Ecosystems and biodiversity - AQA SynergyPredator-prey cycles
An ecosystem is the living organisms in a particular area together with the non-living components of the environment, such as soil, air and water. An ecosystem is biodiverse if it contains many different species.
In a healthy, balanced ecosystemThe living organisms in a particular area, together with the non-living components of the environment. the numbers of predatorAn animal that hunts, kills and eats other animals for food. and preyOrganisms that predators kill for food. remain fairly constant. They can go up and down during each year, but generally over the years, these increases and decreases remain fairly constant.
If numbers of either predators or prey increase or decrease, it could be due to a change in the abioticNon-living elements of an ecosystem, such as climate, temperature, water, and soil type. factors, like water or sunlight, or bioticLiving elements of an ecosystem, such as plants and animals. factors, like a new predator or pathogenMicroorganism that causes disease.. This would result in a less balanced ecosystem.
An example is shown in the graph below and shows characteristic repeating patterns called predator-prey cycles.
Figure caption,
Predator-prey cycles by population size and time
The graph shows that there is almost always more prey than predators. It also shows the following patterns:
The number of predators increases because there is more prey.
The number of prey then reduces because there are more predators.
The number of predators then reduces because there is now less prey.