Systematics

    Cards (33)

    • Systematics
      Study of the diversity of life forms and the evolutionary relationships of organisms
    • Systematics
      • Systematists use data from fossils to molecules to genes to infer evolutionary relationships and reconstruct the Tree of Life
    • Cladogram
      Shows evolutionary relationships of organisms
    • Phylogeny
      Evolutionary history of a species or a group of species
    • Phylogenetic Tree

      An extensive and more detailed cladogram
    • Systematics is the study of the kinds and diversity of organisms and of any and all relationships among them
    • Tracing phylogeny is one of the goals of systematics; hence, it is considered as the study of biological diversity in an evolutionary context
    • Systematists use data ranging from fossils to molecules and genes to infer evolutionary relationships
    • These information enable biologists to construct a comprehensive tree of life that will continue to be refined as additional data are collected
    • The Tree of Life is a model and a phylogenetic tree that shows the evolutionary relationships of all organisms, backed by evidences, from fossil, behavioral, molecular, and morphological data
    • Lines of evidence to infer evolutionary relationships
      1. Fossil evidence
      2. Homologies
    • Homologies
      Similar characters due to relatedness are known as homologies
    • Homologies can be revealed by comparing the anatomies of different living things, looking at cellular similarities
    • Taxonomy is the science that deals with classification, naming, and identification of organisms
    • Classification - grouping of organisms into categories based on similarities and differences
    • Nomenclature - assigning names to taxa (groups) according to rules
    • Lines of evidence to infer evolutionary relationships
      • Fossil evidence
      • Homologies
      • Molecular homology
      • Developmental biology
      • Biogeography
      • Molecular clocks
      • Classification linked to phylogeny
    • Similar characters due to relatedness are known as homologies
    • Ways to reveal homologies
      • Comparing the anatomies of different living things
      • Looking at cellular similarities and differences
      • Studying embryological development
      • Studying vestigial structures within individual organisms
    • Molecular comparisons may reveal mutations
    • Measuring the degree of similarities in a molecular level can be achieved by the latest software technologies, while physically, some differences can be unnoticeable
    • Studying the embryological development of living things provides clues to the evolution of present-day organisms
    • During some stages of development, organisms exhibit ancestral features in whole or incomplete form
    • Biogeography involves the geographic distribution of species in time and space as influenced by factors such as Continental Drift and long-distance dispersal
    • Molecular clocks help track evolutionary time
    • The base sequences of some regions of DNA change at a rate consistent enough to allow dating of episodes in past evolution
    • Other genes change in a less predictable way
    • The connection between classification and phylogeny is that hierarchical classification is reflected in the progressively finer branching of phylogenetic trees
    • The branching patterns in some cases match the hierarchical classification of groups nested within more inclusive groups
    • In some situations, certain similarities among organisms may lead taxonomists to place a species within a group of organisms other than the group to which it is closely related
    • Biologists care about phylogenies because species' phylogeny provides an enormous amount of information
    • Identification - determining which species or higher category a particular specimen belongs to
    • Classifying living things involves identifying their characteristics and placing them into categories based on those characteristics
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