The Biological Resources & The Biodiversity Crisis

Earth’s Formation and Evolution

• Formation of Earth: Formed approximately 4.6 billion years ago
• Timeline of Life:
  • First life forms arose ~3.8 billion years ago
  • Multicellular life evolved ~2.1 billion years ago
  • Eukaryotes appeared shortly after
  • Our species, Homo sapiens, evolved approximately 200,000 years ago

Biodiversity Overview

• Current Estimates:
  • Between 5 million and 100 million species exist on Earth
  • Only about 1.5 million species are formally described

The Biodiversity Crisis

• Sixth Mass Extinction:
  • Current biodiversity crisis deemed as the sixth mass extinction event
  • Extremely rapid species loss documented in recent decades
  • Estimates suggest 13% to 41% of described species are threatened with extinction
  • Extinction rates now exceed 1000 times the natural background rate
  • Average populations of animals have declined by 60% in the last 40 years
  • Factors:
  • 99% of current extinctions driven by human activity

Human Population Impact

• Population Growth:
  • Historical context shows rapid increase from 1 billion in 1805 to 7.6 billion by 2018 and predicted ~9.6 billion by 2050
• Resource Consumption:
  • Increasing population leads to higher resource consumption, directly impacting biodiversity

Major Threats to Biodiversity

• Human Activities:
  • Urbanization, agriculture, logging, and fishing practices contribute significantly
  • Habitat loss through fragmentation and degradation
  • Overexploitation of species and ecosystems
  • Introduction of invasive species and diseases
  • Climate change altering ecosystems and species survival

Types of Extinction

• Extinction Types:
  • Extinct: No remaining individuals (e.g., West African Black Rhino)
  • Extinct in the Wild: Only existing in captivity (e.g., Scimitar-horned oryx)
  • Ecologically Extinct: Populations too small to affect ecosystems (e.g., Pygmy tarsier)
  • Extirpation: Local extinction in specific areas (e.g., Gray wolf)

Patterns of Extinction

• Higher extinction rates on islands due to limited ranges and small populations
• Freshwater species experience greater declines compared to marine species
• Historical Context:
  • Passenger pigeon: once billions, extinct by 1914 due to overhunting and habitat loss

Vulnerability to Extinction

• Traits Associated with Vulnerability:
  • Rare and endemic species, specialized habitat needs, small population sizes, and more
  • Climate change exacerbates these vulnerabilities
• Current Human Impact:
  • Habitat destruction, pollution, and human encroachment further affect species

Conservation Priorities

• Understanding traits and current conditions is crucial for prioritizing species for conservation efforts
• Group Activity Suggestion: Rank species based on traits indicating extinction risk
  • Examples include Bornean Orangutan, Ploughshare Tortoise, and others

Conclusion

• Biodiversity loss has dire implications for human well-being and ecosystem services
• Urgent action is needed to mitigate the impacts of human activities on biodiversity to conserve our planet's ecological integrity.