Food chains and predator-prey graphs
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Explainer Video
Summary
Food chains and predator-prey graphs
In a nutshell
Food chains show which organisms eat what. They start with producers and then contain consumers. Predator and prey populations are linked: changes in one population directly affect the other population.
Food chains
Food chains are a way of showing what is eaten by what. They always start with a producer.
Example
Here is an example of a food chain.
Producers
Producers make their own food using energy from the Sun. Some glucose is used to make the plant's biomass. This is the mass of living material. Biomass is passed along a food chain when an organism eats another organism.
Example
Green plants and algae make glucose by photosynthesis.
Consumers
Consumers are organisms that eat other organisms.
| 1. | Producer. |
| 2. | Primary consumers eat producers. |
| 3. | Secondary consumers eat primary consumers. |
| 4. | Tertiary consumers eat secondary consumers. |
Predator and prey populations
Predator and prey populations go in cycles. Consumers that hunt and kill other animals are called predators. The animals that predators eat are called prey. In a stable community, the population size of a species is limited by the amount of food it has. This means the population size of predators is directly affected by the population size of prey.
| i. | Foxes are predators, rabbits are prey. |
| ii. | If the number of rabbits increases, the number of foxes will also increase as they have more food. |
| iii. | As the number of foxes increases, the number of rabbits will decrease as more rabbits are eaten by the foxes. |
Note: It takes a while for one population to respond to changes in the other as it takes time for foxes to reproduce.
FAQs - Frequently Asked Questions
What are prey?
The animals that predators eat are called prey.
What is a predator?
Consumers that hunt and kill other animals are called predators.
What is a consumer?
Consumers are organisms that eat other organisms.
What is a producer?
Producers make their own food using energy from the Sun.