[Maximum number: 1]

The natterjack toad, Bufo calamita, is an endangered amphibian species in the UK. It comes out of hibernation in April and breeds in pools by sand dunes along parts of the UK coast. A young natterjack toad will take about 10 weeks to develop from a fertilised egg. A natterjack toad feeds at night, by running at its prey, mainly insects and worms, on the sand dunes.

Fig. 1.1 shows a natterjack toad.

Fig. 1.1

(a)

Each year the International Union for the Conservation of Nature and Natural Resources (IUCN) publishes a list of endangered species called the Red List. The Red List has a very high proportion of vertebrates compared to invertebrates.

Suggest one reason why the Red List has many more vertebrates than invertebrates.

Question 2 starts on page 6

[ 1 ]

(a)

Discuss the benefits of maintaining the biodiversity of a marine ecosystem, such as that in the coastal waters of Canada.

[ 3 ]

[Maximum number: 1]

The natterjack toad, Bufo calamita, is an endangered amphibian species in the UK. It comes out of hibernation in April and breeds in pools by sand dunes along parts of the UK coast. A young natterjack toad will take about 10 weeks to develop from a fertilised egg. A natterjack toad feeds at night, by running at its prey, mainly insects and worms, on the sand dunes.

Fig. 1.1 shows a natterjack toad.

Fig. 1.1

(a)

Each year the International Union for the Conservation of Nature and Natural Resources (IUCN) publishes a list of endangered species called the Red List. The Red List has a very high proportion of vertebrates compared to invertebrates.

Suggest one reason why the Red List has many more vertebrates than invertebrates.

Question 2 starts on page 6

[ 1 ]

[Maximum number: 2]

Fruit flies of the genus Bactrocera are pests that damage fruit crops.
Table 3.1 gives the names and geographical ranges of Bactrocera fruit flies that were classified as four separate species.

Table 3.1

In 2014, the classification of these flies was changed. All four species were recognised as belonging to a single species, B. dorsalis.

(a)

Suggest how reclassifying B. invadens as B. dorsalis will benefit fruit-producing countries in Africa.

[ 2 ]

[Maximum number: 3]

The Santa Cruz tarplant, Holocarpha macradenia, is a tall annual plant that grows only in the coastal grasslands in California. An annual plant is one that grows, flowers, produces seeds and dies in less than one year.

The tarplant used to be widely spread in California, but there are now only nine natural populations. It is listed as an endangered species.

(a)

(i)

State three reasons why it is important to conserve species.
1.
2.
3.

[ 3 ]

[Maximum number: 2]

Food crops like wheat may be improved by selective breeding and genetic modification.

(a)

Suggest one social advantage and one environmental advantage of growing glyphosate-resistant wheat.
social advantage
environmental advantage

[ 2 ]

[Maximum number: 3]

Biodiversity can be considered at three different levels.

Fig. 5.1, Fig. 5.2 and Fig. 5.3 are images that show these three different levels of biodiversity.

Fig. 5.2

Fig. 5.3

(a)

Prairie strips have environmental and economic effects.

Scientists have made long-term measurements of the environmental effects of prairie strips.
The scientists found that when prairie strips formed 10\% of a crop-field:
- soil erosion decreased by 95 %
- mineral loss from the field decreased by 90 % for phosphorus compounds
- mineral loss from the field decreased by 85 % for nitrogen compounds.

Crop plants need phosphorus (P) and nitrogen (N) to grow.
Evaluate the economic effects of prairie strips on farming.

Question 6 starts on page 18.

[ 3 ]

(a)

In Uganda, many children are infected with HIV from their mothers. This is called vertical HIV transmission.

Uganda has used two ways of trying to reduce vertical HIV transmission. These methods are
- to increase the use of antiretroviral drugs (ARVs) by HIV-infected pregnant women
- to reduce, through contraception, the numbers of unwanted pregnancies.

Table 5.1 shows the percentage reductions in the number of children born with HIV infections and the number of pregnancies in HIV-infected women, that were brought about as a result of the use of ARVs and contraception in 2007.

Table 5.1 also shows the predicted reductions in 2012 if usage of ARVs and contraception increase as expected.

Table 5.1

[ 3 ]

(i)

There is only a limited amount of money to spend on HIV prevention in Uganda.

With reference to Table 5.1, suggest arguments for spending at least as much money on increasing access to contraception as on providing ARVs to HIV-infected pregnant women.

[ 3 ]

(a)

(i)

Suggest reasons for maintaining plant biodiversity.

[ 4 ]

(a)

The Millennium Seed Bank is located in the UK. So far it has successfully stored seeds from 10 % of the world's wild plant species.

[ 3 ]

(i)

Suggest the benefits to humans of conserving plant species.

[ 3 ]