Wednesday, 5 July 2017

SYNAPOMORPHY ,SYMPLESIOMORPHY ,APOMORPHY ,PLESIOMORPHY AND HOMOPLASY

All these terms have to do with identifying organisms, called taxa, into "family trees", according to identifying traits or characteristics.

Synapomorphy: a trait share by 2 or more taxa and their most recent common ancestor.

Symplesiomorphy : A characteristic shared by 2 or more taxa also found in their earliest common ancestor.

Apomorphy: A characteristic believed to have evolved within a family tree; can be used to separate one group from the other.

Plesiomorphy-plesiomorphy refers to the ancestral trait state, usually in reference to a derived trait state.

All these terms provide valuable information, depending on how one is constructing the family tree or taxa. The first two, synapomorphy and symplesiomorphy, provide evidence among similarities between recent taxa and their ancestors. Apomorphy distinguishes differences between recent taxa and their ancestors, providing a breaking-off point that could be used to establish new groups or sub-groups.
 Homoplasy is a character shared by a set of species but not present in their common ancestor. A good example is the evolution of the eye which has originated independently in many different species. When this happens it is sometimes called a convergence.
Image result for plesiomorphy
                               Image source credit goes to -http://slideplayer.com/slide/3525255/
CSIR PART C-QUESTION
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CORRECT OPTION IS 2 As Synapomorphy: a trait share by 2 or more taxa and their most recent common ancestor in that case resin canal should be present  in the ancestor as it is pinacea  family .

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