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%
