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7: Phylogenies and the History of Life

  • Page ID
    69835
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    Learning Objectives
    • Introduce classification systems

    • Describe how systematics and taxonomy relate to phylogeny

    • Discuss the components, purpose, and important concepts regarding phylogenetic trees

    • Discuss the purpose of cladistics

    • Discuss horizontal gene transfer and going beyond the phyologenetic tree

    • 7.1: Introduction
      This bee and Echinacea flower could not look more different, yet they are related, as are all living organisms on Earth.
    • 7.2: Organizing Life on Earth
      In scientific terms, the evolutionary history and relationship of an organism or group of organisms is called phylogeny. Phylogeny describes the relationships of an organism, such as from which organisms it is thought to have evolved, to which species it is most closely related, and so forth. Phylogenetic relationships provide information on shared ancestry but not necessarily on how organisms are similar or different.
    • 7.3: Determining Evolutionary Relationships
      Scientists must collect accurate information that allows them to make evolutionary connections among organisms. Similar to detective work, scientists must use evidence to uncover the facts. In the case of phylogeny, evolutionary investigations focus on two types of evidence: morphologic (form and function) and genetic.
    • 7.4: Perspectives on the Phylogenetic Tree
      The concepts of phylogenetic modeling are constantly changing. It is one of the most dynamic fields of study in all of biology. Over the last several decades, new research has challenged scientists’ ideas about how organisms are related. New models of these relationships have been proposed for consideration by the scientific community.
    • 7.5: A Brief History of Life on Earth

    Summary

    By following pathways of similarities and changes—both visible and genetic—scientists seek to map the evolutionary past of how life developed from single-celled organisms to the tremendous collection of creatures that have germinated, crawled, floated, swam, flown, and walked on this planet.

    Contributors and Attributions

    • Connie Rye (East Mississippi Community College), Robert Wise (University of Wisconsin, Oshkosh), Vladimir Jurukovski (Suffolk County Community College), Jean DeSaix (University of North Carolina at Chapel Hill), Jung Choi (Georgia Institute of Technology), Yael Avissar (Rhode Island College) among other contributing authors. Original content by OpenStax (CC BY 4.0; Download for free at http://cnx.org/contents/185cbf87-c72...f21b5eabd@9.87).


    7: Phylogenies and the History of Life is shared under a CC BY-NC-SA license and was authored, remixed, and/or curated by LibreTexts.

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