1. Migration Evolutionarily, this means the movement of alleles, or gene flow between populations This will always be less than the movement of individuals

2. Migration When populations differ in allele frequencies, migration can be a powerful force banded unbanded

3. Migration Genetic patterns due to migration tend to be temporary Over the longer term, migration is a homogenizing force—it makes populations more genetically similar D.R. Robertson

4. Migration Populations in Central and Eastern Pacific (divided by 5000 km of deep ocean) are not genetically different in these two reef fish species* D.R. Robertson *(and 18 out of 20 species studied: Lessios and Robertson 2006)

5. Geographic variation in natural populations

6. from Futuyma (1998), p. 259 Often, morphology varies geographically

7. With low migration, allele frequencies vary greatly over small geographic distances

8. from Futuyma (1998), p. 319 As in pocket gophers...  1999 R.M. Timm

9. Geographic barriers to dispersal often separate genetically different populations

10. Historical separations between Gulf of Mexico and SE Atlantic drainages from Avise (1994)

11. from Avise (1994), p. 244 The Florida peninsula is a marine biogeographic barrier It forms a long-term historical barrier to migration and gene exchange (gene flow) within many species

12. Natural selection creates patterns of geographic variation Clinal variation

13. from Volpe and Rosenbaum (2000), p. 110

14. In D. melanogaster, the alcohol dehydrogenase (Adh) locus shows a cline—a regular change in frequency of a trait across a geographic transect from Futuyma (2005)

15. The frequency of Adh F decreases towards the equator on 3 continents: these are parallel clines from Futuyma (2005)

16. Clinal variation at lactate dehydrogenase-B in the mummichog Fundulus heteroclitus: Ldh-B b increases towards the north This allozyme has a higher catalytic efficiency at lower temperatures

17. Races and subspecies

18. A race is a geographic population with well defined, discrete differences in one or more traits Taxonomically, races may be recognized and named as subspecies Red-shafted C. auratus cafer Yellow-shafted C. auratus auratus Subspecies of Northern flicker (Colaptes)

19. Color races of Heliconius butterflies geographic color races of H. erato geographic color races of H. melpomene these races display warning (aposematic) coloration to deter bird predation

21. Allopatric color races Each color race of dart-poison frogs (Dendrobaetes) lives on a different island in Bocas del Toro in western Panamá Most animal color races are allopatric (they occupy non- overlapping ranges)

22. Parapatric races or subspecies share common borders from Futuyma (2005)

23. from Futuyma (1998), p. 258 Parapatric subspecies sometimes interbreed where their borders meet

24. Hamlets: sympatric races? 11-12 forms of Hypoplectrus in Caribbean, Florida, Bahamas Morphologically identical, but strikingly different color patterns 6 “races” live together on the same reefs, and mate like-with-like

25. Racial variation morphological races host races in insects –races feed and oviposit on different host plants –e.g. apple and hawthorn races of Rhagoletis physiological races sex races

26. Physiological races Vermont: embryos survive 5  - 28  New Jersey: 5  - 28  South Florida : 11  - 33  North Florida : 9  - 33  Northern leopard frog Rana pipiens

27. from Futuyma (1998) Sex races