18.2 modern evolutionary classification
what were the problems with traditional classification?
scientists relied on body structure, and the problem was that very different organisms evolved with similair structures making the classification hard
how do scientists classify organisms now?
they group with similar lines of evolutionary history
species place within the same genus
should be more closely related to one another than to species of any other genus
grouping organisms together based on their evolutionary history
characteristics that appeared in recent parts of the lineage but not in the older ones
shows evolutionary relationships between organisms
uses DNA comparisons to estimate the length of time that 2 species have been evolving independent