Food Chain Basics
What do we call the path that shows how energy moves from one living thing to another?
A food chain
What is a living thing that hunts and eats another organism called?
A predator
What is the main source of energy for most ecosystems?
The Sun
Living things and the nonliving parts of their environment interacting.
What is an ecosystem?
A caterpillar eats a leaf. Is the caterpillar a producer or consumer?
A consumer.
What is an organism called when it makes its own food, usually using sunlight?
A producer
What do we call an animal that is hunted and eaten by another animal?
Prey
Which organism in a food chain usually receives energy directly from the Sun?
A producer, such as a plant.
What might happen to grass if the rabbit population decreases?
Grass may increase because fewer rabbits are eating it.
A hawk eats a snake that ate a mouse that ate seeds. Which organism is the producer?
The plant that produced the seeds.
In the chain grass → rabbit → fox, which organism is the primary consumer?
The rabbit
What role do fungi and many bacteria play in an ecosystem?
Decomposers; they break down dead organisms and waste.
When a rabbit eats grass, where does the rabbit get its energy?
From the food it eats—the grass.
If a disease greatly reduces the mouse population, name one animal that might have less food available.
An animal that eats mice, such as an owl, hawk, or snake.
In a food web, arrows point from the grass to the rabbit. What does the arrow represent?
The direction energy moves—from the grass to the rabbit.
Why do most food chains begin with plants or other producers?
They capture energy from sunlight and make their own food.
How is a food web different from a food chain?
A food web shows many connected feeding relationships, while a food chain shows one pathway.
Why is less energy available to organisms at higher levels of a food chain?
Organisms use much of the energy for life processes, and some energy is released as heat; only a portion passes to the next level.
How could removing a predator affect the population of its prey?
The prey population may increase, although other factors can affect the outcome.
A pesticide reduces the insect population. Predict one possible effect on frogs and explain why.
The frog population may decrease because fewer insects are available for food.
A grasshopper eats grass, and a frog eats the grasshopper. Identify the producer, primary consumer, and secondary consumer.
Grass = producer; grasshopper = primary consumer; frog = secondary co
An owl eats mice and snakes, while a snake eats mice. What does this tell you about the owl’s and snake’s feeding relationships?
They share a food source, and their feeding relationships are interconnected in the food web.
In the chain Sun → grass → grasshopper → frog → snake, explain how energy reaches the snake.
Sunlight is captured by grass, the grasshopper eats the grass, the frog eats the grasshopper, and the snake eats the frog.
A drought reduces the amount of grass in an ecosystem. Explain two possible effects on other organisms in the food web.
Plant-eating animals may have less food and decrease or move away; predators may then have less prey available.
A food web includes plants, insects, frogs, snakes, and hawks. A disease nearly eliminates the frogs. Explain how this change could affect at least two other populations.
Insects may increase because fewer frogs eat them; snakes may decrease because they have fewer frogs to eat. Other effects depend on the rest of the food web.