Via 100 entries or "mini-chapters," 21st Century Anthropology: A Reference Handbook highlights the most important topics, issues, questions, and debates any student obtaining a degree in the field of anthropology ought to have mastered for effectiveness in the 21st century. This two-volume set provides undergraduate majors with an authoritative reference source that serves their research needs with more detailed information than encyclopedia entries but in a clear, accessible style, devoid of jargon, unnecessary detail or density.Key Features- Emphasizes key curricular topics, making it useful for students researching for term papers, preparing for GREs, or considering topics for a senior thesis, graduate degree, or career.- Comprehensive, providing full coverage of key subthemes and subfields within the discipline, such as applied anthropology, archaeology and paleontology, sociocultural anthropology, evolution, linguistics, physical and biological anthropology, primate studies, and more.- Offers uniform chapter structure so students can easily locate key information, within these sections: Introduction, Theory, Methods, Applications, Comparison, Future Directions, Summary, Bibliography & Suggestions for Further Reading, and Cross References.- Available in print or electronically at SAGE Reference Online, providing students with convenient, easy access to its contents.
Chapter 39: Twin Studies
Studying twins offers a unique opportunity to identify and differentiate physical and behavioral characteristics according to their origin. How much of who we are is genetically determined and how much is the result of our environment? By comparing the consistency of phenotypes, that is, observable physical and behavioral characteristics, in twins we can hypothesize about their heritability-whether or not a specific characteristic is genetically determined. Based on the assumption that all twins share their environment and that monozygotic twins also share genomes, phenotypes that vary between monozygotic twins must be the result of environmental factors, while those that are consistently the same must be genetic in origin.
Though they must be inextricably linked, there is a difference between research on twins and research ...