Lizards in an Evolutionary Tree

Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles

Jonathan B. Losos
Copyright Date: 2009
Edition: 1
Pages: 528
https://www.jstor.org/stable/10.1525/j.ctt1pnj59
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  • Book Info
    Lizards in an Evolutionary Tree
    Book Description:

    Adaptive radiation, which results when a single ancestral species gives rise to many descendants, each adapted to a different part of the environment, is possibly the single most important source of biological diversity in the living world. One of the best-studied examples involves CaribbeanAnolislizards. With about 400 species,Anolishas played an important role in the development of ecological theory and has become a model system exemplifying the integration of ecological, evolutionary, and behavioral studies to understand evolutionary diversification. This major work, written by one of the best-known investigators ofAnolis,reviews and synthesizes an immense literature. Jonathan B. Losos illustrates how different scientific approaches to the questions of adaptation and diversification can be integrated and examines evolutionary and ecological questions of interest to a broad range of biologists.

    eISBN: 978-0-520-94373-5
    Subjects: Ecology & Evolutionary Biology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-viii)
  3. FOREWORD
    (pp. ix-xii)
    Harry W. Greene

    Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anolesis the tenth volume in the University of California Press’s series on organisms and environments, whose unifying themes are the diversity of plants and animals, the ways they interact with each other and with their surroundings, and the implications of those relationships for science and society. We seek books that promote unusual, even unexpected connections among seemingly disparate topics, distinguished by the talents and perspectives of their authors. Previous volumes have spanned topics as diverse as grassland ecology and bison behavior, but none has encompassed the breadth and depth...

  4. ACKNOWLEDGMENTS
    (pp. xiii-xvi)
  5. PROLOGUE: The Case for Anolis
    (pp. xvii-xx)

    A green lizard sits on the bank at the edge of a tiny stream near the town of Soroa in western Cuba. It may appear unassuming, but this is not your ordinary lizard. Its head is cocked sideways as it peers into the water. Suddenly, it dives into the water, emerging with a small crayfish in its mouth.

    A little later, one of these lizards basks near the water. Another lizard of the same species approaches. They nod their heads at each other, and then the larger one gives chase. As the smaller lizard flees, it comes to the water’s...

  6. 1 EVOLUTIONARY BIOLOGY AS A HISTORICAL SCIENCE
    (pp. 1-10)

    One of the great goals of modern science is to understand biological diversity: where it comes from, how it evolves, and what maintains it. It has fallen to the field of evolutionary biology to try to answer these questions. In attempting to do so, evolutionary biology does not fit the everyday view of science in which hypotheses are put forward and subjected to experimental test.

    The reason is obvious. The scale in space and time is simply too large. It would be wonderful to be able to do an experiment on, for example, the role of interspecific competition as a...

  7. 2 MEET THE ANOLES!
    (pp. 11-28)

    The goal of this chapter is twofold. First, to introduce anoles: what they are, what makes them unique, and where they occur. Second, to focus on what it is to be an anole species. How do species differ from one another? How do we tell one from another? How do they tell one from another? Of course, understanding what constitutes a species is a prerequisite for studying how new species arise from old ones, so this discussion will set the stage for understanding anole evolutionary diversification.

    Anoles are typical lizards in many ways. Consider the following:

    Species range in adult...

  8. 3 FIVE ANOLE FAUNAS, PART ONE: Greater Antillean Ecomorphs
    (pp. 29-58)

    In this and the next chapter, I break anole diversity into five groups, corresponding mostly to the anoles of different regions. “Fauna” is used loosely, as two of these faunas co-occur, and another fauna extends over the majority of the geographic distribution of these lizards. The rationale for this dissection is that these faunas exhibit different patterns of ecological and evolutionary diversity and consequently illuminate different phenomena. Moreover, the amount of study devoted to the faunas varies tremendously; as a result, much of this book will focus on the first of these faunas, the Greater Antillean ecomorphs, which are the...

  9. 4 FIVE ANOLE FAUNAS, PART TWO: The Other Four
    (pp. 59-80)

    Although they’ve received the lion’s share of research, the ecomorphs are not the whole anole story. Not even most of it. In fact, less than one anole species in three is a Greater Antillean ecomorph. In this chapter, I introduce the other elements of anole diversity, namely the unique (or non-ecomorph) anoles of the Greater Antilles, and the anoles of the smaller islands of the Greater Antilles, the Lesser Antilles, and Central America.

    Ninety-five of the 120 anole species on the four large islands of the Greater Antilles belong to one of the ecomorph classes. That leaves 25 which do...

  10. 5 PHYLOGENETICS, EVOLUTIONARY INFERENCE, AND ANOLE RELATIONSHIPS
    (pp. 81-98)

    In the previous two chapters, I have described the distribution and diversity of anoles with little mention of evolution. Yet, some of the patterns of anole diversity beg, no, scream for evolutionary analysis. Are members of the same ecomorph class on different islands closely related? How many times have large and small body size evolved in the Lesser Antilles? Are the West Indian anoles descended from mainland taxa, or did it happen the other way around? In this and the next two chapters, I will discuss how information on anole phylogenetic relationships can be used to address these and other...

  11. 6 PHYLOGENETIC PERSPECTIVE ON THE TIMING AND BIOGEOGRAPHY OF ANOLE EVOLUTION
    (pp. 99-112)

    Our current understanding of anole phylogeny (Chapter 5) provides substantial insight into the evolution of the anole faunas. Throughout the rest of the book, I will frequently use this knowledge to address questions concerning the origin and maintenance of anole biodiversity. In this chapter, I will focus on two seminal, if at times maddeningly inconclusive, issues: When did anoles arise? And how did they attain their current geographic distribution?

    Evolutionary biologists are accustomed to thinking of island radiations as being young in geological terms. This perception no doubt stems from the fact that many of the most famous radiations occur...

  12. 7 EVOLUTION OF ECOMORPHOLOGICAL DIVERSITY
    (pp. 113-134)

    Fortunately, the uncertainties about the biogeographic history ofAnolisdiscussed in the previous chapter have little bearing on understanding of patterns of ecomorphological radiation and diversification, at least within the West Indies. Phylogenetic information indicates that for the most part anoles have radiated independently on each island of the Greater Antilles, regardless of how or when they got there.

    Phylogenetic analysis is critical to investigating patterns of ecomorph evolution. The presence of members of the same ecomorph class on multiple islands could be explained in two ways. On one hand, each ecomorph class might have evolved a single time; in...

  13. 8 CRADLE TO GRAVE: Anole Life History and Population Biology
    (pp. 135-160)

    Before tackling the question of how anole species interact (Chapter 11), and how such interactions might drive evolutionary change (Chapter 12), I need to discuss what makes anoles tick. That is, how do anoles interact with their environment? What happens during the course of an anole lifetime and why? These questions will be the focus of this and the next two chapters.

    The goal of this chapter is to review the basic aspects of anole population biology and life history, as well as to discuss the role of anoles in the ecosystem. In some sense, much of the information that...

  14. 9 SOCIAL BEHAVIOR, SEXUAL SELECTION, AND SEXUAL DIMORPHISM
    (pp. 161-188)

    Sexual selection—“the advantage which certain individuals have over others of the same sex and species solely in respect of reproduction” (Darwin, 1871)—is a topic of great interest to behavioral and evolutionary biologists. The past 25 years have seen a tremendous upsurge in interest in sexual selection, and a concomitant documentation of its near ubiquity throughout the animal and even plant worlds (e.g., Andersson, 1994; Andersson and Simmons, 2006). In addition, we now have a greater appreciation of the many and varied ways in which sexual selection may occur, encompassing not only the traditional views of male combat and...

  15. 10 HABITAT USE
    (pp. 189-204)

    A key factor in understanding anole biological diversity is habitat use. Within localities, coexisting species invariably differ in some aspect of habitat use. Across the landscape, species replace each other as the environment changes. Through time, habitat use evolves within clades in predictable ways. These will be important themes throughout the remainder of the book. In this chapter, I will discuss the various aspects of the environment that are important to anoles, as well as the extent to which habitat use shifts through time.

    I have already discussed how sympatric anole species partition the environment by using different structural microhabitats:...

  16. 11 ECOLOGY AND ADAPTIVE RADIATION
    (pp. 205-232)

    Adaptive radiation is the evolutionary divergence of members of a clade to adapt to the environment in a variety of different ways (Simpson, 1953; Givnish, 1997; Schluter, 2000).258Some of the most spectacular case studies in evolutionary biology are adaptive radiations. Consider Darwin’s finches which, in the absence of many other types of landbirds in the Galápagos, have diversified to adapt to a wide variety of niches usually occupied elsewhere by members of different families (Grant, 1986; Grant and Grant, 2008). Similarly, African Rift Lake cichlids fill an enormous number of ecological roles—from grazers and molluscivores to scale-raspers, eye-pluckers...

  17. 12 NATURAL SELECTION AND MICROEVOLUTION
    (pp. 233-256)

    The anole radiation is characterized by divergence of closely related species into different ecological niches, producing communities composed of ecologically differentiated species. The theory of adaptive radiation presented in the last chapter posits that this diversity is the evolutionary result of ecological interactions between initially similar species.

    Three predictions stem from this theory. Two of these predictions—that sympatric anole species interact and that these interactions lead to shifts in resource use—have been amply documented, as the last chapter attests. The third prediction—that resource shifts lead to evolutionary adaptation—is much more difficult to investigate.

    Until recently, the...

  18. 13 FORM, FUNCTION, AND ADAPTIVE RADIATION
    (pp. 257-290)

    The previous two chapters have focused on the ecological side of adaptive radiation, discussing how interspecific interactions drive ecological shifts and how natural selection subsequently leads to evolutionary change. In this chapter, I take the macroevolutionary perspective: faced with a clade composed of species that are phenotypically differentiated and that occupy distinct ecological niches, how do we test the hypothesis that the phenotypic differences represent adaptations to different ecological circumstances?

    In the case of Greater Antillean anoles, the approach is straightforward. Since the dawn of evolutionary biology, convergence—evolution of the same phenotypic feature by taxa that have independently occupied...

  19. 14 SPECIATION AND GEOGRAPHIC DIFFERENTIATION
    (pp. 291-316)

    Adaptive radiation involves both multiplication of species from a single ancestor and ecological and phenotypic diversification of these species, with the end result that communities are composed of multiple species adapted to different niches. The focus of the last several chapters has been on the second of these two aspects, but the first, the manner in which one ancestral species gives rise to many descendant species, is equally important. Anoles have speciated prolifically, and in the Greater Antilles most of this speciation has occurred within islands, rather than resulting from cross-island colonization and subsequent divergence (Chapter 6). Despite the great...

  20. 15 THE EVOLUTION OF AN ADAPTIVE RADIATION
    (pp. 317-350)

    In Chapter 11, I defined adaptive radiation as the evolutionary divergence of members of a clade to adapt to the environment in a variety of different ways and presented three predictions made by a hypothesis of adaptive radiation:

    Species interact ecologically, primarily by competing for resources.

    As a result of these interactions, species alter their resource use.

    As a result of shifts in resource use, species evolve appropriate adaptations.

    A combination of experimental, observational, and comparative data (reviewed in Chapters 11 and 12) strongly supports these predictions. Thus, Greater Antillean anoles meet the expectations of an adaptive radiation.

    In this...

  21. 16 THE FIVE FAUNAS RECONSIDERED
    (pp. 351-382)

    TheAnolisevolutionary pageant exhibits a fundamental duality. On one hand, the Greater Antillean ecomorphs are renowned for convergence of entire communities, with the same set of ecomorphs evolving repeatedly. On the other hand, only one of the other four anole faunas—the anoles of the small islands of the Greater Antilles—contains many types of ecomorphs. The story of three of the other anole faunas—the mainland, the Lesser Antilles, and the unique anoles of the Greater Antilles—is primarily one of non-convergence, both internally and with the ecomorph radiations.

    The simplest explanation for this contrast is that the...

  22. 17 ARE ANOLES SPECIAL, AND IF SO, WHY?
    (pp. 383-410)

    What’s so great about anoles? Why have I written a whole book about them—and spent more than 20 years studying them—and why have you read the book? Of course, they’re attractive and engaging little creatures, with great variety and entertaining behavior. But if that were their only claim to fame, this book would be of limited interested.

    Quite the contrary, anoles are receiving ever-increasing attention: more and more papers, by more and more research groups, on increasingly diverse topics; even the anole genome is being sequenced. What, if anything, makes them so special?

    I suggest that the interest...

  23. AFTERWORD
    (pp. 411-420)

    In this section, I present a list of all West Indian anole species and of all mainland species mentioned in the text. In addition, Figure A.1 presents the complete phylogeny from Nicholson et al. [2005] that served as the basis for several figures in this book and was used for all original statistical analyses presented here.

    This list is based primarily on Caribherp (http://evo.bio.psu.edu/caribherp/lists/wi-list.htm), last modified December 6, 2007 (at the time of writing). I have not included several island populations that are normally considered as subspecies ofA. marmoratusorA. sagrei(e.g.,A. m. kahouannensisfrom the island...

  24. REFERENCES
    (pp. 421-494)
  25. INDEX
    (pp. 495-507)