Book contents
- Frontmatter
- Contents
- Preface
- To a mouse
- Chapter 1 The road ahead
- Chapter 2 Patterns in space
- Chapter 3 Patterns in time
- Chapter 4 Dimensionless patterns
- Chapter 5 Speciation
- Chapter 6 Extinction
- Chapter 7 Coevolution of habitat diversity and species diversity
- Chapter 8 Species–area curves: the classical patterns
- Chapter 9 Species–area curves: large issues
- Chapter 10 Paleobiological patterns
- Chapter 11 Other patterns with dynamic roots
- Chapter 12 Energy flow and diversity
- Chapter 13 Diversity dynamics: a hierarchical puzzle
- References
- Index
Chapter 5 - Speciation
Published online by Cambridge University Press: 27 January 2010
- Frontmatter
- Contents
- Preface
- To a mouse
- Chapter 1 The road ahead
- Chapter 2 Patterns in space
- Chapter 3 Patterns in time
- Chapter 4 Dimensionless patterns
- Chapter 5 Speciation
- Chapter 6 Extinction
- Chapter 7 Coevolution of habitat diversity and species diversity
- Chapter 8 Species–area curves: the classical patterns
- Chapter 9 Species–area curves: large issues
- Chapter 10 Paleobiological patterns
- Chapter 11 Other patterns with dynamic roots
- Chapter 12 Energy flow and diversity
- Chapter 13 Diversity dynamics: a hierarchical puzzle
- References
- Index
Summary
Whenever a lineage splits into more than one branch, it has undergone speciation. Yet, I should hate to be asked exactly when the time comes to call them ‘split’. That is like asking exactly when a child becomes an adult. I am content to know that initially there was one lineage and now there are more.
But I would like also to know what mechanism drives the speciation. Like the maturation process of a human being, that mechanism can be studied and described.
Three basic modes of speciation have given us life's diversity:
Geographical speciation
Polyploidy
Competitive speciation
Geographical speciation is the most orthodox. Polyploidy is the best tested. Competitive speciation is the most controversial. You probably learned other words to describe speciation processes, but I believe they all describe one of these three modes.
Geographical speciation
Here is an outline of the process of geographical (also called allopatric) speciation.
A geographical barrier restricts gene flow within a sexually reproducing population.
The isolated subpopulations evolve separately for a time.
They become unlike enough to be called different species.
Often the barrier breaks down and the isolates overlap but do not interbreed (or they interbreed with reduced success).
- Type
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- Information
- Species Diversity in Space and Time , pp. 87 - 111Publisher: Cambridge University PressPrint publication year: 1995