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Chance and necessity: the evolution of morphological complexity and diversity
1Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin-Madison, 53706-1596, USA. sbcarrol@facstaff.wisc.edu
Nature
|March 10, 2001
Summary
Life on Earth evolved from simple microbes to complex multicellular organisms over billions of years. Modular construction aided this growth, but large, mobile life may not be universal.
Area of Science:
- Astrobiology and Evolutionary Biology
- Investigates the evolutionary trajectory of life on Earth to inform the search for extraterrestrial life.
Background:
- Life on Earth was predominantly microscopic for its first three billion years.
- The last 600 million years have seen a dramatic increase in organism size, complexity, and diversity, transforming the biosphere.
Purpose of the Study:
- To analyze evolutionary trends on Earth.
- To determine if the evolution of large, complex, and modular organisms is a universal biological pattern.
Main Methods:
- Comparative analysis of evolutionary trends across different life forms on Earth.
- Examination of key biological innovations, such as modular construction.
Main Results:
- Life's evolution on Earth shows distinct phases: a long period of microbial dominance followed by rapid diversification of macroforms.
- Modular construction is a significant factor in the increase of size, complexity, and diversity in plants and animals.
- The emergence of motile, modular mega-organisms may not be a universal outcome of life's evolution.
Conclusions:
- Earth's evolutionary history provides a framework for understanding potential life elsewhere.
- While simple life forms might be common, the development of complex, large-scale organisms like animals and plants may be contingent on specific evolutionary pathways, such as modularity.
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