×
Please click
here
if you are not redirected within a few seconds.
All
Images
Books
Videos
Maps
News
Shopping
Search tools
Any time
Any time
Past hour
Past 24 hours
Past week
Past month
Past year
All results
All results
Verbatim
Evolutionary grade
A grade is a taxon united by a level of morphological or physiological complexity. The term was coined by British biologist Julian Huxley, to contrast with clade, a strictly phylogenetic unit.
Wikipedia