• Contents



• Preface

Preface

Acknowledgments

ECHINODERM DEVELOPMENT

Laboratory 1 Fertilization and Early Development of Sea Urchins

Laboratory 2 Experimental Investigation of Sea Urchin Development

Laboratory 3 Experimental Investigation of Organization and Differentiation in Echinoderms

Suggestions for Further Investigation of Echinodenn Development

AMPHIBIAN DEVELOPMENT

Laboratory 4 Observations and Experiments on the Living Frog Embryo

Laboratory 5 Patterns of Frog Development

Laboratory 6 Extirpation Experiments, Transplantations, and Parabiosis

Laboratory 7 Dissociation and Reaggregation of Amphibian Embryonic Cells

Laboratory 8 The Primordial Germ Cells of the Frog

Laboratory 9 Experimenting with Xenopus Development

Suggestions for Further Investigation of Amphibian Development

CHICK EMBRYO DEVELOPMENT

Laboratory 10 Patterns of Chick Development

Laboratory 11 In Vitro Culture of Chick Embryos and Embryonic Heart Duplication

Laboratory 12 Surgery on the Chick Embryo

Laboratory 13 Chorioallantoic Membrane Grafting

Suggestions for Further Investigation of Chick Embryo Development

FERN GAMETOPHYTE DEVELOPMENT

Laboratory 14 Patterns of Fern Gametophyte Development

Laboratory 14 Environmental Effects on Fern Gametophyte Development

Laboratory 15 Environmental Effects on Fern Gametophyte Development

Laboratory 16 Sexual Reproduction in the Water Fern, Marsilea

Suggestions for Further Investigation of Fern Gametophyte Development

EMERGING AND REGENERATING DEVELOPMENTAL PATTERNS

Laboratory 17 Pattern Regeneration and Reorganization in Protists and Animals

Laboratory 18 Experimenting with Vascular Plant Development Patterns

Suggestions for Further Investigation of Emerging and Regenerating Developmental Patterns

Appendix A Preparation of Materials for Experimentation on Sea Urchin Embryos

Appendix B Preparation of Materials for Experimentation on Frog Embryos

Appendix C Preparation of Materials for Experimentation on Xenopus laevis

Appendix D Preparation of Materials for Experimentation on Chick Embryos

Appendix E Preparation of Materials for Experimentation on Fern Gametophytes

Appendix F Preparation of Materials for Experimentation on Emerging and Regenerating Developmental Patterns

Appendix G Notes on Course Scheduling and Use of the Manual

As with the earlier editions, the goal of this edition of Patterns and Experiments is to facilitate and encourage developmental biology and embryology laboratory experiences that bring students together with fascinating and dynamic developing systems. Professional biologists and nonbiologists both often relate that the study of some aspect of development of a living organism has been a memorable highlight in their educational experience. How fascinating it is to watch those tiny clusters of cells as one makes that first marathon set of observations of a batch of developing sea urchin embryos. How exciting it is to return to the lab to find a vigorously beating heart in an in vitro cultured chick embryo where there had been no visible heart and a much simpler form only twenty-four hours earlier.

My own view of biology and my career plans changed when I had that experience. I want to say to students who will use this manual that I envy you the excitement that comes with those first opportunities to experiment with living, developing organisms. I hope that a few of you might be inspired to go on to careers researching developmental processes and sharing the fascination of development with your own students. This is a truly exciting time in developmental biology because we are now able to investigate directly many of the genetic mechanisms underlying various developmental processes. However, as you begin your study of developmental biology, whether you pursue that study only in this course or study development for many years to come, I would like to offer one bit of advice from the perspective of many years in developmental biology.As intently as you may study certain individual developmental processes, please try not to lose sight of the whole developing organism and the still broader picture of the role of development in the perpetuation of species. Much of the fascination and beauty of development is to be found at those levels.

This third edition of Patterns and Experiments includes a number of additions and new features. Several of the additions are to the considerably expanded section on echinoderm development. There are much more detailed directions for caring for sea urchin and sand dollar embryos and larvae (Laboratory 1 and Appendix A). Several colleagues have reported that their students have been frustrated with their inability to observe development beyond the earliest stages, and I think that these directions will make it much easier for students to observe additional parts of development.The simpler and more effective procedure for blastomere separation that has been incorporated into Laboratory 2 should make it easier for students to conduct "twinning" experiments like those that have such a rich history in developmental biology's past. Laboratory 2 also includes a fascinating new experiment on the somewhat surprising, but very adaptive, capacity of echinoderm embryos and larvae to regenerate lost cilia. Also, reorganization of the echinoderm portion of the manual led to creation of a new part (Laboratory 3) that includes investigation of differentiation of an enzyme system. This investigation provides students a chance to study specific localized genetic activation in differentiation. Also, "Suggestions for Further Investigation of Echinoderm Development" was reorganized and substantially rewritten.

There is an important addition to the chick embryo section as well. In Laboratory 11, an earlier brief suggestion about investigating heart duplication has been expanded to a full experiment on heart rudiment separation and heart tube duplication that includes informative new illustrations.

Numerous other updates and additions, including several added illustrations, have been made throughout the manual. Well over one hundred new references have been incorporated into the "Suggestions for Further Investigation" that appear at the ends of the portions of the manual. Each set of references has been updated, and the majority of the new references are to works that have been added to the very dynamic literature of developmental biology since publication of the second edition of Patterns and Experiments in 1995.

I've also added citations to a number of the useful websites, many of which have come into being since 1995 as well. I've tried for a modest mix of specialized websites as well as general ones that provide links to many more of the valuable resources now available on the World Wide Web and which are likely to incorporate additional links to important sites that surely will be developed in the coming years.

Developmental biology is not a discipline isolated from other aspects of biology. This is particularly evident, for example, in regard to the worldwide ecological problem of declining populations of numerous amphibian species recognized during the 1980s and 1990s. Appendix G contains some suggestions concerning responsible use of amphibians in teaching that are relevant to this problem. That appendix also contains suggestions of strategies for teaching developmental biology without sacrificing adult vertebrate animals, which is an option that a number of biologists, including me, prefer to choose.

I thank the colleagues and students who have used the earlier editions of this manual and have taken the time to share some of their experiences in developmental biology. They have made insightful comments about the manual and have offered helpful suggestions and criticisms. A number of those suggestions led to additions to the second edition, and others have influenced the development of this third edition. I also warmly thank the many colleagues from colleges and universities across the United States and Canada who have participated over the years in my summer workshops on the Developmental Biology Teaching Laboratory at the University of Maine's Darling Marine Center. Those developmental biologists have brought their own individual perspectives and expertise to the workshop sessions, and we've shared some remarkable learning experiences in that beautiful setting. I owe them and my Darling Center colleagues a great deal.

Finally, I wish once again to offer my thanks to Peter Volpe who was my colleague and mentor in preparation of the first edition of this manual. Several of the amphibian development labs, especially Laboratories 4, 5, 6, and parts of Laboratory 8 have been only slightly updated and have remained largely as Peter conceived them, as has Appendix B. Some years ago, Peter's main interests moved into the areas of human development, medical genetics, and biomedical ethics, and he turned his full energy and attention to those pursuits. Thus, his direct involvement with this manual ended with the first edition, but his influence remains evident in a number of places. The manual's current title stands as a recognition of his original contributions.