Human Impact on Biodiversity (DP IB Environmental Systems & Societies (ESS): SL): Exam Questions

Farmers can plant their crops at different times throughout the year. Traditionally crops were planted in April and harvested in September. However, in modern times farmers have switched to planting their crops in September and harvesting in June/July.

Scientists decided to investigate the effect that the change in planting time had on the number of farmland birds over 10 years. The scientists counted the number of farmland birds found within a 1km radius of farm X that plants its crops in April, and within a 1km radius of farm Y that plants its crops in September.

The figure below shows the data they collected.

Describe the results seen in the figure above.

In recent years, farmers have merged grazing fields together by removing hedgerows, This has resulted in a decline in the diversity of farmland birds.

Explain why.

Organic farms do not use any chemical insecticides.

Suggest what effect organic farming would have on the number of farmland birds.

Explain your answer.

Below is some information about the plant Rafflesia arnoldii:

• It grows in the jungles of South East Asia

• It is noted for having the largest flower of any plant on Earth

• The flower is a bright red-brown colour and grows up to one metre in diameter

• The flower smells like rotting flesh to attract flies, which pollinate it

The photograph below shows a flower of R. arnoldii.

"Anthony and Rafflesia" by timjmansfield is licensed under CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/?ref=openverse.

This species is now classed as endangered.

Suggest three reasons why this plant has become an endangered species.

The Royal Botanic Gardens at Kew plays an important role in plant conservation. Rafflesia arnoldii is one of the plant species that has been conserved at Kew.

Explain why it is sometimes necessary to conserve a plant species, such as R. arnoldii, outside its natural habitat (ex-situ).

The African elephant, Loxodonta africana, is a large herbivorous mammal that mainly feeds on tree leaves. It has the longest gestation period of any land mammal and usually produces one offspring at a time. Its habitat is mainly savannah.

The meerkat, Suricata suricatta, also lives in the savannah of southern Africa. It is a carnivorous mammal and feeds on insects, worms, snails and other invertebrates. It grows up to 30 cm in length and lives in large family groups in burrows.

By contrasting these two species, suggest why the meerkat is less likely than the elephant to become endangered. Use your own knowledge and the information provided above.

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

Suggest two reasons why the Red List has many more vertebrates than invertebrates.

Explain what is meant by the term invasive species. 

Invasive species can impact their new environments in a variety of ways.

Explain the negative effects that invasive species can have on an ecosystem.

The Bali starling, Leucopsar rothschildi, is found on the island of Bali, Indonesia.

The photograph below shows a Bali starling.

The International Union for Conservation of Nature (IUCN) is the world’s largest global environmental organisation. The IUCN Red List of Threatened Species™ evaluates the conservation status of plant and animal species.

The Bali starling is categorised as critically endangered on the IUCN Red List, which means that it is nearly extinct in the wild.

The Bali starling is protected by Indonesian law and trapping of the birds for sale as pets is illegal. In 2001 there were only six Bali starlings in the wild and about 1000 in captivity.

Suggest reasons, other than the trapping of the birds for sale as pets, for the very low numbers of Bali starlings in the wild.

The figure below shows the data for a wolf population and the amount of suitable habitat that is available to the wolves.

Outline the relationship between wolf population size and the amount of suitable habitat between 1970 and 2020.

Calculate the yearly rate of population decline between 1990 and 2000.

An agricultural development company has proposed the conversion of a large area of tropical rainforest into farm land.

Evaluate this potential conversion.

Discuss the conflict between exploitation, sustainable development and conservation in tropical biomes.