Michel Laurin
- Published in print:
- 2010
- Published Online:
- March 2012
- ISBN:
- 9780520266476
- eISBN:
- 9780520947986
- Item type:
- chapter
- Publisher:
- University of California Press
- DOI:
- 10.1525/california/9780520266476.003.0004
- Subject:
- Biology, Evolutionary Biology / Genetics
To understand the colonization of land by vertebrates, this chapter studies the origin and evolution of limbs, and especially of their skeleton, first examining the vertebrate skeleton, and then ...
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To understand the colonization of land by vertebrates, this chapter studies the origin and evolution of limbs, and especially of their skeleton, first examining the vertebrate skeleton, and then discussing the study of the origin of digits using Hox gene expression patterns in limb or fin buds. It also examines the study of sarcopterygian fins and the origin of digits using molecular developmental data. The gills of Acanthostega and the original function of the tetrapod limb are also examined. Finally, the chapter discusses the use of bone microanatomy to infer the lifestyle of early stegocephalians.Less
To understand the colonization of land by vertebrates, this chapter studies the origin and evolution of limbs, and especially of their skeleton, first examining the vertebrate skeleton, and then discussing the study of the origin of digits using Hox gene expression patterns in limb or fin buds. It also examines the study of sarcopterygian fins and the origin of digits using molecular developmental data. The gills of Acanthostega and the original function of the tetrapod limb are also examined. Finally, the chapter discusses the use of bone microanatomy to infer the lifestyle of early stegocephalians.
Frederick R. Schram and Stefan Koenemann
- Published in print:
- 2021
- Published Online:
- January 2022
- ISBN:
- 9780195365764
- eISBN:
- 9780197521854
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195365764.001.0001
- Subject:
- Biology, Aquatic Biology
The understanding of arthropod phylogeny and evolution in the past three decades has undergone major changes. These have arisen from new sources of data applicable across several fields of study. ...
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The understanding of arthropod phylogeny and evolution in the past three decades has undergone major changes. These have arisen from new sources of data applicable across several fields of study. Developments within ontogenetic studies not only in regard to gross patterns of embryology but also regarding a revolution in the application of development genetics continue to generate remarkable insights into crustaceomorph evolution. Phylogeny techniques of analysis and new sources of data derived from molecular sequencing have forced consideration of new hypotheses concerning the interrelationships of all the pancrustaceans, both crustaceomorphs and Hexapoda. Furthermore, it is not uncommon that this multiplicity of sources for new data from opposing research teams can result in different hypotheses for phylogenetic relationships. This situation should not be treated as a defect, or an impediment, but rather as a source for multiple alternative hypotheses—the bases for further data gathering and analyses. Also, one should never view consideration of fossils as a vexing source of noise. Here, too, consideration of multiple hypotheses has proven useful. Often, fossils can produce deeper understanding of the paleodiversity of body plans. Nevertheless, some fossil groups still remain as enigmas, such as Thylacocephala. But even fossils incompletely understood can help fill in gaps in knowledge of paleobiodiversity that can prove useful, for example, in analyzing the the origin and early evolution of Hexapoda. Old ideas about pancrustacean evolution have served the field well, but results derived from all data inputs should be embraced.Less
The understanding of arthropod phylogeny and evolution in the past three decades has undergone major changes. These have arisen from new sources of data applicable across several fields of study. Developments within ontogenetic studies not only in regard to gross patterns of embryology but also regarding a revolution in the application of development genetics continue to generate remarkable insights into crustaceomorph evolution. Phylogeny techniques of analysis and new sources of data derived from molecular sequencing have forced consideration of new hypotheses concerning the interrelationships of all the pancrustaceans, both crustaceomorphs and Hexapoda. Furthermore, it is not uncommon that this multiplicity of sources for new data from opposing research teams can result in different hypotheses for phylogenetic relationships. This situation should not be treated as a defect, or an impediment, but rather as a source for multiple alternative hypotheses—the bases for further data gathering and analyses. Also, one should never view consideration of fossils as a vexing source of noise. Here, too, consideration of multiple hypotheses has proven useful. Often, fossils can produce deeper understanding of the paleodiversity of body plans. Nevertheless, some fossil groups still remain as enigmas, such as Thylacocephala. But even fossils incompletely understood can help fill in gaps in knowledge of paleobiodiversity that can prove useful, for example, in analyzing the the origin and early evolution of Hexapoda. Old ideas about pancrustacean evolution have served the field well, but results derived from all data inputs should be embraced.
