How Nature Works
Ecosystems and food chains
Separate the living and non-living parts of a habitat, build a food chain, and name the three ways two organisms can live together.
Look into a pond and list what you find. Fish, frogs, snails, duckweed, algae — and water, soil, sunlight, a temperature. Two lists, and neither can be crossed out: the fish takes its food from the small plants and animals, and its oxygen from the water. Take away either list and the pond stops being a pond.
Biotic, abiotic, ecosystem
The living things in a habitat are its biotic components; the non-living things — air, water, soil, sunlight, temperature — are its abiotic components. The two interacting together make an ecosystem. Ecosystems come in two sorts: aquatic, such as ponds, rivers and lakes, and terrestrial, such as forests, farms and grasslands.
Worked example
Researchers compared two ponds. Pond A had fish and plenty of flowering plants around it; pond B had no fish and fewer flowering plants. How could fish in the water affect flowers on the bank?
Start one link back: fish eat dragonfly larvae, so pond A had fewer dragonflies than pond B.
The first link is the direct one, and it is the one you would have predicted. The interest is in what follows it.
Try it together
A grassland holds grass, grasshoppers, frogs, snakes and eagles. Build the feeding relationships into a chain.
One word for each answer.
1.Which of the five makes its own food, and so stands at the start of the chain?
Have a go
Have a go on your own. A place that provides the right conditions for an organism to live and grow has a one-word name. What is it?
Ready to practise?
Eight questions on what you have just read. Nothing is timed, and you can play as many times as you like.