21.1 - Energy Flow

ecosystem

sum of all interactions between biotic and abiotic factors in environment - 2 general types aquatic and terrestrial , which support diverse communities of organisms and energy flow.

biomes

large ecological areas on the Earth's surface, with distinct climates and specific plant and animal communities.

how are terrestrial biomes categorised

annual rainfall and temperature

biotic components in ecosystem

living organisms including plants, animals, fungi, and microbes 

abiotic components of ecosystems

non-living chemical and physical factors that affect ecosystems, such as sunlight, water, air, and minerals.

why is the chemical and physical environment a fundamental component of ecosystems

determines the amount of energy and types of nutrients available to rest of ecosystem = organisms that can take up energy and nutrients from surrounding environment forms basis

some key nutrients for living organisms

nitrogen, potassium and phosphorus 

trophic levels

different levels in a food chain that classify organisms based on their source of energy, including producers, consumers, and decomposers.

trophic level 1

producers - use photosynthesis to make their own food

trophic level 2

primary consumers - organisms that consume producers, mainly herbivores.

trophic level 3

secondary consumers - organisms that eat primary consumers, including carnivores and omnivores.

trophic level 4

tertiary consumer - top predator

detritivores and decomposers 

consume dead organisms = transfer matter back to earth to later be taken up by different primary producers

why is energy transformation up the food chain inefficient

Energy is lost as heat during each transfer, typically only about 10% is passed to the next trophic level.

net primary production

the amount of carbon remaining in plants after respiration - used to determine the amount of carbon fixed in ecosystem

• GPP - respiration

gross primary production GPP

total amount of carbon that gets fixed by primary producers

where is NPP higher and lower

• highest - tropics bc of warm temps and lots of moisture to perform primary production

• lowest - desert and high latitudes - limited moisture and extreme temperatures too low for primary productivity to be high

why is NPP higher in terrestrial than aquatic and higher in northern hemisphere

• in oceans phytoplankton and algae are more dispersed

• northern hemisphere has larger SA than south

why is energy described as flowing through ecosystems while nutrients as cycling

• energy can’t be reused - enters from sun transfers between organisms as food and eventually lost as heat

• nutrients are reused and recycled = moves repeatedly between organisms and environment

where do organisms het nutrients

• heterophs - consuming other organisms

• autotrophs - from soil, atmosphere and water

how do nutrients return to surrounding ecosystem

through gas exchange, urination defecation and decomposition

carbon cycle

autotrophs fix atmospheric CO2 via photosynthesis. all other organisms get carbon from consuming either autotrophs or organisms that ate those plants. Once organisms incorporate carbon is then either breathed out through respiration or returned to the soil through decomposition.

1st law of thermodynamics

Energy cannot be created or destroyed, only transformed from one form to another.

how is the 1st law demonstrated in food webs 

energy in organisms comes from previous trophic levels:

• Producers convert solar energy into chemical energy through photosynthesis.

• Consumers eat producers or other consumers, transferring that energy.

• Although energy changes forms, the total amount of energy remains constant