Natural Selection, Antibiotic Resistance, and Evolution

Introduction

• Strep Throat: Caused by bacteria; treated with antibiotics.
• Antibiotics: Destroy prokaryote cells (bacteria) but not eukaryote cells (human cells).

Natural Selection Explained Through Frogs

• Species Variation: Different traits exist even within the same species (e.g., darker and lighter green frogs).
• Predators' Influence: Predators find lighter frogs easier to spot, leading to higher survival of darker frogs.
• Fitness: A biological concept determined by the number of offspring.
• DNA Passing: Darker frogs pass down their DNA; over time, darker frogs' frequency increases in the population.
• Evolution: Change over time due to natural selection.
• Alleles: Recessive alleles may still be present, mutations, and crossing over introduce variety.

Mutations and Variations

• Randomness: Variations and mutations are random; they cannot be "willed" by organisms.
• Fitness Impact: Mutations can be neutral, negative (no offspring), or positive (increased offspring).

Antibiotic Resistance in Bacteria

• Bacterial Variation: Some bacteria have traits (e.g., enhanced cell walls) that resist antibiotics.
• Natural Selection in Bacteria: Antibiotics alter the environment; resistant bacteria have higher fitness and reproduce.
• Gene Transfer: Bacteria can transfer resistant genes to others.
• Impact on Treatment: Resistant strains make some antibiotics less effective.
• Healthcare Challenge: Hospitals face challenges due to bacteria's rapid evolution.

Addressing Antibiotic Resistance

• New Antibiotics: Scientists develop new antibiotics as bacteria evolve resistance.
• Proper Use: Use antibiotics only for bacterial infections, not for viruses.
• Vaccines: Vaccines (e.g., DTaP) protect against severe bacterial infections.

Conclusion

• Stay Curious: Encouragement to remain curious about natural phenomena and developments.