Populations & Sustainability (OCR A Level Biology)

Penguins are flightless birds that eat fish. Most species of penguin live near the coast of Antarctica or on the many islands that surround Antarctica.

Fig. 17 shows the populations of three penguin species on an island off the coast of Antarctica.

Fig. 17

Before 1975 the only penguin species on the island was the adélie penguin. Chinstrap penguins were first recorded on the island in 1976.

The changes in the chinstrap penguin population are not directly related to abiotic factors.

Suggest explanations for the changes in the population of chinstrap penguins between 1976 and 2010.

[3]

(ii)

Calculate the mean annual decrease in the adélie penguin population between 1988 and 2010.

Show your working. Give your answer to three significant figures.

[2]

Adélie penguins need a habitat that contains sea-ice. Gentoo and chinstrap penguins can survive without access to sea ice.

Scientists have claimed that the population changes in the three penguin species on the island suggests that the Antarctic temperature is increasing.

(i)

Discuss whether the information in Fig. 17 supports the scientists’ claim.

You should refer to the data in Fig. 17 in your answer.

[3]

(ii)

Scientists working in the local area monitored water temperatures and populations of other water animals around the island between 1976 and 2010.

Suggest two further pieces of evidence that the scientists might have found to support their claim.

[2]

Listed below are three approaches, A, B and C, that can be taken to maintain biodiversity:

A	ex situ conservation
B	in situ conservation
C	preservation

For each of the statements below, indicate whether it could be consistent with in situ conservation, ex situ conservation or preservation by inserting the correct letter or letters in the table.

	Approach
organisms are not removed from their natural habitat
human intervention is happening

The Madidi National Park, in the South American rainforest, is home to a wide variety of species.

The largest predator in the area is the jaguar. These large cats are well camouflaged and hunt mostly at night. A single individual can cover a very large area.

In 2007 the Wildlife Conservation Society (WCS) attempted to estimate the population of jaguars in the Madidi National Park.

• Digital camera traps were placed in areas that jaguars were likely to visit.
• If an infrared beam was broken by an animal, the camera was activated.
• The camera then took a photograph of the animal.

Suggest why it was not appropriate to estimate the number of jaguars using the capture-recapture technique.

 [2]

(ii)

Most studies estimate the population density of jaguars in the South American rainforest to be 5 individuals per 100 km².

In the 2007 study:

• 100 camera traps were set up covering an area of 271 km².

• 28 images of 9 different jaguars were recorded.

How well do these results support a population estimate of 5 individuals per 100 km²?

 [4]

(iii)

Other evidence used to estimate the jaguar population includes footprints and reports of sightings by local humans.

Suggest one disadvantage of each of these methods for estimating the size of the jaguar population.

[2]

The Madidi National Park is also home to approximately 260000 humans who support themselves by means of cattle-farming, and the production of timber and brazil nuts (a large nut harvested from a local native tree).

Conservationists have been working with:

•  local people to promote the sustainable use of these resources
• government agencies to maintain the quality of the national park.

Explain why the Madidi National Park is an example of conservation rather than preservation.

Sustainable food production has become a key focus as the world's human population has increased.

State the meaning of the term sustainable in this context.

One way of increasing the sustainability of food production is to use sustainable fishing methods.

For each of the fishing methods described below, explain how sustainability is achieved:

Hook-and-line fishing involves the use of a fishing rod with several hooks. The rod and hooks are closely monitored by humans during fishing.

[1]

Fishing nets used for catching large fish species have large holes.

[1]

Fishing is only permitted at specific times of year.

[1]

Fig. 2 shows an estimate of the total energy input required to produce 1 kg of each food product.

Fig. 2

Excluding any ideas discussed in part (b), explain how food production could be made more sustainable.

Use the information in the diagram and your own knowledge to support your answer.