11/10

Biodiversity

• ~1.7 million species

• >50% Cl. Insecta (~1 million species)

  • Mammals - ~6500

  • Beetles - ~300,000

Total Biodiversity

• 5-10 million species??

• Only 5-20% known

• Bacteria, insects, other invertebrates least known

Plant Biodiversity is centered around the equator, along with mammals, reptiles, birds, and invertebrates in both terrestrial, marine, and freshwater ecosystems

• Biodiversity increases towards the equator and decreases towards the poles

Possible causes of high biodiversity

• Evolutionary

  • Faster evolution rates in tropics

  • Longer time to diversify because groups originated in tropics and/or glaciation decreased time near poles

  • Possibly longer time for evolution to occur, or less time towards the poles (glaciation)

• Energetics

  • ^ solar energy and moisture creates ^ food resources

  • ^ solar energy creates less stressful environments

• Habitat Complexity

  • (high) habitat heterogeneity due to 6 land mass/land complexity

  • (high) habitat heterogeneity due to (high) plant structure

• Biotic Interactions

  • (low) competition due to (high) microhabitats/specialization

  • (low) competition due to (high) predation