Genes and Population Genetics I

P I1 I2 I3 EP

4 enzymes

Figure 4.1 Plate tectonic processesPlate tectonics: continental drift

5-10 cm/yr

Common ancestorand speciation bydivergence in isolation

Species of large, flightless birds

Early Cretaceousperiod (c. 140 mya)One land mass

Dots = demes

Geographic distribution of a species

Microevolution

1. Macroevolution2. anagenesis andspeciation

MutationsOccur at different levelsPoint mutations

Shift of reading frame

Genetically based phenotypic variation: the material of natural selection

General patterns of natural selection

• Natural selection results in improved fitness; i.e., improved reproductive success.