The Agents of Evolution
2. Mutation and other heritable changes in the genome
Concept of the genome
Point mutations
Frameshift mutations
Substitutions
Chromosomal Re-arrangements
Duplications
Examples
Polyploidy
Definition
Origin and examples
Importance in speciation
3. Genetic Drift
Sampling error
Bottle neck effect
Founder effect
4. Migration (Immigration, emigration)
5. Non random mating
Sexual selection
Selection based on differences in immune system
Inbreeding
Introduction.
People often get confused about evolution, yet evolution involves processes or as I call them here, agents which are reasonably well understood and not at all mysterious. All evolution from microevolution, to speciation and macro-evolution appears to require different combinations of the same basic set of mechanisms. The purpose of this section is to explore the agents or mechanisms of evolution as they are understood today, and give the reader a foundation for further study about the details of evolution as might be given in more advanced courses. In no way do I mean to imply that we understand everything about how evolution operates, but we do have confidence that the evolutionary history of life on this planet is consistent with basic physical processes that we can at least in principle understand. Here then we deal with the theory of evolution rather than the fact of evolution.
Photo: Walking onions??? Well, why not. This species of onion has specialized flowers that produce new plants by a kind of asexual reproduction. When the young plants are big enough the main stalks bend over allowing the new plants to contact the ground and take root.
Paul Decelles
11/10/01 pgd.