Lesson 22: Ecosystems capture energy and cycle chemicals

Exam 4

Characteristics of energy flow in ecosystems

Nutrients recycled in ecosystem

Energy never recycled

Define the first law of thermodynamics

energy not created or destroyed

energy changes form

Describe the second law of thermodynamics

energy conversion to heat or biomass

Define trophic level

feeding groups position in food chain

What makes up level one trophic level?

autotrophs/primary producers

energy from sun

synthesize organic compounds

What makes up level two trophic level?

herbivores

energy from level one

What makes up level three trophic level?

primary carnivores

energy from level two

What makes up level four trophic level?

secondary carnivores

energy from level three

What levels of the trophic level are consumers?

level 2, 3, 4

Where do detritivores and decomposers get their energy?

from dead organic material

Energetics of trophic level

productivity

gross primary productivity

respiration

net primary productivity

Define productivity

all organism in trophic level synthesize new organic matter

Define primary productivity

available energy for ecosystem

Define secondary productivity

available for next level

Define gross primary productivity (GPP)

productivity of primary producers

Define respiration

metabolic needs

Define net primary productivity (NPP)

energy left over after primary producers becomes available for consumption for the next trophic level

What are secondary producers?

heterotrophs

Describe ingested net primary productivity

metabolic needs met leads to heat energy leaving from respiration or waste or converted to biomass

What does secondary production produce?

biomass which is available for the next energy level

What is the 10% rule?

chemical energy transferred to next trophic level

Pyramid types

energy flow

biomass

numbers

Which pyramid can never be inverted? and why?

energy flow due to 10% rule

Which pyramid can be inverted?

biomass because it looks at the weight of things

What is the top-down effect?

upper trophic level impacts 2 or more lower levels

What is the top-down effect also called?

trophic cascade

What causes the trophic cascade?

predators regulating prey

What is the bottom-up effect?

producers influence above trophic levels

Progression of trophic levels in bottom-up effect

primary producers

support herbivores

herbivores reach critical density

support carnivores

Describe the bottom up effect

Primary producers → low biomass → increase to critical density

Support introduction of herbivores → producer biomass decreases

Herbivores reach critical density → support carnivores

Carnivore biomass increase → primary herbivore biomass decreases → primary producers increase

Steps of the water cycle

evaporation

transpiration

precipitation

percolation

Define evaporation

water converted from its liquid form from bodies of water into gaseous form in the atmosphere

Define transpiration

water exits from the surfaces of plant

Define condensation

water vapor in the air is converted into liquid water

Define precipitation

water returned from the atmosphere to the surface of earth in the forms of rain, snow, sleet, hail, etc

Define percolation

 water travels downward through the spaces of rocks and soil particles

Carbon cycle steps

Carbon fixation

Respiration

Decomposition

Methane production

Atmospheric chemicals

Carbon dioxide

Nitrogen

Phosphorus

Carbon dioxide significance

most abundant carbon containing compound in abiotic environments

Nitrogen characteristics

not readily usable from atmosphere and must be converted into usable form by bacteria

Nitrogen cycle steps

Nitrification

Nitrogen fixation

Denitrification

Define nitrification

conversion of ammonium or ammonia into nitrates

Define nitrogen fixation

conversion of atmospheric nitrogen into ammonia by prokaryotic organisms

Define denitrification

conversion of nitrates to nitrogen gas, returning nitrogen to the atmosphere

Phosphorus cycle characteristics

No atmospheric phase

Weathering

Decomposition

What is the island biogeographical principle?

species richness is a result of…

island size

distance of island from mainland

equilibrium between colonization and extinction