Lecture on Natural Selection and Antibiotic Resistance
Introduction
- Discussion on strep throat, a bacterial infection treated with antibiotics.
- Antibiotics target prokaryotic cells (bacteria) and not eukaryotic cells (human cells).
Natural Selection Explained
- Example with Frogs:
- Variation exists within species (e.g., color in frogs).
- Predators can more easily spot lighter frogs, making darker frogs more likely to survive and reproduce.
- Over time, darker frogs become more prevalent due to their increased 'fitness'.
- Evolution occurs as a result of natural selection.
Key Concepts of Natural Selection
- Fitness: Not lifespan, but the number of offspring produced.
- Variation and Mutation: Random; not determined by an organism's needs.
- Can be neutral, negative, or positive in terms of survival advantage.
- Alleles: Might not disappear even if selected against due to recessive traits.
Natural Selection in Bacteria
- Bacteria also exhibit variation.
- Some may resist antibiotics due to traits like enhanced cell walls or enzymes.
- These traits are not 'willed' but are random variations.
- Antibiotic Use:
- Alters the environment, selecting for bacteria that can survive.
- Resistant bacteria reproduce and pass on genes.
- Bacteria can transfer resistance genes to other bacteria.
Implications and Challenges
- Antibiotic resistance is a growing concern, particularly in hospitals.
- Hygiene practices are critical to prevent the spread of resistant bacteria.
- Scientists are continually developing new antibiotics.
- Importance of using antibiotics wisely;
- Only for bacterial infections.
- Misuse can promote resistance.
- Vaccines (e.g., DTaP) are crucial in preventing certain bacterial infections.
Conclusion
- Natural selection can result in observable evolution, such as antibiotic resistance.
- Continuous development of antibiotics and vaccination is vital in managing bacterial infections.
Remember: Stay curious and informed about the ongoing developments in antibiotic resistance and natural selection!