cladistics
Tags
bio/eco
cegep/3
Word count
119 words
Reading time
1 minute
Approach to taxonomy in which species are placed in clades
Steps:
- Select an outgroup (taxon known to have diverged before the group in study,
ant.ingroup). - Select derived characters.
E.g.for flowers:- Clear distinction between sepal and petal
- Fusion petals
- Type of venation (reticulate vs parallel) of leaf
- Position of gynoecium
- Angle between petals
- Make a matrix of presence of characters in the groups.
- Construct the phylogenetic tree based on common characters.
- Maximum parsimony favours the simplest tree (with the least character state changes).
- Maximum likelihood favours the tree most likely to have produced the different DNA sequences.
Ajitani Hifumi