Ch 4 exam

study of how organisms interact with one another and with their non-living environment

term for thousands of species that cant be seen with the naked eye

genetic diversity
slight variations in individuals among a population
place or environ where a pop normally lives
distribution; range
the area over which we can find a species
a community; biological community
all the populations of the different species living and interacting in an area

membrane of air around the planet


-troposphere:inner layer; 11 miles above sea level;most of air (N and O)


-stratosphere: lower portion has enough ozone to filter out sun’s UV radiation


consists of earth’s water

earth’s crust and upper mantle

portion of earth in which living organisms interact with one another and with their nonliving environment



three interconnected factors life depends on

-one way flow of high-quality energy

-the cycling of matter

-gravity (which allows the planet to hold ts atmosphere and causes the downward movement of chemicals in the matter cycles)


much of it’s energy is reflected or absorbed by chemicals, dust, and clouds in the atmosphere


80% of energy that gets through warms the troposhere and evaporates/cycles water thru biosphere


1% generates wind


.01% is used to fuel photosynthesis

natural greenhouse effect

most of solar radiation hits the surface of earth; degraded into longer-wavelength infrared radiation which reacts with greenhouse gases in the troposphere


radiation causes these molecules to release infrared radiation with even longer wavelengths which reacts with molecules in the air, it increases their kinetic energy and helps the troposphere and earth’s surface warm


without it the earth would be too cold for life as we know it


large regions chracterized by a distinct climate and specific species adapted to it


water: aquatic life zones

range of tolerance
each population has different tolerance levels for its chemical or physical environment
law of tolerance

the existance distribution

and abundance of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the range tolerated by that species

limiting factor principle
too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance

limiting factors include…

land: precipitation; soil nutrients


aquatic: temp; sunlight; nutrient availability; dissolved oxygen content; salinity

phosphorous cycle
little in air because soil conditions dont allow bacteria to convert to gas;

cycle is slow

phosphate ions found in phosphate salts in terrestrial rock; erosion releases phophorous as phosphate ions which are taken by plant roots

can be lost if washed into streams and deposited as sediment in ocean

limitin factor because most soils contain little phosphate

human affecting phosphorous cycle?
-we mine large quantities of phosphate rock for fertilizers

-we reduce phosphate in tropical soils when we cut down forests

-we disrupt aquatic systems with phosphate runoff


specialized consumers that recycle organic matter in ecosystems by breaking down dead organic matter or detritus to get nutrients


detritus feeders and decomposers that feed on detritus

aerobic respiration
uses oxygen to convert organic nutrients back into carbon dioxide and water
anaerobic fermentation/fermentation
breakdown of glucose in the absence of oxygen to form methane gas, ethyl alcohol, acetic acid, and hydrogen sulfide
Biological diversity/biodiversity

one of the earth’s most important renewable resources


-genetic diversity

 -species diversity

-ecological diversity: variety of ecosystems

-functional diversity: biological and chemical processes needed for the survival of the species,communities, ecosystems

ecological efficiency
percentage of usable energy transferred as biomass from one trophic level to the next

net primary productivity

rate at which producers use photosynthesis to store energy minus the rate at which they use some of this stored energy through aerobic respiration


this covering over most land that is a complex mixture of eroded rock, mineral nutrients, decaying organic matter, water, air and living organisms
soil profile
cross-sectional view of the horizons in soil
surface litter layer/ O horizon
undecomposed/partially decomposed leaves, twigs. crop wastes, animal wastes, fungi
topsoil layer/A horizon
porous mixture of partially decomposed organic matter, called humus, and some inorganic mineral particles

soil horizons

O horizon-leaf litter


A horizon-topsoil


B horizon-subsoil


C horizon-parent material; lies on bedrock: unweathered parent rock


B&C contain most of a soil’s inorganic matter


downward movement of water through soil
water seeps down and dissolves various minerals and organic matter in upper layes, carrying them to lower layers
soil texture
relative amounts of the different sizes and types of these mineral particles (clay,silt,sand,gravel)

hydrologic cycle

evaporation; transpiration; condensation; precipitation; infiltration; percolation; runoff

condensation nuclei

tiny particles on which droplets of water vapor can collect


volcanic ash, soil dust, smoke, sea salts, particulate matter

how have humans affected water cycle?

1. we withdraw large quantities of fresh water

2. we clear vegetation from land for agriculture, mining, etc. which increases runoff; increase flooding

3. we modify water quality by adding nutrients and other pollutants

4. earth’s water cycle is speeding up resulting in warmer climate

carbon cycle

too much CO2 removed will cool atmosphere; too much generated makes it warmer


-fossil fuels:buried deposits of dead plant matter compressed and form coal and oil


CO2 dissolves in ocean and taken in by aquatic producers; as ocean warms, some dissolved CO2 returns to atmosphere




How do we affect carbon cycle?

-we clear trees/plants that absorb CO2


-we add large amounts of CO2 by burning fossil fuels

Nitrogen Cycle

-N2 gas cant be absorbed by animals


-lightening causes N2 and O2 to react and produce nitrogen oxide (NO)

 -Nitrogen fixation: aquatic/soil/root bacteria fix N2 into ammonia


-unabsorbed ammonia can be nitrified into nitrite ions(toxic) and nitrate ions by aerobic bacteria


assimilation:plant roots absorb dissolved substances


ammonification: decomposer bacteria covert detritus into simpler nitrogen containing inorganic compounds and water-soluble salts


-denitrification: nitrogen leaves soil anaerobic bacteris convert back into nitrite and nitrate ions, and then into N2 & N2O

we affect nitrogen cycle?

1. add nitric oxide(NO) to atmosphere burning fuel

2. add nitrous oxide (N2O) through anaerobic bacteria on wastes/fertilizers

3. release large amounts of N stored in soils and plants into N gas

 4. add excuess nitrates into runoff

5.remove N from topsoil wehn we harvest, irrigate, burn


sulfur cycle
much stored underground in rocks uncluded sulfate salts in ocean sediments

hyrdogen sulfide released from volcanoes and organic matter in swamps, bogs broked down by anaerobic decomposers; poisonous

sulfur dioxidefrom volcanoes; sulfate salts from sea spray dust storms and forest fired

marine algae produce DMS which serve as nuclei; coverted to sulfur dioxide which is converted to sulfur trioxide and sulfuric acid

bacteria convert to sulfide ions

we affect sulfur cycle
-we burn sulfur-containing coal/oil

-we redine sulfur containgin petroleum

-we convert sulfurcontaining metallis mineral oils