CH BIO 38B EXtended Veison!

Energy flow direction

Energy moves in one direction from the sun to the consumers.

Energy transfer percentage

Only about 10% of energy at one trophic level is available to the next.

Ultimate energy source for ecosystems

Sunlight.

Net primary production

Energy trapped and stored by producers that consumers can eat.

Trophic level definition

An organism’s position in the food chain.

Producers

Organisms that convert inorganic energy (usually sunlight) into organic molecules; example: plants or algae.

Primary consumers

Herbivores that eat producers; example: grasshoppers or deer.

Secondary consumers

Carnivores that eat primary consumers; example: mice or frogs.

Tertiary consumers

Carnivores that eat secondary consumers; example: snakes or hawks.

Detritivores

Consumers that eat dead organic matter; example: earthworms or millipedes.

Decomposers

Organisms that chemically break down organic matter; example: fungi and bacteria.

Biomagnification

Increase in toxin concentration at higher trophic levels.

Pollutant characteristics allowing biomagnification

Fat-soluble and not easily degraded.

Example of biomagnification

Mercury buildup in tuna or eagles.

Why top predators are most affected

They consume many contaminated organisms, causing the highest toxin accumulation.

Carbon cycle reservoir

The atmosphere is the main inorganic carbon reservoir.

Carbon cycle: photosynthesis

Producers use inorganic carbon during photosynthesis to make organic molecules.

Carbon cycle: respiration

Organisms release carbon during cellular respiration.

Nitrogen importance

Component of proteins and nucleic acids.

Nitrogen reservoir

The atmosphere is the main inorganic nitrogen reservoir.

Nitrogen fixation

Process by which microbes convert atmospheric nitrogen (N₂) to ammonium.

Nitrification

Process converting ammonium to nitrate by nitrifying bacteria.

Denitrification

Process returning nitrogen to the atmosphere by denitrifying bacteria.

Phosphorus importance

Component of nucleic acids, ATP, and phospholipids.

Phosphorus reservoir

Phosphate-rich rocks.

Phosphorus enters soil

Phosphate enters soil as rocks weather.

Phosphorus return to soil

Decomposers return phosphorus to the soil.

Cycle without atmospheric component

The phosphorus cycle.

Eutrophication

Excess nutrient enrichment causing algal blooms and oxygen depletion.

Eutrophication steps

1. Excess nutrients enter water. 2. Algal bloom occurs. 3. Algae die and sink. 4. Decomposers break them down using oxygen. 5. Oxygen drops, causing fish deaths and dead zones.

Oligotrophic lake characteristics

Clear water, low nutrients, high oxygen, low productivity.

Eutrophic lake characteristics

High nutrients, algal blooms, murky water, low oxygen (especially at depth), high productivity, often supports fewer fish due to oxygen depletion.

Effect of removing decomposers

Nutrients stop cycling; dead matter accumulates; producers lack nutrients; ecosystem collapses.

Primary consumer in food chain

Grasshopper.

Tertiary consumer in food chain

Snake.

Energy reaching hawk from 10,000 calories of plants

Approximately 1 calorie.

Effect of energy loss on trophic levels

Fewer individuals occur at higher trophic levels because energy decreases greatly at each transfer.