Lecture Notes on Evolutionary Changes in Rock Pocket Mice

Introduction

• Location: New Mexico's Valley of Fire
  • Dramatic change in landscape due to volcanic eruptions
  • Black rock patches from lava flow about 1,000 years ago
• Evolutionary Theme: Hide and seek between predators and prey

The Rock Pocket Mouse

• Habitat Adaptation
  • Light-colored fur blends with desert sands
  • Dark lava background makes light-colored mice vulnerable
• Predators
  • Visual predators include foxes, coyotes, rattlesnakes, owls, and hawks

Evolutionary Changes

• Natural Selection
  • Predators weed out mice that don't match the background
  • Evolutionary pressure leads to dark-colored mice on lava
• Mutation
  • Mutations introduce dark fur in mice
  • Random and rare but can lead to advantageous traits

Research by Michael Nachman

• Genetic Research
  • DNA sampling of light and dark mice
  • Focus on genetic mutation causing dark coloration
• Mc1r Gene
  • Difference in four chemical letters between dark and light mice
  • Controls dark pigment in mouse hair follicles
  • Advantageous on dark backgrounds

Spread of Dark Fur Mutation

• Rapid Evolution
  • Mutation spread rapidly over 1,000 years
  • Math: Advantageous traits increase in population due to higher reproductive success
  • 1% advantage spread in 1,000 years; 10% advantage in 100 years

Evolutionary Insights

• Simple Ecological System
  • Dark vs. light rocks, dark vs. light mice
  • Clear illustration of Darwin's natural selection
• Random Mutation vs. Non-random Natural Selection
  • Mutation is random; natural selection is not
  • Selection sorts winners and losers

Evolutionary Repetition and Adaptation

• Consistency of Evolution
  • Different genetic mutations lead to similar adaptations
  • Independent lava flows led to similar evolutionary results
• Repeated Evolutionary Outcomes
  • Same environmental conditions lead to similar evolutionary paths
  • Demonstrates ongoing evolutionary process as environments change

Conclusion

• Evolution is continuous and adaptive
• The rock pocket mouse case illustrates how species adapt and re-adapt in response to environmental changes
• Insights into the non-random nature of natural selection in evolution

[MUSIC PLAYING]