3.4.6 Biodiversity within a community

What does biodiversity refer to?

• The number of individuals in a species

• The variety of life in a particular habitat or on Earth as a whole

• The amount of sunlight in a habitat

• The number of habitats in a region

Answer explanation

Biodiversity refers to the variety of life in a particular habitat or on Earth as a whole, encompassing different species, genetic variations, and ecosystems, making it the correct choice.

What is species richness a measure of?

• The number of individuals in a species

• The number of different species in a community

• The total biomass in a habitat

• The genetic variation within a species

Answer explanation

Species richness refers to the number of different species in a community, highlighting biodiversity. It does not measure the number of individuals, total biomass, or genetic variation.

Which of the following best describes an index of diversity?

• The number of habitats in a region

• The relationship between the number of species and the number of individuals in each species

• The total number of organisms in a community

• The amount of rainfall in a habitat

Answer explanation

An index of diversity measures the relationship between the number of species and the number of individuals in each species, reflecting both richness and evenness in a community, making it the best choice.

• The number of different species

• The total number of organisms of all species

• The number of individuals in the most common species

• The number of habitats

• The number of different species

• The number of individuals in each species

• The total number of organisms of all species

• The number of habitats

Which of the following is a consequence of certain farming techniques?

• Increased biodiversity

• Reduced biodiversity

• No effect on biodiversity

• Increased rainfall

Answer explanation

Certain farming techniques, such as monoculture and pesticide use, often lead to habitat destruction and a decline in species variety, resulting in reduced biodiversity. This is why the correct answer is 'Reduced biodiversity'.

Why is it important to balance conservation and farming?

• To maximise crop yield only

• To ensure both food production and the protection of biodiversity

• To reduce the number of species

• To increase the use of pesticides

Answer explanation

Balancing conservation and farming is crucial to ensure both food production and the protection of biodiversity. This approach helps maintain healthy ecosystems while meeting the food needs of the growing population.

Which of the following would NOT increase species richness in a community?

• Introducing new species

• Removing hedgerows

• Planting wildflower meadows

• Creating ponds

Answer explanation

Removing hedgerows decreases habitat complexity and connectivity, which can lead to a decline in species richness. In contrast, introducing new species, planting wildflower meadows, and creating ponds all promote biodiversity.

If a community has a high index of diversity, what does this indicate?

• There are few species present

• There are many species and individuals are evenly distributed among them

• One species dominates the community

• The habitat is very small

Answer explanation

A high index of diversity indicates that there are many species present in the community, and individuals are evenly distributed among them, rather than being dominated by a single species.