Chapter 42: Ecosystems and Energy Flashcards
What do physical laws govern?
energy flow and chemical cycling in ecosystems?
What do energy and other limiting factors control?
primary production in ecosystems
How efficient is energy transfer between trophic levels typically?
10%
What do biological and geochemical processes cycle in ecosystems?
nutrients and water
What do restoration ecologists do?
return degraded ecosystems to a more natural state
What is an ecosystem?
the sum of all the organisms living within its boundaries and all the abiotic factors with which they interact
How does most energy enter the ecosystem as?
sunlight
What does the first law of thermodynamics state that?
energy cannot be created or destroyed but only transferred or transformed. Plants and other photosynthetic organisms convert solar energy to chemical energy but the total amount of energy does not change
What does the implication of the second law of thermodynamics state?
that energy conversions are inefficient. Some energy is always lost as heat
What are most gains or losses to ecosystems small compared to?
the amounts recycled within them
What are primary producers occupy?
the trophic level that supports all other plants
What are organisms in trophic levels above primary producers called?
heterotrophs
What eat primary producers?
primary consumers or herbivores
Who eat herbivores?
secondary consumers or carnivorres
Who eat other carnivores?
tertiary consumers or carnivores
What do detritivores or decomposers consume?
detritus which is non-living organic material
What do detrivores convert?
organic materials from all trophic levels to inorganic compounds usable by primary producers
What is primary production?
the amount of light energy converted to chemical energy by autotrophs in the ecosystem
What does the amount of photosynthetic production set?
the spending limit for the entire ecosystem’s energy budget
How much of the visible light that strikes photosynthetic organisms is converted to chemical energy?
1%
What is gross primary production?
the total primary production in an ecosystems (amount of light energy converted to chemical energy per unit time)
What is some of the energy that is converted through photosynthesis used for?
Cellular respiration (R)
What is net primary production?
the stored energy only available to consumers
What is standing crop?
the total biomass of photosynthetic autotrophs in an ecosystem
What is primary production in aquatic ecosystems affected by?
light and nutrient availability
What is a limiting nutrient?
the element that must be added for production to increase
What is a eutrophic lake?
a lake that is rich in nutrients and promotes the growth of primary production
What are the main factors controlling primary production in terrestrial ecosystems?
temperature and moisture
What is evapotranspiration?
the total amount of water transpired by plants evaporated from the landscape
What is secondary production?
the amount of chemical energy in consumer’s food that is converted to new biomass during a given period
What is trophic efficiency?
the percentage of production transferred from one trophic level to the next
What are biogeochimcal cycles?
nutrient cycles that contain both biotic and abiotic components?
What is evaporation?
as water is out from bodies of water through the addition of energy from the sun
What is precipitation?
the return of water to the Earth
What is transpiration?
the loss of water from plants
What is phosphorus mainly used for?
nucleic acids, phospholipids, and ATP
What is the only inorganic form which plants can absorb and use?
Phosphate or PO4(3-)
What are the primary processes by which carbon cycles between the atmosphere and terrestrial environments?
photosynthesis and respiration
What is the equation for photosynthesis?
6CO2 + 12H2O ———> C6H12O6 + 6O2 + 6H2O
What is the equation for respiration?
C6H12O6 + 6O2 + 6H2O —–> 6CO2 + 12H2O
What is adding significant amounts of additional CO2 to the atmosphere?
the burning of fossil fuels
What is global warming?
when CO2 in the atmosphere traps heat beneath the ozone layer resulting in rise in global temperatures
What is nitrogen a part of?
amino acids, proteins, and nucleic acids and is often a limiting plant nutrients
What is the main reservoir of nitrogen
atmosphere (80% N2), which is unusable by plants
What can plants use nitrogen in the form of?
ammonium (NH4+) and nitrate (NO3-)
What is nitrogen fixation?
the conversion of N2 by bacteria to a form that can be used by plants
What is nitrification?
the process by which ammonium (NH4+) Is converted to nitrate (NO3-) by bacteria
What is ammonification?
the decomposition of amino acids and wastes into NH4+
What is denitrification?
breaks down nitrates and releases nitrogen (N2) to the atmosphere
What is bioremediation?
the use of organisms, usually prokaryotes, fungi or plants to detoxify polluted ecosystems
What is bioaugmentation?
the introduction of desirable species that can add essential materials to a degraded ecosystem
