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26

Explain as to how protection of biodiversity hot spots alone can reduce up to $30 \%$ of the current rate of species extinction.

Explanation

The biodiversity hot spots are regions with very high level of species richness, especially those under threat from humans, thus their protection can reduce the current rate of extinction. These regions can be protected as biological reserves, national parks and sanctuaries.

27

What is the difference between endemic and exotic species?

Explanation

Endemic species are native or indigenous species, which are restricted to a particular geographical region. Exotic or alien species are those species which are introduced from one geographical region to another geographical area. Exotic species may lead to disappearance of native species.

28

How does species diversity differ from ecological diversity?

Explanation

Species diversity refers to the number and distribution of species in an area. It is expressed in terms of 'number of species per unit area' and also as number of individuals of different species in an area.

Ecological diversity refers to the diversity at ecosystem level. It is related to different types of ecosystem habitats e.g., terrestrial (forests, grasslands, etc.) and aquatic (freshwater and marine) ecosystems.

29

Why is genetic variation important in the plant Rauwolfia vomitoria?

Explanation

Plant Rauwolfia vomitoria is a source of drug reserpine which acts as tranqulliser. Genetic variation shown by this medicinal plant might be in terms of the potency and concentration of active chemical (resperin) that plant produces.

30

What is Red Data Book?

Explanation

Red Data Book is a compilation of data or records of species threatened with risk of extinction (which are known to be endangered). The book is maintained by IUCN (headquartered at gland in Switzerland).