of a lipid is
why are lipids not soluble in water
because of their nonpolar region
small organic molecules may be linked to one another to form these
simple organic molecules may be linked together to form much larger chains or networks
essential to the structure and function of organisms
polymers of simple sugar molecules
examples of polysaccharides
starch and cellulose
starch and cellulose are
polysaccharides composed of hundreds of glucose molecules
plants use this to store extra sugar
cellulose is the
primary structural constituent in plant tissues
one of Earth’s abundant organic molecule
difference between starch and cellulose
nature of the bond between adjacent glucose molecules
polymers made of nitrogen-containing organic molecules called amino acids
substances that promote chemical reactions without being consumed in the reaction
proteins that serve as catalysts are called
nucleic acid
polymers of chemical subunits called nucleotides
capacity to do work
the two forms of energy
kinetic and potential
First law of thermodynamics
the total amount of energy in the universe is constant
Second law of thermodynamics
every energy transformed increases disorder
disorder or disorganization in a system
least usable form of energy in the random motion of molecules
energy of light
electromagnetic radiation
electromagnetic radiation is transported as
the amount of energy carried by the different forms of electric magnetic radiation are determined by
full range of wavelengths
electromagnetic spectrum
which wavelengths are shorter than visible light
gamma rays, x rays
which wavelengths are longer than visible light
infrared radiation, microwaves, radiowaves
measure of the average kinetic energy of a collection of molecules
heat can move in 4 ways
conduction, convection, radiation, latent heat transfer
conduction is the
direct transfer of heat by means of the collisions of molecules
example of conduction
when you touch a hot pot, heat moves from molecules on the pot to the molecules on your fingertips
Convection occurs because
warm regions in a gas or liquid become less dense and rise, causing the gas or liquid to circulate
release of electromagnetic energy
-all matter is constantly losing heat by this
Latent heat transfer occurs as the
molecules with the highest kinetic energy evaporate, leaving behind molecules with lower kinetic energy and temperature
potential energy associated with the formation or breakage of bonds between atoms is called
chemical energy
energy contained in the structure of matter itself is called
nuclear energy
according to E=mc2, every tiny amount of mass contains
enormous amounts of energy
nuclear fission
occurs when the nucleus of an atom is split, producing two or more smaller nuclei and a great deal of electromagnetic and kinetic energy
nuclear fusion
occurs when atoms collide with so much energy that their nuclei fuse, forming an atom of a new element
energy unit for electricity
what to plants produce as a by-product
the force caused by the pull of gravity on a column of are is
atmospheric pressure
Lowest layer; troposphere
air we breathe
what happens in the air in the troposphere
air at low altitudes is warmed by heat radiating from Earth’s surface. As the air near the ground becomes warmer, it expands, which causes it to rise. As it rises, it cools, and eventually sinks back to the surface
Ozone is effective in
absorbing and scattering the abundant UV light that strikes Earth’s upper atmosphere
vapor pressure
relative contribution to total atmospheric pressure
At any particular temperature..
the air can only hold so much water
Saturation vapor pressure
the amount of water air can hold at a given time
saturation vapor pressure ________ as the temperature ______
relative humidity
measure of the extent to which air is saturated, expressed as a percentage
relative humidity of a mass of air ____ and ____ with temperature
clouds account for how much of the light that is reflected back
atmospheric conditions such as temperature, humidity, and rainfall that exist over large regions and long periods
short-term variations in local atmospheric conditions
On a hot sunny summer day, humid air becomes warmer and then
air expands it is less dense, it rises. As the air rises in altitude, it begins to cool. When the air mass cools to its dew point, water condenses, forming a cloud and perhaps a rain shower
where air is descending…
atmospheric pressure rises (usually indicating dry conditions)
because the earth’s surface is curved,
the amount of sunlight reaching its surface varies with latitude
uneven distribution of solar radiation results in
significant differences in air temperature and pressure around the globe and causes wind cells
because the equator experiences the most heating, the air
is warm, humid air rises, it cools, and water condenses, forming rain
Hadley cells
the air from the equator then diverges northward or southward forming tow convection currents
what do wind cells influence
seasons occur because
earth is tilted
annual variation in temperature and rainfall at a location is influenced by the
seasonal movements of wind cells above it and its position on a continent
birth rate
number of births in the population per unit of time expressed as a percentage of the population
death rate
number of individuals dying per unit of time expressed as a percentage of the population
death rate is also known as the
mortality rate
how to find the population growth rate
(birth rate+immigration rate)-(death rate+emigration rate)
type I survivorship
most likely to die of old age
examples of type I
large animals and predators that have few enemies (humans )
type II survivorship
probability of dying is the same at every age
examples of type II
type III survivorship
very young have the greatest probability of dying because they are most easily taken by predators or are most vulnerable to disease
examples of type III
which survivorship is the most common one found in nature
type III
rate of reproduction is known as
fertility rate
what happens at the carrying capacity
the birth rate equals the death rate, and the population growth rate stalls at zero
what happens when a population exceeds their carrying capacity
their use of resources exceeds the rate at which resources are supplied and the resources become scarce
what 2 factors do the consequences of scarce resources depend on
the speed with which the population growth rate responds to the diminished supply and the rate at which the depleted resources are able to recover relative to the continued demands of the population
when the population declines what happends
the demand for resources eases and the supply or resources increases
what in an important factor that influences the growth rate, birth rate and death rate
complex environment in which an organism is found and upon which is depends for survival
organisms habitat includes
nonliving, environmental elements (temperature, humidity, soil) and living conditions like insects
size of an organisms habitat depends on the
size of the organism and its ecological needs
complex, encompassing every interaction between and organism and its ecosystem
ecological niche
ecological niche includes
what the organisms eats, what eats the organism, and the effects of the organisms activities on the flow of energy and matter through the ecosystem
natural selection
individuals in a population that are most fir to survive and leave more offsprings
what did the finches use different beaks for
feeding on small insects, or eggs
what are examples of breeding barriers
closely related species that are isolated from one another
(ex. geographic, temporal, behavioral)
natural selection has resulted in
a variety of mechanisms that prevent interbreeding
when did the pre-agricultural period grow
as humans expanded into new territories and developed new tools
birth and death rates are highly correlated with the
level of economic development
a human population is _______ long before it nears its ___________
carrying capacity
when you are at your carrying capacity, there is what
competition for resources
increase in what when there you are toward the carrying capacity
an estimate of the area of land needed to supply human demands for resources
ecological footprint
as a country becomes more affluent…
its ecological footprint is increasingly defined by its use of fossil fuels and nuclear and hydrologic power
a measure of the area and quality of land available to supply a population with resources
human impact is determined by
population, size, affluence, and technology
a change in one factor in the IPAT equation causes
another factor to change
Chinas approach to population growth
One-Child Policy
India’s approach to population growth
family planning should be voluntary and decisions would be made in each individual state
educated women
Mexico’s approach to population growth
used communication, education, counseling and contraceptives to encourage people to not have sex
energy flow
transfer and transformation of high-energy organic molecules
primary producer
-first level
-transform energy from sunlight or certain inorganic chemicals into high-energy carbohydrates
primary consumers
animals that need on primary producers
secondary consumers
feed directly on the herbivores
tertiary consumers
organisms that feed on secondary consumers
organisms that feed on nonliving organic matter
food that can be consumed by higher trophic levels
biomass energy
most of the energy that is consumed by any organisms is
burned in respiration or lost as waste
the amount of energy available to each trophic level is
less than the energy available to the trophic level beneath it
organisms that feed at higher trophic levels must
expend more energy per unit of biomass to obtain their food
the stability of a community food web is directly related to the
diversity of its species and the complexity of their connections
hydrologic cycle
the distribution and flux of water through Earth’s biogeochemical system
what drives the hydrologic cycle
solar energy and gravity
three phases of water in the hydrologic cycle
solid ice, liquid water, gaseous water vapor
three general fates of liquid water when it is on the ground
-it may evaporate; back to the atmosphere
-flow across Earth;s surface into streams and lakes and eventually the ocean
-percolate through the soil and become groundwater
water evaporating from leaves
rainwater that falls on land that may flow across the surface
-eventually enters lakes and streams
what does the movement of water influence
Earth’s biogeochemical cycles
Human impacts on the hydrologic cycle
-diverted large qualities of water from rivers and streams for agricultural, industrial and residential use
what are the key steps in the carbon cycle
photosynthesis and cellular respiration
how do organisms access carbon
cellular respiration
where is most of the carbon stored in living biomass found
terrestrial ecosystems
what has a profound effect on Earth’s carbon cycle
fossil fuels
when did burning fossil fuels increase exponentially
Industrial revolution
what is the most abundant element in Earth’s atmosphere
what are the 3 reasons for the difference in abundance in nitrogen
1. it is not stable part of the crystal structure of any of the minerals in rocks
2. most molecular forms of nitrogen are volatile and tend to migrate to the atmosphere
3. does not react with other gases in the atmosphere and is very stable in the presence of solar radiation
how does nitrogen enter the bisphere
through nitrogen fixation
Today’s world
assume that anthropogenic greenhouse emissions cease immediately and that CO2 in the atmosphere will stay at current levels
Business as Usual
assume that individuals and governments will take no actions to reduce emissions and the annual CO2 emissions will continue to increase
Sustainable World
assume that people and their governments will take significant actions to slow the increase in CO2 emissions
are derived directly from plant materials, such as corn or wood
variety of life in all its forms and combinations and at all levels of organizations
The number of species, their relative abundance, and their arrangement in space are measures of
community biodiversity
species richness
the total number of species in each sample
species everness
relative abundance of the different species in a community
structural complexity
the three-dimensional distribution of species and biological features
Inbreeding ____ genetic diversity and _____ the chance of genetic diseases
general index of the availability of water in a particular region
water balance coefficient
area of land from which rainfall drains into a river or lake
open watersheds
drained by rivers that eventually make their way to the sea
closed watersheds
inland basins that do not drain to the sea
nonconsumptive uses
activities that use water and then return it in streams or aquiers
examples on nonconsumptive uses
generation of hydroelectric power and the disposal of wastewater in spetic systems
consumptive uses
much of the water is not returned to streams or aquifiers
what holds significant portions of Earth’s fresh water
saturated sediments and rocks
recharge zone
area where water flows directly between the soil surface and the water table
discharge zones
groundwater flows to the surface
strategies for reducing the use of water
improved technologies for irrigating crops, recycling of municipal and industrial water, and more efficient use of residential water
when is the rate of evaporation greatest
in regions where irrigation is mostly used
process of removing salts and other chemicals from sea water
to main methods of desalination
distillation and reverse osmosis
boiling water and condensing the steam
filtering water through a selective membrance
reverse osmosis
system of land management used to grow domesticated plants and animals for food, fiber or energy
what played important roles in the origins of agriculture
climate change, cultural process, and population growth
during the agricultural period what was happening to the climate and seasons
climate were getting warmer and dry seasons were growing longer
humans and their domesticated plants and animals have
what did technological and cultural innovations do to the agricultural production
increased and reduced the need for humans labor
green Revolution
period during which global agricultural productivity has increased many times over
what was the Green Revolution result of
development of modern fertilizers, herbicides and pesticides.
secondary energy source that is derived from primary energy sources
as a battery is used, the strength of its electrical potential
how was coal formed
formed from plants that lived in swamps hundreds of millions of years ago
chemical energy in coal is transformed into
electricity in coal-fired power pleants
burning coal is a significant contributor to
global warming
what 3 geological conditions must be met in order for an oil reservoir to form
1. shallow sea with large quantities of aquatic organisms that died and sank to the bottom and covered in sediments
2. oils had to migrate upward into a porous rock reservoir
3. reservoir rock must have been covered by a layer of imperable rock that prevented oil from seeping to the surface
how is oil extracted
crude oil is pumped from underground reservoirs and sent to oil refiners to be converted into gasoline and other petroleum products
natural gas extraction
pumped from underground reservoirs, purified and sent to consumers by pipeline
renewable energy sources are abundant on the global scale but
their availability in particular locations are limited
renewable primary energy resources are based on
energy flows that are continuously replenished
Primary challenge of using many renewable energy resources is that they are
diffuse and intermittent
in order to make use of most renewable energy resources, we must
capture and convert their diffuse energy flows into more concentrated forms
no single renewable energy resource can significantly
reduce our dependence on nonrenewable resources
four general categories of challenges to the widespread use of renewable energy
-unfamiliar technologies
-economies of scale
-externalized costs
-limited consumer knowledge and understanding
energy of water moving under the force of gravity
hydroelectric power
electricity generated by suing the kinetic energy of moving water to turn a turbine
hydropower is renewable because
the liquid water in lakes and streams is constantly being replenished in the hydrologic cycle
passive solar power
using energy of sunlight without relying on electrical or mechanical devices

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