Evolution, 4th Edition

THE GEoGRAPHy of EvoluTion 483

human-caused climate change; for instance, both the northern (or higher) and

southern (or lower) range limits of several butterflies have shifted to higher lati-

tudes (or elevations) [31]. The northernmost latitude reached by amphibians and

nonavian reptiles introduced into North America by humans matches the spe-

cies’ northernmost limits in their native ranges, suggesting that climate tolerance

determines which species can successfully become established (FIGURE 18.17) [45].

Futuyma Kirkpatrick Evolution, 4e

Sinauer Associates

Troutt Visual Services

Evolution4e_18.16.ai Date 02-02-2017

Time to sympatry (My)

0.2 0.4 0.6 0.8

Divergence

16

32

0

8

24

40

Cranioleuca

sulphurifera

Lepidocolaptes

souleyetii

Lepidocolaptes lacrymiger Limnoctites rectirostris

FIGURE 18.16 Since speciation oc-

curred, pairs of Neotropical ovenbird

species have taken much longer to

become sympatric if their ecological

niches are very similar than if they have

diverged more appreciably in their

niches. This suggests that competition

tends to prevent ecologically similar

species from becoming sympatric. The

difference in their niches (i.e., how they

feed) is inferred from the difference

in morphological features such as the

bill. For example, two morphologically

similar Lepidocolaptes woodcreepers

(left) both feed by probing for insects

that hide on tree trunks; the two birds

at right (a spinetail, Cranioleuca, and a

reedhaunter, Limnoctistes) both inhabit

reedy marshes, but use their differently

shaped bills to glean insects from differ-

ent plant structures. (Graph after [32].)

Futuyma Kirkpatrick Evolution, 4e

Sinauer Associates

Troutt Visual Services

Evolution4e_18.17.ai Date 12-08-2016

Northernmost latitude in introduced range (°N)

105 15 20 25 30 35 40 45 50 55

Northernmost latitude in native range (°N)

30

40

50

55

20

25

35

45

Iguana iguana

Podarcis muralis

FIGURE 18.17 The correlation between the northernmost limit of the range of 35

species of amphibians and reptiles in their native region and in North America, where

they are introduced. Most have not spread farther north than they occur in their native

range. For example, the tropical American green iguana (Iguana iguana, left) has not

spread north of Florida, whereas the European wall lizard (Podarcis muralis, right) is in

New York. (After [45].)

18_EVOL4E_CH18.indd 483 3/22/17 1:39 PM