Review of Modern Synthesis, its gaps and how the extended evolutionary synthesis can help fill these gaps
Pigliucci 2009
Modern synthesis in a nutshell
Futuyama 2006:
- Genetic variation arises by random mutation and recombination
- Populations evolve via gene flow, drift and especially natural selection
- Most adaptive genetic variants cause very slight phenotypic effects, so change is gradual
- Speciation by gradual evolution of reproductive isolation
Niche construction, altered environments can be inherited, for example Beaver Dam construction
Odling-Smee et al 2003
Many routes of inheritance: Standard, epigenetics (methylation), behavioural, symbolic
Jablonka & Lamb 2005
Epigenetics: Mechanisms of inheritance that do not include the DNA sequence
Nancy 1958
Selecting on phenotype, not genotype, and implications
- Phenotypic accommodation
- Genetic assimilation
- Genes follow selection pressures, rather than creating them
If you have an environmental component to phenotype, and phenotype is under selection, then how is it that the genes continue to evolve?
Though it is hard to pick out 1:1 interaction between gene and phenotype, this does not make them any less important than environmental factors… we just don’t know the different levels of interaction of environment and gene on the phenotype overall.
At what point do we call something evolution – does lack of change in gene frequencies over time matter, if it is the phenotype that is changing?
Problems with modern synthesis
- Other mechanisms of inheritance?
- How to plasticly complex traits arise?
- Other generators of variation?
- Difference between micro and macro evolution?
- Role of development on adult phenotype and implications?
