What is information transfer?
In an ecosystem, energy flows and materials move in cycles. A third thing also moves: information. Information is a message that one living thing sends and another living thing receives.
The message can go between two animals of the same kind, between different species, or between a plant and an animal. It can also come from the non-living world, such as the length of the day, which tells plants when to flower.
Information is different from energy. Energy only moves one way, from the Sun to producers to consumers. Information can go both ways: the sender can also become a receiver.
Physical information
Physical information uses things you can see, hear or feel: sound, light, colour, shape, heat and touch.
- A bird sings to say, "This is my area."
- Bright flower colours show insects that nectar is here.
- Fireflies flash light to find a mate.
- Bats send out sound and listen to the echo to find insects.
Sound travels fast. In air it moves about 340 metres every second.
Chemical information
Chemical information uses substances that carry a message. The most famous are pheromones: chemicals made by an animal that change the behaviour of another animal of the same species.
- A female moth releases a smell. A male moth can sense it from far away.
- Ants leave a chemical trail so others can follow to food.
- Flowers give a sweet scent to attract bees.
- Some plants release a smell when insects bite them, so that other plants nearby get ready to defend themselves.
Chemical messages last a long time and work even in the dark, but they are slow and the wind can carry them away.
Behavioural information
Behavioural information uses actions and body language.
- A honeybee does a waggle dance in the hive. The direction of the dance shows where the flowers are, and its length shows how far.
- A dog bares its teeth to warn, or wags its tail to greet.
- A male peacock spreads and shakes his tail to attract a female.
- A deer raises its white tail when it runs, and others in the herd follow.
Why information transfer matters
Messages help life in an ecosystem in many ways:
- Finding food: the bee dance, ant trails.
- Reproduction: songs, colours and scents bring mates together at the right time.
- Safety: alarm calls warn the herd or flock.
- Balance: signals help regulate populations. For example, territory calls spread birds out so they do not all crowd in one place.
- Between species: flowers and pollinators depend on colour and smell. Both gain.
People use this knowledge too. Farmers hang pheromone traps to catch pests without spraying much poison, and light traps pull insects away from crops.
Try it: three-message game
Play this with two friends. One is the sender and one is the receiver. Send a message "come here" in three ways: (1) clap or whistle, (2) hold up a bright cloth, (3) use only a dance with no sound. Then ask a third friend to hide a strong-smelling piece of orange peel and let the receiver find it by smell. Which message was fastest? Which worked in a noisy room? Check your guess in the 3D by pressing each button.
Key formulas and definitions
- Physical = sound, light, colour, shape
- Chemical = pheromones, scents
- Behavioural = dances, displays, postures
- Time = distance ÷ speed (sound: about 340 m/s)
Worked examples
1. A bird gives an alarm call. A hawk is 680 m away. Sound travels at 340 m/s. How long does the call take to reach the hawk? What kind of information is it?
Time = 680 ÷ 340 = 2 seconds. It is physical information (sound).
2. A male silk moth flies 2 km to a female without seeing her. Which kind of information did he use, and how do you know?
Chemical information. He was too far to see or hear her, so he sensed her pheromone carried by the air.
3. A honeybee dances in the hive and other bees fly straight to a far-away field of mustard flowers. Name the kind of information and say what each part of the dance tells.
Behavioural information. The direction of the dance shows the direction of the flowers. The length of the dance shows how far they are.
Common mistakes
- Thinking information flows like energy. Energy moves one way and is lost as heat. Information can move both ways and is not used up.
- Calling a pheromone a physical message. It is a chemical, so it is chemical information.
- Thinking only animals send messages. Plants also send messages: scent, flower colour and chemicals released when they are eaten.
- Mixing up behaviour and sound. A dance with no sound is behavioural. The calling sound of a bird is physical.