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