11.1 Biodiversity

Question 1

Measuring biodiversity

Answer 1

• Tropical, moist regions have the most biodiversity
• Measuring biodiversity plays an important role in conservation
• It informs scientists of the species that are present, thus providing a baseline for the level of biodiversity in an area
• From this information, the effect of any changes to an environment can be measured
• These may include: human activity, disease or climate change
• Before. major project is undertaken, such as building a new road or the creation of a new nature reserve, an environmental impact assessment (EIA) is undertaken.
• This assessment attempts to predict the positive and negative effects of a project on the biodiversity in that area
• Biodiversity can be studied at different levels:
  1) habitat biodiversity
  2) species biodiversity
  3) genetic biodiversity

Question 2

Habitat biodiversity

Answer 2

• Habitat biodiversity refers to the number of different habitats found within an area.
• Each habitat can support a number of different species.
• Therefore in general, the greater the habitat biodiversity, the greater the species biodiversity will be within that area

Question 3

Species biodiversity

Answer 3

• 2 different components:
  1) species richness - the number of different species living in a particular area
  2) species evenness - a comparison of the numbers of individuals of each species living in a community
• Therefore an area can differ in its species biodiversity even if it has the same number of species
• For example, a cornfield and a grass meadow may both contain 20 species.
• However, in the cornfield, corn will make up 95% of the community with the remaining 5% made up of other organisms including weed plants, insects, mice, and birds.
• In the grass meadow the species will be more balanced in their population

Question 4

Genetic biodiversity

Answer 4

• Genetic biodiversity refers to the variety of genes that make up a species
• Humans have about 25000 genes, but some species of flowering plants have as many as 400000 genes
• Many of these genes are the same of all individuals within a species.
• However, for many genes, different alleles exist. This leads to genetic biodiversity within a species
• Genetic biodiversity within a species can lead to quite different characteristics being exhibited.
• For example, some genes are the same for all breeds of dogs - these genes define the organism as a dog.
• Some of the genes have many alleles - they code for the wide variation in characteristics seen between different breeds of dog
• Greater genetic biodiversity within a species allows for better adaptation to a changing environment, and is more likely to result in individuals who are resistant to disease