1. The process of (micro)evolution
Natural Selection today

2. Objectives
Outline how variation, adaptation and selection are major components of evolution.
Discuss why the evolution of pesticide resistance in insects and drug resistance in microorganisms has implications for humans

3. Steps in evolution
Variation occurs within a population due to mutation.
There is selection pressure.
Some variants are more suited to survive in the environment than others.
The best adapted survive and breed.
Advantageous features are passed on to the next generations
Over time the population will become well adapted to an environment

4. New species
New species only arise if subgroups become so adapted to different environments that they are no longer able to interbreed and produce fertile offspring.

5. Natural Selection can be a problem
Pesticides are chemicals used to kill insects or other animals that damage crops or spread disease.
When mosquitoes are first sprayed with insecticide most of them are susceptible. If they absorb a big enough dose they will die.
A few mosquitoes have mutations which allow them to break down the insecticide, or prevent the insecticide from being absorbed into their cells

7. Resistance not immunity
The insects become resistant to insecticide.
This is not the same as immunity.
Organisms are only immune if they develop antibodies against an invading antigen.

8. The nature of the problem
Human need to keep on developing new pesticides to stay ahead of the evolution of resistance.

9. Examples
Resistant mosquitoes spread the Plasmodium pathogen. (Causes malaria).
Head lice no longer susceptible to treatment
Some pathogenic bacteria have become resistant to antibiotics.

10. The solutions?