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1 - Sexual segregation and the ecology of the two sexes
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- By Kathreen E. Ruckstuhl, Department of Zoology, University of Cambridge, Department of Biological Sciences, University of Calgary, Tim H. Clutton-Brock, Department of Zoology, University of Cambridge
- Edited by Kathreen Ruckstuhl, University of Cambridge, Peter Neuhaus, University of Cambridge
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- Book:
- Sexual Segregation in Vertebrates
- Published online:
- 04 September 2009
- Print publication:
- 05 January 2006, pp 3-8
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Summary
According to Greek mythology, Amazons were female warriors who lived on an island. They occasionally met with men of another people to mate, keeping female offspring and sending male offspring back to their fathers. In many animals too, males and females live apart for most of the year, only gathering for mating. These include many fish species (Sims et al., 2001a), birds (Myers, 1981), lizards and snakes (Parmelee & Guyer, 1995; Shine et al., 2003a), and most mammals with a pronounced sexual dimorphism in body size (Ruckstuhl & Neuhaus, 2000). This book aims at synthesizing our current understanding of the evolution of sexual segregation in different vertebrates, focusing on taxa in which there is sufficient evidence to investigate causes of sexual segregation.
Sexual segregation has caused confusion in the literature, as it can occur at different levels (see Chapter 2 for details). Why, for example, do house mice, Mus musculus, embryos segregate by sex in their mother's womb (Terranova & Laviola, 1995)? Why do African ground squirrels, Xerus inauris, live in separate male and female groups within the same area (Waterman, 1997)? Why do female dogfish, Scyliorhinus canicula, use different feeding and resting areas than males (Chapter 8)? Or why do humans prefer to socialize with same-sex peers (Chapter 12; Maccoby, 1998)? Some species show social segregation of the sexes: males and females are found in different groups outside the mating season, but use the same areas and habitat types (see Chapters 9 and 10).
2 - What is sexual selection?
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- By Tim H. Clutton-Brock, Department of Zoology, University of Cambridge, Cambridge, UK
- Edited by Peter M. Kappeler, Deutsches Primatenzentrum, Göttingen, Germany, Carel P. van Schaik, Duke University, North Carolina
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- Book:
- Sexual Selection in Primates
- Published online:
- 10 August 2009
- Print publication:
- 13 May 2004, pp 24-36
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Summary
In the discussion on Sexual Selection in my Descent of Man, no case interested and perplexed me so much as the brightly-coloured hinder ends and adjoining parts of certain monkeys. As these parts are more brightly coloured in one sex than the other, and as they become more brilliant during the season of love, I concluded that the colours had been gained as a sexual attraction. I was well aware that I thus laid myself open to ridicule; though in fact it is not more surprising that a monkey should display his bright-red hinder end than that a peacock should display his magnificent tail.
C. Darwin, Nature, 2 November 1876, p. 18INTRODUCTION
As this is a book about sexual selection, it is worth starting by considering what it means and how it differs from natural selection. The first section of this chapter briefly reviews the early history of ideas about the evolution of sex differences, while the second examines current definitions of sexual selection and the distinction between natural and sexual selection. The third section synthesises some of the developments in our understanding of the evolution of sex differences since Darwin's day. Finally, the fourth section provides a rough guide to some problems and pitfalls that scientists investigating sexual selection have encountered that are relevant to research on sexual selection in primates.
1 - Introduction to wildlife population growth rates
- Edited by R. M. Sibly, University of Reading, J. Hone, University of Canberra, T. H. Clutton-Brock, University of Cambridge
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- Book:
- Wildlife Population Growth Rates
- Published online:
- 20 May 2010
- Print publication:
- 07 August 2003, pp 1-10
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Summary
This book takes a fresh approach to some of the classic questions in ecology. In particular, what determines where a species lives and what determines its abundance? Despite great progress in the twentieth century much more remains to be done before we can provide full answers to these questions so that reliable predictions can be made as to what will be found in unstudied areas or times. We believe that the methods described and deployed in this book point the way forward. The core message of the book is that key insights come from understanding what determines population growth rate (pgr). We believe that application of this approach will make ecology a more predictive science.
In this chapter we begin with an introduction to the major themes of the book, and then after briefly indicating how population growth rate is defined, we describe the contents of the book in more detail. Those who require more background material will find a brief guide to available texts at the end.
Major themes
In briefest outline, the approach taken in this book is as follows. Questions as to what determines where species live are questions about what values of environmental factors allow populations to persist. Populations persist where pgr ≥ o, so the environmental conditions that produce pgr ≥ o are the conditions in which the species can live. This line of reasoning suggests that to understand what determines where species live, we should study the relationships between environmental factors and pgr.