Campbell and Reece Chapter 54 Flashcards
(88 cards)
1
Q
Ecosystems
A
individual communities and their abiotic communities
2
Q
Ecosystem interaction is complex because…
A
there are abiotic factors and biotic factors
3
Q
Energy flow
A
passage of energy through an ecosystem
4
Q
Primary producers
A
autotrophs, producers, form the beginning of the food chain by capturing the sun’s energy through photosynthesis
5
Q
__ are most critical on land, ___ in aquatic environments
A
plants, algae/cyanobacteria
6
Q
consumers
A
heterotrophs, organisms that extract energy from organic molecules produced by other organisms
7
Q
herbivores
A
consumers that consume plants
8
Q
carnivores
A
consumers that consume other animals
9
Q
omnivores
A
consumers that consume both plants and animals
10
Q
detritivores
A
eat detritus
11
Q
detritus
A
dead organic matter that includes animals’ carcasses, leaf litter, and feces
12
Q
decomposers (saprotrophs)
A
microbial heterotrophs that supply themselves with energy by breaking down organic molecules in the remains of all members of the food chain
13
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food web
A
complex of interconnected food chains in an ecosystem
14
Q
trophic levels
A
levels of predation organization
15
Q
ecological pyramid
A
graphical representation of the relative energy found at each trophic level
16
Q
pyramid of numbers
A
shows the number of organisms at each trophic level in a given ecosystem, with a larger area illustrating greater numbers for that section of the pyramid
17
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pyramid of biomass
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illustrates the total biomass at each successive trophic level
18
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biomass
A
quantitative estimate of the total mass, or amount, of living mater; it indicates the amount of fixed energy at a particular time
19
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pyramid of energy
A
indicates the energy content, often expressed as kilocalories per square meter per year, of the biomass of each trophic level
20
Q
gross primary productivity (GPP)
A
rate at which energy is captured during photosynthesis in an ecosystem
21
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net primary productivity (NPP)
A
energy that remains in plant tissues after cellular respiration has occurred
22
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secondary productivity
A
energy available for biomass production by consumer organisms
23
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factors affecting primary productivity
A
- efficiency of plants
- availability of resources
- severity of human modification on environment
- degree of maturity of environment
24
Q
primary productivity and species richness are __
A
inversely related
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reasons primary productivity and species richness are inversely related
- less productive > patchy distribution of resources > reduced competition
- fertilizers increasing productivity
- ocean depths > resource poor
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three characteristics that describe toxins
persistence, bioaccumulation, biological magnification
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persistence
characteristics of toxins that describes toxins that are extremely stable and may take many years to break down into less toxic forms
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bioaccumulation
buildup of toxin in an organism's body
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biological magnification
increase in concentration as the toxin passes through successive levels of the food web
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biogeochemical cycle
cycle that describes the movement of matter from one organism to another and from living organisms to the abiotic and back again
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four biogeochemical cycles
carbon, hydrologic, nitrogen, phosphorous
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What percent of the atmosphere is CO2?
0.04%
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What forms of carbon are in the carbon cycle?
CO3/2- and HCO3/-
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Carbon cycle
global movement of carbon between the abiotic environment, including the atmosphere and ocean, and organisms is known as the carbon cycle
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steps of the carbon cycle
1. Producers fix CO2 into complex organic compounds
2. Cellular respiration returns CO2 to the atmosphere
3. Coal beds store carbon
4. Marine organisms produced underground deposits of oil/natural gas
5. Combustion returns carbon in oil, natural gas, and wood to atmosphere
6. Stored in shells of marine organisms (forms limestone at death)
7. geological uplift exposes limestone
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fossil fuels
vast deposits of carbon compounds, the end products of photosynthesis that occurred millions of years ago
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Nitrogen facts
- part of proteins, nucleic acids, and chlorophyll
- atmosphere is 78%
- N2 is so stable > takes a lot of energy to break bonds
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Nitrogen cycle
cycle in which nitrogen cycles between the abiotic environment and organisms
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steps of nitrogen cycle
1. nitrogen fixation using nitrogenase and heterocyst's
2. nitrification to convert nitrates
3. assimilation for roots to absorb
4. ammonification to form ammonium ions
5. denitrification to reduce to gaseous nitrogen
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nitrogen fixation
conversion of gaseous nitrogen to ammonia (NH3)
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nitrogenase
enzyme employed by nitrogen-fixing bacteria to break up molecular nitrogen and combine the resulting nitrogen atoms with hydrogen
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nodules
oxygen-excluding swellings on the roots of legumes such as beans and peas and some woody plants that nitrogenase lives in
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leghemoglobin
oxygen-binding protein similar to hemoglobin that provides bacteria with enough oxygen to respire
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nitrification
the conversion of ammonia or ammonium to nitrates
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assimilation
process in which roots absorb ammonia, ammonium, or nitrates that nitrogen fixation and nitrification formed and incorporate the nitrogen into proteins, nucleic acids, and chlorophyll
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ammonification
conversion of organic nitrogen compounds into ammonia and ammonium ions
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ammonifying bacteria
bacteria that perform ammonification in both the soil and aquatic environments
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denitrification
reduction of nitrate to gaseous nitrogen (N2)
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nitrogen oxides
oxides produced from atmospheric nitrogen due to high temperature of combustion
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photochemical smog
mixture of several air pollutants that injure plant tissues, irritate eyes, and cause respirator problems
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acid deposition
process in which acids such as nitric acid and nitrous acids leave the atmosphere
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effects of acid deposition
- decreases pH of surface water
- promotes global warming
- depletion of ozone in the atmosphere
- alters soil chemistry
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phosphorous cycle
cycle in which phosphorous cycles between terrestrial and aquatic environments
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phosphorous does not exist in ___ state, never enters __
gaseous, atmosphere
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steps of phosphorous cycle
1) erosion through runoff releasing inorganic phosphate
2) Phosphate is absorbed by roots
3) Algae/aquatic plants absorb dissolved phosphates in aquatic environments
4) Phosphate is lost to ocean thru rivers/streams
5) Uplift resurfaces phosphates as terrestrial surfaces to be eroded
6) Mined for agricultural use in fertilizers
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Hydrologic cycle
cycle in which water continuously circulates from the ocean to the atmosphere to the land and back to the ocean
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water facts/importance
- medium for chemical reactions
| - transport of materials within cells
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steps of hydrologic cycle
1. Precipitation - atmosphere > land
2. Evaporation - water > clouds
3. Transpiration - water vapor > atmosphere (97%)
4. Water flows in rivers/streams to estuaries
5. Water percolates and becomes groundwater
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transpiration
the loss of water vapor to the atmosphere (roughly 97%)
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estuaries
area where fresh water meets the ocean
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runoff
movement of surface water from land to ocean
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watershed
area of land drained by runoff
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aquifers
underground caverns and porous layers of rock in which groundwater is stored
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aquifer depletion
human removal of more groundwater than precipitation or melting snow recharges
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bottom-up processes
processes based on food webs that have producers at the first trophic level
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top-down processes (trophic cascade)
processes that regulate ecosystem function by trophic interactions, particularly from the highest trophic level
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abiotic environmental factors
solar radiation, atmosphere, climate, ocean, fire
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importance of solar radiation
- warms Earth and prevents absolute zero
- Powers biogeochemical cycles
- Photosynthesis
- Fuels represent solar energy
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Interactions of solar radiation
- less than one billionth hits Earth
- 30% reflected away immediately
- 23% runs hydrologic cycle
- 47% absorbed by atmosphere
- less than 1% drives wind and currents
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temperature and solar radiation
Earth's tilt, direction of rays, and deeper envelope of air influence temperature
tilt of Earth influences seasons
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atmosphere composition
oxygen - 21%
nitrogen- 78%
other gases- 1%
- Ar, CO2, Ne, He
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Functions of atmosphere
- shields UV rays
| - controls temperature
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wind and atmosphere
- winds result from different atmospheric pressures and Earth's rotation
- blows from high to low pressure
- rotation influences direction
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Winds
complex horizontal movements exhibited by the atmosphere
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Coriolis effect
tendency of moving air to be deflected from its path by Earth's rotation
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ocean currents
mass movements of surface ocean water produced by persistent prevailing winds blowing over the ocean
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gyres
circular ocean currents generated by prevailing winds
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El Niño Southern Oscillation (ENSO)
periodic warming of surface waters of the tropical eastern Pacific that alters both oceanic and atmospheric circulation patterns and results in unusual weather in area far from the tropics
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upwelling
process in which nutrients come to the surface with deeper, colder waters
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climate definition
average weather conditions ,plus extremes (records), that occur in a given place over a period of years
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rain shadows
dry lands on the sides of the mountains away from the prevailing wind
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microclimates
local variations in climate
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causes of microclimates
differences in elevation, steepness and direction of slopes > exposure to sunlight and prevailing winds
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wildfires
fires started by lightning
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effect of fires on organisms
- combustion frees mineral in dry organic matter
- removes plant cover and exposes soil
- causes increased soil erosion
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controlled burning
tool of ecological management in which the undergrowth and plant litter are deliberately burned under controlled conditions before they have accumulated to dangerous levels
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deforestation
clearance of large expanses of forest for agriculture or other uses
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ecosystem mangement
a conservation approach that emphasizes restoring and maintaining the quality of an entire ecosystem rather than the conservation of individual species
