Entire Set of Printable Figures For
Evolution of the Avian Visual System - Husband & Shimizu
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Homoplastic rather than homologous.
In discussing traits of the ancestral amniote brain, and how it has subsequently changed through evolution, a distinction is made between homology and homoplasy. Characteristics which appear similar in structure and/or function in two organisms may derive from the condition of the presumed ancestor of the two forms. This is referred to as homology, which has been defined by Campbell and Hodos (1970): "(structures and characters) are homologous when they could, in principle, be traced back through a genealogical series to a stipulated common ancestral precursor irrespective of morphological similarity."
Link to Archaeopteryx web site
Link to Jurassic Park web site.
Link to The Lost World web site.
Link to Velociraptor picture at The Lost World web site.