Food Chains & Webs
What do all food chains start with?
A producer.
What name is given to organisms that use sunlight to make their own food?
Producers
What kind of pollution often harms fish and other aquatic life when it builds up in rivers?
Plastic waste.
What is a predator?
An organism that hunts and eats other animals.
What might happen to a pond food web if a chemical spill kills all the algae?
Primary consumers like tadpoles would have no food and their numbers would decline, affecting predators like frogs and birds.
In a pond ecosystem, algae are eaten by tadpoles. What role do the algae play?
They are producers.
Give an example of a first-order consumer in an Australian ecosystem.
Kangaroo eating grass
Suggest one action humans could take to reduce water pollution.
Reduce single-use plastics, improve recycling, or clean up waterways.
Give an example of a prey animal in Australia.
A wallaby.
How could a drought affect animals in a grassland food web?
Plants may die or grow less, reducing food for herbivores and ultimately affecting predators.
In a grassland, grass → grasshopper → frog → snake. Which organism is the secondary consumer?
The frog.
Why are decomposers like fungi important in ecosystems?
They recycle nutrients by breaking down dead organisms and waste.
If too many herbivores are hunted in an ecosystem, how might this affect predators?
Predator populations may decline due to less available food.
Why do predators usually have smaller populations than their prey?
Because there is less energy available at higher levels of the food chain, so fewer predators can be supported.
If a new predator is introduced into a forest, what is likely to happen to prey species?
Prey numbers may decrease, and this could also affect other predators and plants in the ecosystem.
Describe one key difference between a food chain and a food web.
A food chain shows a single energy pathway, while a food web shows many interconnected energy pathways.
Give an example of an omnivore and explain why it fits this role.
A magpie, because it eats insects (animals) and seeds (plants).
If a population of feral cats increases in a bushland, what could happen to small native mammals and the plants they feed on?
Small mammal numbers would decrease, and plants may increase because fewer animals eat them.
Explain how a decline in a prey population can affect predator populations.
Predators may struggle to find enough food, leading to a decline in their numbers.
Explain how urbanisation can change food webs.
Natural habitats are destroyed, some species are lost, and food sources are altered, causing shifts in populations throughout the food web.
Predict what might happen if all insects in a forest food web were removed.
Birds and small mammals that feed on insects would decline, and predators of those animals would also be affected.
If decomposers were removed from a rainforest ecosystem, what would be two major effects?
Dead matter would pile up, and plants would lack recycled nutrients for growth.
Give two long-term consequences of deforestation on biodiversity.
Loss of habitat for animals and reduction in plant species diversit
Describe one way prey animals have adapted to avoid being eaten.
Some prey have camouflage, speed, or defensive behaviors like hiding or herding to escape predators.
Describe one long-term consequence of climate change on marine food webs.
Warmer ocean temperatures can reduce plankton populations, which affects fish, seabirds, and marine mammals that rely on them for food.