Evolution, 4th Edition

Futuyma Kirkpatrick Evolution, 4e

Sinauer Associates

Troutt Visual Services

Evolution4e_19.15.ai Date 02-02-2017

Spurred

Non-spurred

Aquilegia

Isopyrum

Semiaquilegia

Nectar spurs

No spurs

Aquilegia

Isopyrum

FIGURE 19.15 Enhanced diversification at-

tributable to a key adaptation. The evolution

of nectar spurs in the ancestor of colum-

bines (Aquilegia), shown by the red cross-

bar, was followed by the origin of numerous

species within a short time, as shown by the

shortness of the branches between specia-

tion events. The sister group (Isopyrum) that

lacks spurs did not diversify as abundantly

or as quickly. Columbines that differ in spur

length have different pollinators, which

serve as different resources, but also reduce

gene exchange among diverging colum-

bine populations and contribute to repro-

ductive isolation. (After [59]; data from [30].)

Futuyma Kirkpatrick Evolution, 4e

Sinauer Associates

Troutt Visual Services

Evolution4e_19.16.ai Date 12-12-2016

0.2 0.4 0.6 0.8 1.0

Predators

Hap egg dummies

Egg dummies

Sexual dichromatism

Polygamy

Elevation

Residual latitude

Energy

Depth

Surface area

0.0

Relative importance

(A) (B) Radiations of at least ve species

Radiation: more than 5 species

Radiation: more than 2 species

No radiation

Ecological

factors

Cichlid

factors

FIGURE 19.16 Diversification of African cichlid fishes is attributable both

to ecological opportunity and to speciation associated with sexually select-

ed traits. (A) The colored circles mark the many lakes in which cichlids have

been sampled. Bright red circles show lakes in which there was at least

one speciation event; yellow circles are lakes in which at least one lineage

has five or more species. (B) Factors that have been important in fostering

speciation within lakes. The most significant factors that are correlated with

speciation are lake depth, amount of incident solar energy, sexual color

difference, and egg dummies in haplochromine cichlids. Egg dummies

are colored spots on the males’ fins that attract females. (From [75].)

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