Energy Flow & Ecological Relationships

Vocabulary flashcards that summarize core terms related to solar energy input, trophic levels, energy transfer, food chains, food webs, ecological pyramids, and factors affecting energy efficiency in biological systems.

Sun (Solar Input)

Principal source of light and heat energy for almost all biological systems.

Photosynthetic Organisms

Plants and some bacteria that trap light energy and convert it into chemical energy through photosynthesis.

Chemical Energy

Stored energy in the bonds of molecules such as glucose, produced during photosynthesis and passed along food chains.

Energy Flow (Non-cyclical)

Movement of energy through a food chain that is not recycled; energy is eventually lost as heat to the environment.

Heterotrophic Organisms

Organisms that obtain energy by consuming other organisms rather than producing their own food.

Food Chain

Linear sequence showing energy flow from a producer to successive consumers, indicated by arrows pointing toward the eater.

Trophic Level

Feeding level in a food chain or web (e.g., producer, primary consumer, secondary consumer).

Producer

Photosynthetic organism at the base of a food chain that makes food for other organisms.

Primary Consumer (Herbivore)

Animal that eats producers and occupies the second trophic level.

Secondary Consumer

Carnivore or omnivore that eats primary consumers and occupies the third trophic level.

Tertiary Consumer

Predator that eats secondary consumers and occupies the fourth trophic level.

Decomposer

Organism (e.g., bacteria, fungi) that breaks down dead material, returning nutrients to the environment.

Energy Loss (Respiration)

Heat energy released when organisms break down food molecules during cellular respiration.

Energy Loss (Movement)

Energy expended when organisms move to find food, mates, or escape predators.

Thermoregulation

Process by which warm-blooded animals maintain constant body temperature, losing heat to the environment.

Excretion

Loss of energy in faeces and urine produced by animals.

Indigestible Material

Portions of food (e.g., roots, cellulose) not consumed or not digested, leading to energy loss between trophic levels.

10 Percent Rule

On average, only about 10 % of the energy at one trophic level is transferred to the next level.

Food Web

Network of interconnected food chains showing multiple feeding relationships within an ecosystem.

Ecological Pyramid

Diagram representing relative numbers, biomass, or energy at each trophic level of a food chain.

Pyramid of Numbers

Ecological pyramid showing the count of individual organisms at each trophic level.

Pyramid of Biomass

Ecological pyramid displaying the dry mass of organisms at each trophic level.

Pyramid of Energy

Ecological pyramid that illustrates the amount of energy transferred per unit area and time at each trophic level.

Biomass

Total dry mass of living material in organisms at a particular trophic level or area.

Energy Efficiency (Food Chains)

Proportion of original solar energy or producer energy that reaches higher trophic levels; higher in shorter chains.

Short Food Chain

Food chain with few trophic levels, resulting in less cumulative energy loss and greater efficiency for the top consumer.

Endotherm (Warm-blooded Animal)

Animal that generates internal heat to maintain body temperature (e.g., birds, mammals).

Arrow Direction (Food Chains)

Symbol in a food chain or web that points from the food source toward the organism that consumes it, indicating energy flow.

Energy Capture Limitations (Plants)

Reasons plants do not use all incident light: reflection, wrong wavelength, light passing through leaves, or missing leaves.

Conservation of Energy in Diet

Idea that feeding humans as primary consumers (vegetarians) can make more energy available than feeding them animal products.