Food Chains and Food Webs
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50 free Food Chains and Food Webs trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Every living thing has to eat, and what it eats decides where it sits in nature. A food chain traces one line of that story, from a green plant to the animal that grazes on it to the hunter that catches the grazer. A food web is what you get when many chains cross, which is how real ecosystems work. This quiz covers both. It starts with who eats what: familiar animals and their surprising diets, in forests, grasslands, rivers and seas. It moves on to the science taught in school, including where the energy comes from, why so little of it reaches the top, the words biologists use for each feeding role, and what happens to a whole web when one link is added or removed. It is written for students revising a food chain or food web unit, teachers who want ready-made review questions, and anyone curious about how nature feeds itself. The questions run from easy to challenging, and every answer comes with a short explanation.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Blue whales, the largest animals ever known, feed almost entirely on which swarming crustaceans?
Krill
Krill make up almost the whole diet of the blue whale, which lunges into a swarm at speed with its mouth gaping up to 80 degrees and strains them from the water.
Q 02Giant pandas belong to the meat-eating order Carnivora, yet about 99% of their diet is which plant?
Bamboo
Bamboo gives a giant panda little energy, because the animal still has the short, straight gut of a carnivore and so has to eat enormous amounts of it.
Q 03Which bog plant, native only to the Carolinas, flips the food chain by snapping shut on insects?
Venus flytrap
The Venus flytrap shuts only when two of its trigger hairs are touched within about twenty seconds, a check that stops it wasting effort on raindrops.
Q 04Which mammal guards Pacific kelp forests by eating the sea urchins that graze them bare?
Sea otters
Sea otters eat so many sea urchins that their teeth and bones can be stained purple, and where they vanish the urchins can mow whole kelp forests down.
Q 05Which predators, back in Yellowstone since 1995 after nearly seventy years away, prey mainly on elk?
Gray wolves
Gray wolves were released in the Lamar Valley, and as their packs grew the elk herds shrank, easing the browsing pressure on the willows and aspens.
Q 06Which ocean predator, hunted by nothing itself, flips great white sharks over to eat their livers?
Killer whale
The killer whale rolls a great white onto its back, which sends the shark into a paralysis called tonic immobility, and then goes for the liver.
Q 07Which scavenging birds have stomach acid that can destroy the anthrax and botulism in rotten meat?
Vultures
Vultures digest putrid meat in stomach acid of about pH 1, which lets them clean up infected carcasses that would be lethal to other scavengers.
Q 08Owls swallow mice whole and later cough up the fur and bones as what, often dissected in school?
Pellets
Pellets hold the fur, bones and teeth an owl cannot digest, so picking one apart reveals exactly what the bird has been feeding on without harming it.
Q 09Which popular pet is an obligate carnivore, needing meat because it cannot make enough taurine?
Domestic cat
The domestic cat cannot make enough taurine, and heart disease was common in cats fed commercial diets until a 1987 study traced it to a lack of that nutrient.
Q 10Koalas sleep up to twenty hours a day on a diet of the low-energy leaves of which tree?
Eucalyptus
Eucalyptus leaves are low in calories and contain toxins that put off most other mammals, which leaves koalas with a food supply few rivals want.
Q 11Almost every food chain on Earth, from pond to coral reef, gets its energy originally from where?
The Sun
The Sun powers almost every food chain, yet plants capture only about one percent of the light that reaches them, and all animal life runs on that sliver.
Q 12Which name do ecologists give plants and algae, which start a food chain by making their own food?
Producers
Producers build their own food from light, air and water, so every animal in a food chain, even a lion that never touches a leaf, depends on them in the end.
Q 13Which food web role do soil bacteria fill by breaking dead plants and animals down into nutrients?
Decomposers
Decomposers return the nutrients locked in dead leaves, wood and bodies to the soil, where roots can take them up again and the cycle restarts.
Q 21Which drifting organisms, too small to see, feed most ocean life and make half of Earth's oxygen?
Phytoplankton
Phytoplankton do about half of all the planet's food-making despite adding up to only about 1% of its plant mass, and nearly every ocean food web rests on them.
Q 22Which toxic metal climbs ocean food chains, which is why pregnant women are told to avoid swordfish?
Mercury
Mercury is taken up by algae and handed on with every meal, so shark meat can hold more than ten times the concentration found in herring.
Q 23Which insecticide, building up in food chains, thinned bald eagle eggshells until a 1972 US ban?
DDT
DDT built up in the birds' prey, and their eggshells grew so thin that they often cracked before the chicks could hatch.
Q 14Which term describes a tiger, a saltwater crocodile or any hunter at the top of its food chain?
Apex predator
Apex predator is the label for a hunter with few or no natural enemies, and by keeping prey and smaller hunters in check such animals can reshape a whole ecosystem.
Q 15Which process lets green plants turn light, water and carbon dioxide into sugar and oxygen?
Photosynthesis
Photosynthesis was discovered in 1779 by Jan Ingenhousz, who showed that plants need light, and not just soil and water, in order to grow.
Q 16On average, about what share of the energy in one link of a food chain passes on to the next link?
10%
Only about 10% of the energy moves up each time, which is why a field of grass can feed many rabbits but those rabbits can feed only a few foxes.
Q 17In a food chain drawn as grass, then rabbit, then fox, each arrow stands for which phrase?
Is eaten by
Is eaten by is how to read every arrow, because the arrowhead follows the energy as it leaves the food and enters the animal that swallows it.
Q 18Which shape do ecologists use to show each step of a food chain holding less energy than the last?
A pyramid
A pyramid fits because the broad base of plants supports ever narrower layers of animals above, and one drawn for energy can never be turned upside down.
Q 19Most energy an animal eats never reaches the next link in a food chain, leaving mainly as what?
Heat
Heat carries the energy away, given off as the animal's cells burn food to keep it moving, growing and alive, so it can never be passed up the chain.
Q 20In the food chain grass, grasshopper, frog, the insect-eating frog is which kind of consumer?
Secondary
Secondary is the label for any animal that eats plant-eaters, and a snake that then swallowed the frog would sit one rung further up.
Q 24Monarch caterpillars eat only which plant, storing its toxins to make themselves poisonous to birds?
Milkweed
Milkweed sap is laced with heart poisons that the caterpillars store in their bodies, and their bright colors warn hunters of the foul taste.
Q 25Which insects, sacred in ancient Egypt, steer by the Milky Way while rolling away a ball of food?
Dung beetles
Dung beetles bury and eat the droppings of larger animals, which returns nutrients to the soil, and one African species holds its course at night by the galaxy's glow.
Q 26Which kingdom of life does most of the work of rotting a fallen tree on the forest floor?
Fungi
Fungi digest their food outside their bodies, threading fine hyphae deep into dead wood that bacteria can only work on from the surface.
Q 27Which soil animals, the subject of Charles Darwin's last book, drag dead leaves into burrows to eat?
Earthworms
Earthworms so fascinated Darwin that he made a trip to Stonehenge to see how far their castings had buried its fallen stones.
Q 28Grizzly bears have a carnivore's gut, but a diet of nuts, tubers, moths and meat makes them what?
Omnivores
Omnivores eat both plants and animals, and in Yellowstone a grizzly's menu is mostly pine nuts, tubers, grasses, rodents and moths.
Q 29Which bird of prey, the fastest animal on Earth in a dive, feeds almost entirely on other birds?
Peregrine falcon
The peregrine falcon strikes its prey in mid-air after a dive of more than 320 km/h, and its menu runs from pigeons and ducks to songbirds and parrots.
Q 30Which reef fish scrape algae off coral rock and excrete it as the white sand of tropical beaches?
Parrotfish
Parrotfish grind up the rock along with the algae between a second set of teeth in the throat, and the sand they pass helps to build beaches and small islands.