Lab 2 Systematics o The study of evolutionary relationships among organisms o Develops hypothetical models phylogenies Phylogenies o that reconstruct the evolutionary history of organisms based on common ancestry Taxon taxonomy o Practice of naming and classifying organisms o A named group at any level Levels of taxonomic classification o KFCOFGS o DSGSFGS Monophyletic o Clades o Consist of an ancestor and all of its descendants Paraphyletic o Not clades taxa o An ancestor and some but not all of its descendants Polyphyletic o Taxa o More than one ancestor Foundation concepts of the Theory of Evolution o Cell theory States that organisms consist of one or more cells and that cells are capable of replication o Gene theory Holds that DNA coded in genes contains the blueprint for protein expression and that proteins are the foundation for cellular structure and function o Theory of Inheritance States that the genetic code may be changes through mutation or crossing over during meiosis Reduction division and that segregation and independent assortment or chromosomes during meiosis permits unique combinations of genes to be inherited by individuals 7 areas that provide evidence of evolution o Fossil record Transitional fossils have characteristics of both ancestral and descendent lineages Help us understand the function of traits and the order in which they evolved Help establish the probable evolutionary relationships of organisms o Biogeography The study of the geographical distribution of biological organisms o Homology and relatedness of form Structures derived from the same body part of a shared ancestor o Vestigial traits Structures that have no apparent function provide evidence of species change and clues to evolutionary relationships o Developmental similarities The stages of embryological development may provide clues to common descent o Molecular genetics Evidence for common ancestry and species change over time is provided by mapping the differences in proteins DNA sequences and specific genes between organisms o Observation of evolutionary change Darwin Theory of evolution o States that biodiversity is the result of natural processes Cladogram o Constructed by examining clusters of shared derived character states synapomorphies and comparing them to an out group A related group that is not part of the group under study o Branching diagrams where each branch point or node indicates a bifurcating event in evolutionary history o Diagram classifying species into hierarchical groups based on shared derived character states Analogous structures o Structure with the same function but different structure Parsimony o Adoption of the simplest assumption in the formulation of a theory or in the interpretation of data Plesiomorphy o Ancestral condition Apomorphy o Derived character not present in ancestor o Homologous to the ancestral character Autapomorphy o A derived character unique to a taxon Synapomorphy o A derived character shared by a set of taxa
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