Glossary
10% Rule
An ecological principle stating that only about 10% of the energy from one trophic level is transferred to the next higher trophic level, with the remaining 90% lost primarily as heat.
Example:
If a field of grass contains 10,000 units of energy, the 10% Rule predicts that the rabbits eating the grass will only gain about 1,000 units of that energy.
Abiotic factors
The non-living physical and chemical components of an ecosystem.
Example:
Sunlight, water temperature, and soil pH are examples of abiotic factors that affect plant growth in a garden.
Biotic factors
The living or once-living components of an ecosystem.
Example:
The fish, algae, and bacteria in a pond are all biotic factors influencing its health.
Carnivores
Consumers that obtain energy by eating other animals.
Example:
A wolf is a carnivore that hunts and eats deer to acquire energy.
Cellular respiration
The process by which organisms break down glucose and other organic molecules to release usable chemical energy (ATP) for life processes.
Example:
Both a plant and an animal perform cellular respiration to convert the energy stored in glucose into a form their cells can utilize.
Chemical energy
Energy stored in the bonds of chemical compounds, such as glucose or ATP, that can be released through chemical reactions.
Example:
The food we eat contains chemical energy that our bodies convert into usable forms for movement and warmth.
Decomposers
Organisms, such as bacteria and fungi, that break down dead organic matter, recycling nutrients back into the ecosystem.
Example:
Fungi acting as decomposers break down a fallen tree, returning its stored carbon and other nutrients to the soil.
Entropy
A measure of the disorder or randomness in a system; it tends to increase in natural processes as energy transforms.
Example:
A perfectly organized room will naturally tend towards higher entropy over time as items are used and left out of place.
First Law of Thermodynamics
Also known as the law of conservation of energy, it states that energy cannot be created or destroyed, only transformed from one form to another.
Example:
When a solar panel converts sunlight into electricity, the First Law of Thermodynamics explains that the energy isn't lost, just changed form.
Herbivores
Primary consumers that obtain energy by consuming producers (plants).
Example:
A deer is a herbivore that gains energy by grazing on leaves and twigs.
Photosynthesis
The process by which producers use sunlight, water, and carbon dioxide to create glucose (chemical energy) and oxygen.
Example:
A tree performs photosynthesis to convert sunlight into the sugars it needs for growth and survival.
Producers
Organisms, primarily plants and algae, that convert solar energy into chemical energy through photosynthesis, forming the base of food chains.
Example:
In a grassland, the grasses are the producers, converting sunlight into usable energy for other organisms.
Second Law of Thermodynamics
States that during every energy transformation, some energy is converted into a less usable form, often heat, leading to an increase in entropy (disorder) in the universe.
Example:
When a car engine burns fuel, the Second Law of Thermodynamics explains why much of the chemical energy is lost as waste heat rather than being converted into useful motion.
Solar energy
The ultimate source of energy for almost all ecosystems on Earth, driving most ecological processes.
Example:
Plants use solar energy to grow, forming the base of nearly all food webs.
Thermal energy
Energy in the form of heat, which is the most disordered and least usable form of energy resulting from energy transformations.
Example:
When you exercise, your body converts chemical energy into kinetic energy, but much is lost as thermal energy, making you feel warm.
Trophic pyramid
A graphical representation illustrating the energy flow and biomass at different feeding levels within an ecosystem.
Example:
A trophic pyramid for an ocean ecosystem would show a vast base of phytoplankton supporting smaller populations of zooplankton, then fish, and finally top predators like sharks.