The Evolution of Multicellular Development
Publication Year: 2009
The enormous recent success of molecular developmental biology has yielded a vast amount of new information on the details of development. So much so that we risk losing sight of the underlying principles that apply to all development. To cut through this thicket, John Tyler Bonner ponders a moment in evolution when development was at its most basic--the moment when signaling between cells began. Although multicellularity arose numerous times, most of those events happened many millions of years ago. Many of the details of development that we see today, even in simple organisms, accrued over a long evolutionary timeline, and the initial events are obscured. The relatively uncomplicated and easy-to-grow cellular slime molds offer a unique opportunity to analyze development at a primitive stage and perhaps gain insight into how early multicellular development might have started.
Through slime molds, Bonner seeks a picture of the first elements of communication between cells. He asks what we have learned by looking at their developmental biology, including recent advances in our molecular understanding of the process. He then asks what is the most elementary way that polarity and pattern formation can be achieved. To find the answer, he uses models, including mathematical ones, to generate insights into how cell-to-cell cooperation might have originated. Students and scholars in the blossoming field of the evolution of development, as well as evolutionary biologists generally, will be interested in what Bonner has to say about the origins of multicellular development--and thus of the astounding biological complexity we now observe--and how best to study it.
Published by: Princeton University Press
Title Page, Copyright, Dedication
Initially I wanted to sort out in my own mind the relationship between what was developmental biology before the molecular revolution in the middle of the century, and what it is today. I wanted to find a way of looking at the goals and the achievements of both eras to see to what degree they are the same and to what degree they differ. ...
Since the 1940s, I have been thinking about how animals and plants and other organisms develop. As I look back over the many years, I see that the problem remains in some ways much the same, but in other ways it has changed to an extraordinary extent. ...
2 From Embryology to Developmental Biology
Developmental biology started as a descriptive science but progressively became more experimental. Karl Ernst von Baer, in the early 1800s, was one of a long series of descriptive embryologists whose lineage went back to Aristotle; he was the first to see and describe the mammalian egg as well as the fundamental germ layers of embryos. ...
3 The Origin of Multicellularity
The appearance of multicellularity during the course of early evolution is one of the major transitions during the whole span of biological evolution, as Maynard Smith and Szathmary (1995) and others have pointed out. These transitions are especially important in their implications for natural selection because with each transition one moves from one level of selection to another. ...
4 Size and Evolution
The most obvious reason we have multicellular development lies in natural selection. If we could see and understand the external influences that caused development to arise and evolve, we would grasp the origins of development and win some insight into its primordial mechanics. ...
5 The Evolution of Signaling
We often think of the origin of life as fundamentally a problem of the origin of template replication. That certainly is a central property of all living things, and there is no way life could have evolved without it. ...
6 The Basic Elements of Multicellular Development
What we are seeking are the first principles of development. As I have pointed out, there are two ways of achieving this: one is by mathematical modeling, and the other is by looking at the beginning of multicellular development. ...
7 Development in the Cellular Slime Molds
My plan here is to illustrate my main points by examining how they apply to one organism. I want to use the cellular slime molds to show how one can look at their development from the three points of view: the biological, the molecular, and the mathematical. ...
Here are the bare bones of my argument. A basic premise from which all else follows is that most, if not all, the microorganisms that exist today have an ancestry that goes back many millions, if not billions of years. On this foundation I have argued that (1) the size of organisms is under constant selection pressure, and in early earth history, ...
Page Count: 156
Publication Year: 2009
Edition: Core Textbook
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