1. Modern Evolutionary Theory
Genetics + Natural Selection = Modern Evolutionary Theory

2. Weaknesses in Darwin’s Theory
Did not explain the genetic basis for variations
He said variations occurred, but he couldn’t explain WHY.
Did not consider the origin of life itself

3. Mutations  Variations
Mutations = random changes in the DNA
Mutations in DNA CAUSE variations explained in Darwin’s theory of Natural Selection.

4. Likelihood of Evolution
More Likely to Evolve
Less Likely to Evolve
Sexual Reproduction
Asexual Reproduction
Genetic Variation
No Variation
(Identical to parent)
More Mutations
Less – No Mutations

5. Human Impact on Natural Selection
Resistance to Pesticides
insects naturally resistant to pesticides survive and reproduce
Result: increase in resistant insect population
Resistance to Antibiotics
bacteria naturally resistant to antibiotics survive and reproduce
Result: increase in resistant bacteria population
Overuse of these substances can result in unintentional consequences!