sister groups

Why Is An Outgroup Important?

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Why Is An Outgroup Important? The outgroup is used as a point of comparison for the ingroup and specifically allows for the phylogeny to be rooted. Because the polarity (direction) of character change can be determined only on a rooted phylogeny, the choice of outgroup is essential for understanding the evolution of traits along a

Do Sister Groups Always Form A Clade?

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Do Sister Groups Always Form A Clade? Do sister groups always form a clade? Note that some evolutionary trees don’t include an outgroup. 2=Sister groups: Sister groups are two clades that are each others’ closest relatives. On a phylogeny, sister groups occur anytime a single ancestral lineage gives rise to two separate lineages: those two