Food Webs and Energy — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. If a disease killed all the rabbits, the foxes that eat them would have less food.
Reducing prey populations decreases available food for predators, causing predator populations to decline too.
2. Removing one species from a food web can affect many other species.
Food webs are interconnected. Removing one species ripples through the web, affecting populations at multiple levels.
3. An energy pyramid shows that producers have the most energy in an ecosystem.
An energy pyramid has producers at the base (most energy) and top predators at the narrow top (least energy).
4. Carnivores eat only meat.
Carnivores are animals that eat only other animals (meat). Examples: lions, wolves, eagles.
5. A bear that eats fish and berries is classified as an omnivore.
Bears eat both plants (berries) and animals (fish), making them omnivores.
6. Algae in a pond food web serve as producers.
Algae photosynthesize like plants, producing food energy that forms the base of aquatic food webs.
7. Earthworms help decompose dead leaves and return nutrients to the soil.
Earthworms are decomposers that break down organic matter and release nutrients back into the soil.
8. When a predator population grows too large, its prey population shrinks.
More predators eat more prey, reducing the prey population — a classic predator-prey cycle.
9. The arrows in a food chain point in the direction that energy flows.
Arrows in food chains show energy transfer direction: from the organism being eaten to the organism eating it.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
herbivore
→ eats only plants
breaks down dead matter
carnivore
→ eats only animals
eats only plants
omnivore
→ eats both plants and animals
eats only animals
decomposer
→ breaks down dead matter
eats both plants and animals
Herbivore → eats only plants; carnivore → eats only animals; omnivore → eats both; decomposer → breaks down dead matter.