The Process and the Field of Macroevolution

The return of macroevolution. The field of macroevolution embraces the excitement of seeking an understanding of the breadth of life. We have long desired to know how best to describe the diversity of life's forms and to explain how and why this diversity came to be. No mystery is more intriguing than why we have amoebas and horses, or dandelions and palms. The child's first walk in a meadow, when the child sees flowers and butterflies for the first time, can inspire the same wonder in the most sophisticated biologist walking those same tracks many years later.

We return to this perspective from many quarters of biology and paleontology, after many decades of asking far more restrictive questions that tended to put the process of evolution under a microscope. But now we are stepping back, to take in the broader view. The advances in molecular genetics and developmental biology in recent years have only increased our confidence that the nature of living systems can be understood mechanistically; we can now imagine the possibility of describing the difference between organisms in terms of their genes, gene products, and spatial organization. Such descriptions were beyond our grasp even 10 years ago, but now they are at hand, if still in fragments. The large-scale collation of fossil data and a new understanding of the history of the earth have brought similar increases of confidence among geologists and paleontologists.