Energy Basics
What is the primary source of energy for most ecosystems on Earth?
The Sun
What type of organism is at the base of every food chain?
Producers
What is the term for each step in a food chain or food web?
Trophic level
What process in the water cycle involves water vapor cooling and changing into liquid droplets?
Condensation
In the nitrogen cycle, what process converts ammonia in the soil into nitrate ions that plants can absorb?
Nitrification
What term describes organisms that can make their own food from sunlight or chemicals?
Autotrophs
Which type of consumer only eats plants?
Herbivore
About what percentage of energy is transferred from one trophic level to the next?
Approximately 10%
Name one process in the carbon cycle that releases carbon dioxide into the atmosphere.
Respiration or combustion
Which cycle does not include an atmospheric component?
Phosphorus cycle
In what form is energy stored in plants?
Chemical energy in the form of glucose
What do you call an organism that breaks down dead matter?
Decomposer
What type of diagram shows the flow of energy between organisms in an ecosystem?
An energy pyramid
Which cycle involves nitrogen-fixing bacteria converting nitrogen gas into forms usable by plants?
Nitrogen cycle
What process in the nitrogen cycle converts nitrate back into nitrogen gas?
Denitrification
ame the process by which green plants convert sunlight into energy.
Photosynthesis
Name an example of a primary consumer in a grassland ecosystem.
A rabbit, zebra, wildebeest, insects.
What kind of organism is both a secondary and tertiary consumer?
Omnivore (depending on its diet)
In the phosphorus cycle, what natural process releases phosphorus into the soil?
Weathering of rocks
What form of nitrogen is most easily absorbed by plants?
Nitrate (NO₃⁻)
What is the law that states energy cannot be created or destroyed, only transformed?
The Law of Conservation of Energy
What is an apex predator?
An animal at the top of the food chain with no natural predators
What is the difference between a food chain and a food web?
A food chain shows a single path of energy flow, while a food web shows multiple interconnected food chains.
What is the main role of decomposers in the nutrient cycles?
They break down dead matter, returning nutrients to the soil.
How does burning fossil fuels contribute to global warming in terms of the carbon cycle?
It releases excess carbon dioxide (CO₂) into the atmosphere, trapping heat and enhancing the greenhouse effect.