Ch. 55 Flashcards
An _______ consists of all the organisms living in an area as well as the abiotic factors with which they interact
ecosystem
Regardless of an ecosystem’s size, its dynamics involve two main processes: _______ and _______
energy flow and chemical cycling
The _______ states that energy cannot be created or destroyed, only transferred or transformed
first law of thermodynamics
Energy enters an ecosystem as _______, is conserved, and is lost from organisms as _______
solar radiation; heat
The _______ states that every exchange of energy increases the entropy of the universe
second law of thermodynamics
The _______ states that matter cannot be created or destroyed
law of conservation and mass
Ecosystems are _______, absorbing energy and mass and releasing heat and waste products
open systems: energy and nutrients can flow in and out of the cycle
_______ build molecules themselves using photosynthesis or chemosynthesis as an energy source to connect carbon together
Autotrophs
_______ depend on the biosynthetic output of other organisms
Heterotrophs
Primary producers are
autotrophs
primary consumers are
herbivores
Secondary consumers are
carnivores
tertiary consumers are
carnivores that feed on other carnivores
In marine and freshwater ecosystems, both _______ and _______ limit primary production
light and nutrients
_______ and _______ are the main detritivores
Prokaryotes and fungi
In most ecosystems, _______ is the amount of light energy converted to chemical bond energy by autotrophs during a given time period
primary production
Total primary production is known as the ecosystem’s _______
gross primary production (GPP)
GPP minus energy used by autotrophs for respiration (Ra) = _______
Net primary production (NPP)
- usually about half
primary production can be expressed as _______ or _______ (units)
energy or biomass
NPP is _______ in a given time period, not the total biomass of autotrophs
amount of new biomass added
A _______ is the element that must be added for production to increase in an area
limiting nutrient
_______ and _______ are the nutrients that most often limit marine production
Nitrogen and phosphorous
_______ of nutrient-rich waters in parts of the oceans contributes to regions of high primary production
Upwelling
explain what happens to fish due to eutrophication in lakes
1) nutrients promote growth of primary producers
2) detritivores break down all the dead producers and use up all dissolved oxygen
3) no more oxygen in water for fish so they die
Why should we use phosphate-free detergents when cleaning our clothes?
Phosphates in our detergent can lead to cyanobacterial growth in the water we dispose our laundry water into. This can have a major impact in that environment due to eutrophication
_______ is the most common limiting nutrient in terrestrial ecosystems
Nitrogen
_______ can also be a limiting nutrient, especially in older soils
Phosphorus
how do plants obtain nitrogen?
mutualistic relationship with nitrogen-fixing bacteria
How do plants obtain phosphorus?
mutualistic relationship with mycorrhizal fungi
Secondary production of an ecosystem is the amount of _______ converted to new biomass during a given period of time
chemical energy in food
birds and mammals: fishes: insects and microorganisms
- efficiency of secondary production
insects and microorganisms > fishes > birds and mammals
_______ is the percentage of production transferred from one trophic level to the next
Trophic efficiency
In a _______, each tier represents the dry mass of all organisms in one trophic level
biomass pyramid
Compare an oceans biomass pyramid with land
oceans ratio of primary producers: primary consumers is switched
- Certain aquatic ecosystems have inverted biomass pyramids: Producers (phytoplankton) are consumed so quickly that they are outweighed by primary consumers
The rate of decomposition is controlled by _______, _______, and _______
temperature, moisture, and nutrient availability
Rapid decomposition results in relatively _______ levels of nutrients in the soil
low
Explain the water cycle
water moves by
1) evaporation
2) transpiration
3) condensation
4) precipitation
5) overall movement through surface and groundwater
Explain the Carbon Cycle
1) Photosynthetic organisms convert CO2 to organic molecules that are consumed by heterotrophs, then exhaled
2) Carbon reservoirs include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, the atmosphere, and sedimentary rocks
explain the Nitrogen Cycle
1) nitrogen reserve in atmosphere (N2)
2) converted to NH4+ or NO3- by bacteria
3) used by plants
4) animals get it through plants
5) converted back
Organic nitrogen is decomposed to NH4+ by _______, and NH4+ is decomposed to NO3– by nitrification
ammonification
_______ converts NO3– back to N2
Denitrification
Explain the Phosphorus Cycle
1) The largest reservoirs are sedimentary rocks of marine origin, soil, the oceans, and organisms
2) Weathering of rocks releases phosphate into the soil, and it reaches aquatic systems through leaching
