The sub-Antarctic Pipit is a threatened bird species native to isolated Southern Ocean islands. The diagram shows the food web on one of these islands:
How many secondary consumers are in this food web?
House mice are described as both predators and competitors of Pipits. Explain why.
Biomass is lost as it passes through this food web. Identify two processes from the list below that result in biomass loss from this food web:
- egestion
- growth
- active transport
- respiration
Domestic cats were originally introduced to some sub-Antarctic islands by humans to control pest house mouse populations. Which term describes this type of pest control? Choose from:
- Abiotic control
- Biological control
- Chemical control
- Cultural control
Female house mice can breed 6 times each year and produce 6 pups each time. The Pipit lays about 3 eggs each year. Explain why the house mice can rapidly drive the Pipit towards extinction.
By the late 20th century, the Pipits survived only on a small mouse-free offshore islet. Conservationists proposed building a research station and a helicopter landing pad on this offshore islet.
Suggest why these birds survived on the offshore islet.
Suggest two reasons why conservationists are against the proposal to build the research station and landing pad.