Abstract:Abstract Chordata, our own lineage (fig. 23.1), belongs to the successively more inclusive clades Deuterostomata, Bilateria, Metazoa, and so forth. The organization of chordates is distinctively diffe...Abstract Chordata, our own lineage (fig. 23.1), belongs to the successively more inclusive clades Deuterostomata, Bilateria, Metazoa, and so forth. The organization of chordates is distinctively different from that of its metazoan relatives, and much of this distinction is conferred by unique mechanisms of development (Slack 1983, Schaeffer 1987). Throughout chordate history, modulation and elaboration of developmental systems are persistent themes underlying diversification. Only by understanding how ontogeny itself evolved can we fully apprehend chordate history, diversity, and our own unique place in the Tree of Life. My goal here is to present a contemporary overview of chordate history by summarizing current views on relationships among the major chordate clades in light of a blossoming understanding of molecular, genetic, and developmental evolution, and a wave of exciting new discoveries from deep in the fossil record. Chordates comprise a clade of approximately 56,000 named living species that includes humans and other animals with a notochord—the embryological precursor of the vertebral column. Chordate history can now be traced across at least a half billion years of geological time, and twice that by some estimates (Wray et al. 1996, Ayala et al.Read More
Publication Year: 2004
Publication Date: 2004-07-22
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 12
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