bio semester 1 concept energy flow through ecosystems

Source of all energy on Earth

All energy on Earth ultimately comes from the Sun.

Producers (Autotrophs)

Organisms that get energy from nonliving sources and make their own food.

Consumers (Heterotrophs)

Organisms that get energy by eating living or once-living organisms.

Photosynthesis

Process where producers use sunlight to make glucose from CO2 and H2O.

Photosynthesis Equation

6CO2 + 6H2O → C6H12O6 + 6O2

Photosynthetic Organisms

Plants and cyanobacteria

Chemosynthesis

Process where organisms use chemical energy (not sunlight) to make food.

Chemosynthesis Example

Deep-sea vent bacteria using sulfur or methane

How Consumers Get Energy

By eating organisms and releasing ATP through cellular respiration.

Herbivores

Consumers that eat only plants

Carnivores

Consumers that eat only animals

Omnivores

Consumers that eat both plants and animals

Detritivores (Decomposers)

Consumers that eat dead organisms and waste

Food Chain

Shows a single pathway of energy flow through trophic levels.

Trophic Levels

Levels of nourishment in a food chain.

Rule of 10

Only 10% of energy passes to the next trophic level; 90% is lost as heat.

Order of Trophic Levels

Producers → Primary → Secondary → Tertiary Consumers

Food Web

Shows multiple interconnected food chains.

Trophic Pyramids

Models showing energy, biomass, or number of organisms at each trophic level.

Energy Pyramid

Shows decreasing energy at higher trophic levels.

Numbers Pyramid

Shows fewer organisms at higher trophic levels.

Biomass Pyramid

Shows total mass of living matter at each trophic level.

Energy Pyramid Example

Grass (100%) → Grasshopper (10%) → Mouse (1%) → Owl (0.1%)