Introduction to Biodiversity (IBESS Topic 3.1)

Overview

• Biodiversity is crucial for the health of Earth.
• IB significant ideas:
  • Biodiversity has various forms: species, habitat, and genetic diversity.
  • Understanding and quantifying biodiversity is vital for conservation efforts.

Definitions

• Biodiversity: Variability among living organisms from all sources, includes diversity within species, between species, and of ecosystems.
  • Species Diversity: Measure of species richness and relative abundance.
  • Genetic Diversity: Total genetic characteristics within a population's gene pool.
  • Habitat Diversity: Range of different habitats in an ecosystem or biome.

Importance of Biodiversity

• Nature's Insurance: Diverse systems are resistant and resilient to change.
• Source of Natural Capital: Recycling and purification of chemicals.
• Result of Evolution: Millions of years of evolution make it irreplaceable.

Types of Diversity

Genetic Diversity

• Larger populations = higher genetic diversity.
• Example: Cheetahs have low genetic diversity affecting survivorship.

Species Diversity

• Estimated 8.7 million species on Earth.
• High species diversity examples in aquatic systems.

Habitat Diversity

• Example: El Refugio, Bolivia, with varied habitats.
• Greater habitat diversity leads to greater species and genetic diversity.

Successional Time and Diversity

• Diversity increases as habitats become more complex.
• Climax communities lead to species equilibrium.

Factors Affecting Diversity

• Larger areas often have higher species diversity.
• Altitude and climate changes can increase diversity.
• Human activities can also influence diversity positively (e.g., polyculture).

Measuring Diversity

• Species Diversity: Combination of richness (number of species) and evenness (individuals within species).
• Simpson Diversity Index (D): Accounts for species richness and relative proportions.
  • Example calculations: Sample 1 vs Sample 2.
  • High D values suggest stable sites; low D values can indicate human impact.

Conservation Efforts

• Importance of identifying high biodiversity areas.
• Challenges in determining conservation areas (e.g., deserts vs. rainforests).
• Role of natural selection in diversity development.

Biodiversity Hotspots

• Areas with high biodiversity under threat.
• Characteristics: Rich in endemic species, mostly tropical.
• 17 mega diversity countries hold two-thirds of all species.

Summary

• Biodiversity manifests in genetic, species, and habitat diversity.
• Habitat diversity influences species and genetic diversity.
• Quantification of biodiversity aids conservation and tracks human impact.

Additional Resources

• William Green's presentation and Dave Hoover's YouTube channel.
• IBESS textbook for further study.