Brains Through TimePub Date : 2019-12-05DOI: 10.1093/oso/9780195125689.003.0001
G. Striedter, R. Northcutt
{"title":"Reconstructing History","authors":"G. Striedter, R. Northcutt","doi":"10.1093/oso/9780195125689.003.0001","DOIUrl":"https://doi.org/10.1093/oso/9780195125689.003.0001","url":null,"abstract":"This introductory chapter describes the book’s general approach and underlying philosophy. The authors adopt a definition of biological homology that recognizes the hierarchical nature of biological organization and allows for any aspects of a character to change over the course of evolution. The only essential homology criterion is that the characters in question must have been retained from a common ancestor, rather than having evolved independently in multiple lineages. These fundamental ideas are discussed in the context of related concepts, notably “field homology” and the homology of cell types and developmental pathways. Although it is easy to get tangled up in questions about the homology or non-homology of individual characters, the book’s main concern is the evolution and natural history of entire organisms and the lineages to which they belong.","PeriodicalId":182534,"journal":{"name":"Brains Through Time","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116751862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Brains Through TimePub Date : 2019-12-05DOI: 10.1093/oso/9780195125689.003.0002
G. Striedter, R. Northcutt
{"title":"The Origin of Vertebrates","authors":"G. Striedter, R. Northcutt","doi":"10.1093/oso/9780195125689.003.0002","DOIUrl":"https://doi.org/10.1093/oso/9780195125689.003.0002","url":null,"abstract":"Some time in the Ediacaran or early Cambrian period, the first vertebrates emerged. Compared to the invertebrate chordates, early vertebrates were active predators, rather than suspension feeders. This change in behavior was facilitated by several major morphological innovations, including pharyngeal muscles that pump water through the pharynx, vascularized gills, paired image-forming eyes, a complex vestibular apparatus, lateral line receptors, taste buds, and a well-developed olfactory system. Early vertebrates also evolved several new brain regions, notably the telencephalon and the midbrain. Developmentally, most of these innovations were linked to the emergence of two novel embryonic tissues, namely placodes and neural crest. Although these tissues and their adult derivatives did not evolve “out of nothing,” they represent genuine innovations that contributed substantially to the evolutionary success of the vertebrate lineage.","PeriodicalId":182534,"journal":{"name":"Brains Through Time","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127887699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}