Bio Unit 10

Energy Flow in Ecosystems

Energy enters ecosystems as sunlight, is converted to chemical energy by autotrophs, transferred through food chains, and lost as heat.

Producers (Autotrophs)

Organisms that convert light (photoautotrophs) or chemical energy (chemoautotrophs) into organic molecules.

Consumers (Heterotrophs)

Organisms that obtain energy by feeding on other organisms (herbivores, carnivores, omnivores).

Primary Production

Energy conversion by autotrophs.

Secondary Production

Biomass accumulation by consumers.

Decomposers

Organisms (fungi, bacteria) that break down dead organic matter, recycling nutrients into the ecosystem.

Detritivores

Heterotrophs (e.g., earthworms, millipedes) that consume detritus (dead organic material) and contribute to decomposition.

Energy Loss in Food Chains

Only ~10% of energy is transferred between trophic levels due to respiration, heat loss, and inefficiencies in digestion.

Trophic Levels

The hierarchical levels in a food chain: producers to primary consumers to secondary consumers to tertiary consumers.

Food Webs

Interconnected food chains that show complex feeding relationships in an ecosystem.

Energy Pyramids

Graphical representations showing energy loss at each trophic level, limiting the number of trophic levels.

Carbon Cycle

The movement of carbon through photosynthesis, respiration, decomposition, and combustion.

Carbon Sinks

Natural reservoirs that store carbon, such as forests, oceans, and soil.

Carbon Sources

Processes or locations that release carbon dioxide, such as respiration, decomposition, and fossil fuel combustion.

Photosynthesis in Carbon Cycle

Plants absorb CO2 from the atmosphere and use it to produce glucose via photosynthesis.

Respiration in Carbon Cycle

All organisms release CO2 back into the atmosphere through cellular respiration.

Decomposition in Carbon Cycle

Detritivores and decomposers break down dead organisms, returning CO2 to the atmosphere and nutrients to the soil.

Fossil Fuels and the Carbon Cycle

Burning of coal, oil, and gas releases long-stored carbon into the atmosphere, contributing to climate change.

Keeling Curve

A graph showing the increase in atmospheric CO2 levels over time, driven by human activities.

Greenhouse Effect

CO2 and other greenhouse gases trap heat in the Earth's atmosphere, leading to global warming.

Carbon Footprint

The total amount of CO2 emissions produced by an individual, organization, or country.