Food Chains

Food Chains

- Living things are all connected

Living things are connected

The variety of living things on Earth is truly amazing. They include humans, whales, ferns, lizards, corals, bacteria, fungi and many more. The scientific word for living things is organisms.\

Living things are connected

But organisms can't survive on their own – they depend on one another. They also depend on the non-living things in their environment such as sunlight, water and soil. A collection of living and non-living things that interact in an environment is called an ecosystem.

Living things are connected

In an ecosystem, each organism has a role to play. For example, a grasshopper might be preyed on by a spider. The grasshopper provides the spider with the nutrients and energy it needs to live.

Multiple Choice

In ecosystems, matter and ______ flow from one living thing to antoher

• food

• energy

• DNA

• water

Multiple Choice

Organisms connected in this way form?

• a dichotomous key

• a family tree

• a food chain

• an energy chain

Multiple Choice

The original source of energy for all living things is?

• The sun

• Water

• Plants

• Oxygen

Multiple Choice

Some organisms use energy from sunlight to make their own food. They are called?

• Producers

• Prey

• Predators

• Comsumers

Multiple Choice

Other organisms cannot make their own food and must eat to get energy. They are called?

• Producers

• Prey

• Predators

• Comsumers

Multiple Choice

Food chains start with?

• Consumer

• Prey

• Predators

• Producers

Multiple Choice

The kelp is a?

• Producer

• Comsumer

Multiple Choice

The sheep are a?

• Producer

• Comsumer

Multiple Choice

The mice are a?

• Producer

• Comsumer

Multiple Choice

The kookaburra is a?

• Producer

• Comsumer

Multiple Choice

The fern is a?

• Producer

• Comsumer

Multiple Choice

The fish are a?

• Producer

• Comsumer

Multiple Choice

The grass is a?

• Producer

• Comsumer

Multiple Choice

The people are a?

• Producer

• Comsumer

Multiple Choice

The trees are a?

• Producer

• Comsumer

Building food chains

Building food chains

Food chains always start with a producer, such as grass, trees, algae or seaweed.

Each arrow in a food chain represents the flow of energy and matter from one organism to the organism that eats it. Energy arrows always point towards the consumer.

In this example, the energy and matter flow from the seaweed to the small fish to the large fish and finally to the orca.

Roles in a food chain

Most food chains have more than one consumer. The consumers are described by how high up the food chain they are. This is shown in the diagram below.

• The consumer that eats the producer is called the primary consumer. All herbivores are primary consumers.

• Whatever eats the primary consumer is called the secondary consumer.

• Whatever eats the secondary consumer is called the tertiary consumer.

• If there is any animal that is large and dangerous enough to eat the tertiary consumer, it is called a quaternary consumer.

If an animal is at the top of a food chain and has no natural predators, it can also be called an apex predator.

Decomposition

Living things produce a huge amount of dead matter. This includes their bodies after they die, but also waste products while they're still alive. For example, trees produce dead leaves and branches, while animals produce faeces, hair and dead skin.

All of this dead matter gets broken down into simpler materials. This process is called decomposition.

Decomposition

Organisms help decompose dead matter in two main ways:

• by eating it, or

• by releasing chemicals.

Organisms that eat dead organisms and waste products are called detritivores. For example, worms eat faeces, dead leaves and other plant and animal scraps.

Decomposition

Organisms that release chemicals to break down dead matter are called decomposers.

For example, mould and bacteria release chemicals that help decompose dead matter. This is what happens when fruits and vegetables rot.

Mushrooms are a type of fungi that decompose dead tree branches. That is why you can often see them growing on a forest floor.

Decomposition

Decomposers and detritivores break down dead matter into simple nutrients. These can be recycled back into the food chain, supporting producers and all of the consumers that depend on them.

For example, worms release nutrients such as nitrogen back into the soil and this helps plants to grow.