Lecture Notes: Wolves, Extinction, and Ecosystem Management

Wolves: Myths vs Reality

• Mythology and Reality
  • Wolves often depicted negatively in myths, legends, and fairy tales.
  • No documented wolf attacks on humans; myths persist regardless.
• Characteristics of Wolves
  • Carnivorous, pack hunters, nocturnal.
  • Distinctive nighttime howls contribute to their mythical image.
• Impact on Farming
  • Prey on farm animals like cattle and sheep.
  • Historically disliked by ranchers.

Wolves in the United States

• Extinction in Early 20th Century
  • Last native wolf shot in Yellowstone, leading to ecological imbalance.
• Reintroduction Efforts
  • Early 1990s: Wolves reintroduced from Canada to Yellowstone.
  • Fenced area established initially, later removed.
  • Successful multiplication of wolf packs; ecological balance restored.
• Controversy and Legal Issues
  • Divided opinions on wolves' ecological role.
  • Endangered Species Act compensates ranchers for livestock losses.
  • Legal challenges and restrictions on shooting wolves.

Other Species: Grizzly Bears

• Grizzly Bears in the U.S.
  • Symbolic on California state flag despite historical extinction.
  • Present in some state parks, common in Alaska.
• Economic Impact
  • Rise of ecotourism makes grizzly bears economically valuable alive.

Extinction and Mass Extinctions

• Historical Mass Extinctions
  • 65 million years ago: Massive asteroid impact in Yucatan, Mexico.
  • Caused darkness, freezing temperatures, and mass extinction (50% of species).
  • Key evidence: Crater, iridium layer, spherical rock droplets.
  • Other mass extinctions occurred, with varying theories on causes (e.g., volcanic activity).
• Current Human-Caused Mass Extinction
  • Estimated 50% of species extinct in the last century due to human activity.
  • Potentially a "sixth mass extinction" comparable to previous natural events.
  • Human impacts on the biosphere are ongoing and accelerating.

Conclusion

• Conservation Challenges
  • Balancing ecological restoration with economic and social concerns.
  • Importance of understanding historical and current extinction events.
  • The need for ongoing conservation efforts to mitigate human impact on biodiversity.