Allopatric speciation Harris groundsquirrel Whitetailed ground squirrel Allopatric

Allopatric speciation Harris’ groundsquirrel White-tailed ground squirrel

Allopatric speciation Albert’s squirrel Kaibob squirrel

Hawaiian Drosophila

Speciation due to dispersal. . . Fig. 22. 16

. . . can give rise to huge numbers of species. Adaptive radiation. Fig. 24. 11

Speciation in the lab Fig. 24. 12

Fig 23. 1

high Wind direction Tolerance to metals low Adults Off mine tailings Adults On mine tailings

Sympatric speciation? Many species in small isolated, bowl-shaped lake. Schliewen, et al. 2001. Genetic and ecological divergence of a monophyletic cichlid species pair under fully sympatric conditions in Lake Ejagham, Cameroon. Molecular Ecology 10: 1471.

Sympatric speciation ? ?

Sympatric Speciation • Closely related species often sympatric • Disruptive selection • Assortative mating

Fig 24. 13 Polyploidy Self fertilization New species with 2 n = 12 2 n = 6 Error during meiosis makes gametes with n = 6

Gametes Zygote - infertile

2 n = 14 2 n = 28

IV. Macroevolutionary Pattern A. Tempo of Speciation 1. gradualism 2. punctuated equilibrium B. Phylogenetic Reconstruction 1. an example 2. the problem of convergent evolution 3. molecular traits

Fig. 24. 17

salamander frog mouse bird lizard E D B C A snake

Current species: salamander frog mouse bird lizard E D B C A snake

ancestors: salamander frog mouse bird lizard E D B C A snake

Fig 22. 14 humerus ulna radius carpals phalanges

Some snake species still have non-functional pelvis bones and little leg bones.

Source: Ray Troll, in Matsen and Troll 1994 Planet Ocean. Ten Speed Press, Berkeley.

The problem of convergent evolution: the Tasmanian wolf is more closely related to the kangaroo than it is to the North American red wolf Red Wolf Tasmanian Wolf

Homeobox (Hox) genes have same order, structure and similar pattern of expression in mouse and fly!