Geographic variation, speciation, and clines / John A. Endler.

Format:

Book

Author/Creator:

Endler, John A., 1947-

Series:

Monographs in population biology ; 10.

Monographs in population biology ; 10

Language:

English

Subjects (All):

Clines.

Evolution (Biology).

Physical Description:

ix, 246 pages : illustrations ; 23 cm.

Place of Publication:

Princeton, N.J. : Princeton University Press, 1977.

Summary:

This book explores the origins and development of geographic variation, divergence, and speciation. In particular it is concerned with genetic divergence as it is usually found on continents, among groups of populations isolated only by distance. Although earlier writers on this topic considered the effects of geography and dispersal, intense geographic differentiation and speciation were thought to require complete isolation. Professor Endler shows how geographic differentiation and speciation may develop in spite of continuous gene flow.

Following a review of the diverse and scattered literature on gene flow and population differentiation, the author discusses the relationships among gene flow, dispersal, and migration. He then summarizes the factors which limit the geographic extent of gene flow, and those which allow steep clines to develop in the absence of barriers to gene flow. His analysis draws on examples from the field, experiments, and single- and multiple-locus models.

The mechanism and conditions for parapatric speciation are presented: steepening clines, development into hybrid zones, and the evolution of sexual isolation. In the final chapter the author considers the interpretation of natural clines and the associated geographic patterns of subspecies and species.

Contents:

2. On gene flow 20

3. Properties of clines 30

3.1. Measurement of differentiation 30

3.2. Genetic sampling drift 33

3.3. Environmental gradients 53

3.4. Spatially abrupt environmental changes 80

3.5. The gradient and stepped environment models 88

3.6. Secondary contact 89

4. Experimental clines and the effects of interaction among different loci 97

4.2. Models of coadaptation 98

4.3. A Drosophila experiment 108

4.4. The effect of linkage 136

5. Parapatric speciation 142

6. Secondary or primary intergradation? 152.

Notes:

Bibliography: pages 187-239.

Includes indexes.

ISBN:

0691081875 :

0691081921

OCLC:

2645720