ENVS 1100 Lecture Notes - Lecture 10: Insular Biogeography, Species Richness, Ecosystem Services
3 May 2018
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Biodiversity and the Theory of Island Biogeography
October 7, 2014
Biodiversity is the variety of life on Earth
• Species diversity – variety of species (including its richness and evenness)
• Genetic diversity – heritable variation among individuals of a single
population or within the species as a whole
• Ecological diversity: variety within an ecosystem’s structure
o Population diversity
o Community diversity
Three Components of Biodiversity:
1. Diversity of Genes
• Genetic diversity encompasses the varieties in DNA present among
individuals within species and populations
• Provide the raw material for adaptation to local conditions
• What enables a species to adapt to an ecological change
2. Diversity of Species
• Taxonomy – classification of species
• Species Richness – number of species
o Count the total number of species to measure richness
• Evenness – relative abundance of individuals of different species; are
species rare or abundant
• SIMPSON’S INDEX – takes into account the evenness and richness
3. Ecological Diversity
• Variety of habitats, niches and trophic levels
Biodiversity has Intrinsic and Instrumental value.
Intrinsic Value – worth based on its mere existence; it has an inherent right to exist
Instrumental Value – worth based on its usefulness to humans
Ecosystem Services: benefits that are important to all life
• Includes nutrient cycles, air and water purification, & ecosystem
goods (food/fuel)
1. Cultural Benefits
• Aesthetic
• Spiritual
• Educational
• Recreational
2. Human Provisions
• Food
• Fibre products (cotton/wool)
• Fuel
• Pharmaceuticals
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