#154 Summary Biodiversity and conservation

1 All living organisms may be classified into one of the five kingdoms: prokaryotes, protoctists, fungi, plants and animals.

2 Biodiversity includes the range of habitats (environments) and species in an area, and the genetic diversity within a species.

3 There are moral and ethical reasons for maintaining biodiversity, and also more practical ones. For example, we may be able to use plants to provide medicines, and animals to provide alleles to use in animal breeding.

4 Species may become in danger of extinction through habitat loss, change to their environment (perhaps as a result of pollution) and overexploitation by humans.

5 Conservation of an endangered animal species may involve captive breeding programmes, in which viable populations are built up in zoos and wildlife parks. These programmes try to ensure that the gene pool is maintained and inbreeding is avoided. At the same time, attempts are made to provide a suitable habitat in the wild, so that captive-bred animals can eventually be re-released into the wild. Local people are involved, because this increases acceptance of the project and the chances of its success.

6 Botanic gardens and seed banks help to conserve threatened plant species by breeding them for reintroduction into an appropriate habitat. Seed banks provide suitable conditions to keep different types of seeds alive for as long as possible. Samples of the seeds are grown into adult plants every now and then, so that fresh seed can be collected.

7 Many countries have protected areas called national parks, which often cover large areas. These are set up to conserve rare and endangered species and to maintain their habitats. Often legislation is passed to ensure their protection. In such areas, agriculture is controlled and building, mining and other industries strictly regulated. Access is often limited but not forbidden, as one aim of most such parks is to educate people about the importance of conservation. 8 Other, smaller, conservation areas may be created to protect particular species and habitats.

1. End-of-chapter questions

Which organism is a fungus?

2 Which of the statements about Protoctista are correct?

1 a eukaryote that is not a fungus, plant or animal is a protoctist

2 an organism with cellulose cell walls and chloroplasts may be a protoctist

3 an organism existing as a group of similar cells may be a protoctist

4 a single-celled heterotrophic eukaryote is a protoctist

A 1,2,3 and 4 B 1, 2 and 4 only C 2 and 3 only D 3 and 4 only

3 A gene bank is a store of the genetic variation of a species. Which of the following are gene banks?

1 captive animals in a zoo

2 plants in a botanic garden

3 seeds in a seed bank

4 plant cells growing in tissue culture

5 frozen sperm, eggs or embryos

A 1, 2, 3, 4 and 5 B 1, 2 and 3 only C 2, 3 and 4 only D 3, 4 and 5 only

4 Copy and complete the table to show the features present in the five different classificatory Kingdoms of living organisms. Use a tick (V") to show the presence of a feature and a cross (x) to show its absence.

Add caption

5 Distinguish between orthodox and recalcitrant seeds.

6 a Explain what is meant by biodiversity. [2]

b Over half of the living species of plants and animals live in tropical rainforests. Suggest why this is so. [4]

c Some rainforest species, for example the squirrel monkey in Costa Rica, are endangered. Suggest four ways to conserve an animal species such as the squirrel monkey.[4]

d List four practical reasons why humans should try to maintain biodiversity. [4]

[Total: 14]

7 a In many cases, the reason for an organism becoming endangered is the loss of its habitat as a result of human activity. List four ways in which human activity causes habitat loss. [4]

b In 1973, the population of African elephants in Kenya was about 167000 animals, but by 1989 the population had dropped to about 16000 animals. In 2010 the population had risen to about 36000 animals. Suggest explanations for these changes. [6]

c Explain:

i how captive breeding of animals, such as the scimitar-horned oryx, can help conserve an endangered species; [3]

ii how genetic diversity can be maintained during a captive breeding programme. [3]

[Total: 16]

8 The American crocodile, Crocodylus acutus, was classified as an endangered species by the USA in 1975. It is found in estuarine regions of southern Florida.

The salinity of the water was thought to playa part in the distribution of the American crocodile. The figure shows the number of American crocodile nest sites in areas with water of varying salinity in southern Florida.

a Describe the results shown in the figure. [3]

b Much conservation work has been done in the Everglades National Park in Florida, which is a large wetland area. As a result, the number of nest sites increased from eight in 1975 to 31 in 2000. This led to a rise in the number of crocodiles.

i Calculate the percentage increase in nest sites between 1975 and 2000. Show your working.[2]

ii Suggest two reasons why the population of crocodiles in the Everglades National Park has increased.[2]

[Total: 7]

[Cambridge International AS and A Level Biology 9700/42, Question 1, Mayljune2010,]

2. End-of-chapter answers

1 D
2 A
3 A
4

5 orthodox seeds: can be dehydrated and frozen for long-term storage;

recalcitrant seeds: cannot be dehydrated and frozen;

Exam-style questions

6 a biodiversity:
range/variety, of, species/communities/ecosystems;
the genetic variation within a species;
the genetic variation between species; [max. 2]

b high rate of photosynthesis/rapid growth of plants; allows large number of plant species;
available throughout the year;
provides niches for large number of animal species; [4]

c maintain as a captive population in a zoo/captive breeding;
set up conservation area/protect habitat from clearance;
ban, hunting/capture;
educate public/introduce ecotourism; [4]

d as resource for, food/materials;
as source of alleles for breeding to improve agricultural species;
as potential medicines; for ecotourism/leisure;
to maintain, food webs/nutrient cycles; [max. 4]

[Total: 14]

7 a clearing land for agriculture;
clearing land for housing;
clearing land for industrial building;
clearing land for, road building/railways/pipelines/
other infrastructure;
mining;
logging;
pollution/global warming; [max. 4]

b fall from 167 000 to 16 000 due to a combination of factors including:
ivory hunting;
game hunting;
hunting for meat;

killing after damage to village crops;
habitat loss;
rise after 1989 due to ban on ivory trading;
rise only to 36 000 because other factors still apply: habitat loss;
poaching;
killing after damage to village crops; [max. 6]

c i bred in several places so not all at risk from same disease;
increased numbers of animals;
allows return of animals to wild; [3]

ii close relatives are not interbred; e.g. siblings/father with daughter;
in-vitro fertilisation used to breed from distantanimals;
refer to embryo donation and use of surrogates; [max. 3]

[Total: 16]

8 a more nests in less saline areas;
22 nests at 0–5 parts per thousand compared with 1 at 31–35 parts per thousand;
anomalous result for 16–20 parts per thousand; [3]