Energy Flow
Energy in an ecosystem originally comes from what source?
the Sun
A simple model showing one path of energy flow is called a:
a food chain
What happens to the 90% of energy NOT passed on?
It is lost as heat or used by the organism.
Define carrying capacity.
The maximum population an environment can support long‑term.
Predation is when:
One organism kills and eats another.
Organisms that make their own food are called what?
producers
A complex network of feeding relationships is called a:
a food web
A hawk that eats a snake that ate a mouse is a:
a tertiary consumer
When a population reaches carrying capacity, its size will:
Level off and fluctuate.
Competition happens when organisms fight for:
Limited resources.
Only about ___% of energy moves to the next trophic level.
10
In a food chain, what type of organism eats producers?
primary consumers
Why are there fewer top predators than producers?
Less energy is available at higher trophic levels.
Disease spreading faster in crowded populations is an example of:
density‑dependent factor
Mutualism is when:
Both organisms benefit.
Why does energy decrease as you move up an energy pyramid?
Most energy is lost as heat or used for life processes.
If a top predator is removed from a food web, what happens?
Populations below it become unbalanced (trophic cascade).
What does an energy pyramid show?
The amount of energy available at each trophic level.
A natural disaster affecting all organisms equally is:
density‑independent factor
Give two reasons animals group together.
Protection, finding food, saving energy, or increasing survival.
Which trophic level contains the MOST energy?
producers?
Explain why food webs are more stable than food chains.
They have multiple feeding pathways, so organisms have alternatives.
Explain why eating lower on the food chain is more energy‑efficient.
More energy is available at lower trophic levels.
Explain how limiting factors control population size.
They restrict growth by reducing resources or increasing mortality.
Explain how group behavior increases survival in predators AND prey.
Predators hunt more effectively; prey avoid predators more easily.