3.4.6 Biodiversity within a Community

Question 1

Q: What is biodiversity?

Answer 1

A: Biodiversity refers to the variety of life forms within a given habitat or ecosystem. It encompasses the number of different species (species richness), their genetic diversity, and the variety of ecosystems they form.

Question 2

Q: What is species richness?

Answer 2

A: Species richness is a measure of the number of different species present in a community or habitat. It provides a count of species but does not consider the abundance of each species.

Question 3

Q: What does an index of diversity describe?

Answer 3

A: An index of diversity describes the relationship between the number of species (species richness) and the number of individuals within each species in a community. It provides a more detailed understanding of biodiversity by incorporating species abundance.

Question 4

Q: What is the formula for calculating the index of diversity (d)?

Answer 4

A: The formula for calculating the index of diversity (d) is:

d= ∑n(n−1)
N(N−1)
​
where:

𝑁
N = total number of organisms of all species
𝑛
n = total number of organisms of each species
∑
∑ denotes the sum for all species

Question 5

Q: What does a high value of the index of diversity indicate?

Answer 5

A: A high value of the index of diversity indicates a high level of biodiversity. This means that there are many species and/or that the species are present in relatively even numbers, suggesting a more stable and complex ecosystem.

Question 6

Q: How do farming techniques impact biodiversity?

Answer 6

A: Farming techniques often reduce biodiversity by creating monocultures (large areas of a single crop), using pesticides, and altering natural habitats. This reduces the variety of species and disrupts the balance of ecosystems.

Question 7

Q: What is the balance between conservation and farming?

Answer 7

A: The balance between conservation and farming involves implementing farming practices that minimize harm to biodiversity while maintaining agricultural productivity. Techniques such as organic farming, creating wildlife corridors, and using integrated pest management can help protect biodiversity while allowing for farming.

Question 8

Q: (a) Explain how intensive farming techniques can lead to a reduction in biodiversity. [3 marks]

(b) Suggest two methods that can be used to mitigate the impact of farming on biodiversity and explain how each method helps. [4 marks]

Answer 8

Marking Points:

(a) Reduction in Biodiversity

Intensive farming often involves monocultures which reduce the number of different species. [1 mark]
Use of pesticides and herbicides can kill non-target species, including insects and plants, leading to lower species diversity. [1 mark]
Habitat destruction for creating farmland reduces the area available for wildlife, further decreasing biodiversity. [1 mark]
(b) Methods to Mitigate Impact

Organic Farming: Avoids synthetic chemicals and uses natural pest control methods, which helps preserve beneficial organisms and maintains soil health. [2 marks]
Creating Wildlife Corridors: Establishes areas that connect different habitats, allowing species to migrate and maintain genetic diversity. [2 marks]