lesson 22 Flashcards
(37 cards)
What does ecosystem ecology study?
How species interact with the physical environment to obtain resources.
What are the two major components of an ecosystem
Biotic (living) and abiotic (nonliving) components.
What is the ultimate energy source for most ecosystems?
solar energy
What are biogeochemical cycles
Cycles where nutrients move between living and nonliving parts of the ecosystem.
What processes cycle water through the environment?
Evaporation, transpiration, condensation, precipitation, and groundwater flow.
What is an aquifer
A permeable underground layer where groundwater is stored.
Why is carbon important for life
Carbon atoms form the backbone of all organic compounds.
What is carbon fixation?
The process where plants use carbon dioxide to synthesize organic compounds during photosynthesis.
What processes return carbon to the atmosphere?
Respiration, decomposition, methane production, and fossil fuel burning.
Why is nitrogen essential for organisms?
Needed for proteins and nucleic acids.
Why can’t plants and animals use nitrogen gas directly?
They can only use ammonium or nitrate, not atmospheric nitrogen
What is nitrogen fixation?
Conversion of nitrogen gas into ammonia by prokaryotes.
What is denitrification?
The process that returns nitrogen gas to the atmosphere under anaerobic conditions.
Why is phosphorus cycling unique
It has no gaseous phase.
How is phosphorus made available to plants?
Released by weathering of rocks into the soil.
What are common limiting nutrients in ecosystems
Nitrogen and phosphorus
What limits phytoplankton growth in oceans
Often the availability of iron from wind-blown dust.
Does energy recycle in ecosystems
No, energy flows one way and is not recycled
What does the first law of thermodynamics state
Energy cannot be created or destroyed, only transformed
What does the second law of thermodynamics state
Energy conversions produce heat energy, which living organisms cannot use for cellular needs.
What is a trophic level?
A feeding level in an ecosystem.
Who are primary producers?
Autotrophs, mostly photoautotrophs that use solar energy to make organic compounds
What are primary consumers
herbivores that feed on primary producers.
What are primary carnivores
Animals that feed on herbivores.
