Chapter 20 - phylogenetic trees

rate of evolutionary change

1 base per 25 million years

total time of divergence

number of differences x mutation rate

time since divergence

total time of divergence/2

taxonomy

the study of classifying lfie

binomial naming

genus, species

taxonomic order

kingdom, phylum, class, order, family, genus, species

taxon

any group on the hierarchy

branch point

where species diverge

evolutionary lineage

a sequence of organisms leading to a specific descendant, represented by the branches

sister taxa

shares an immediate ancestor not shared by any other group

rooted

represents the mcra of all taxa in the tree

basal taxon

a lineage that diverges early in the history of a group

analogy

similarity due to convergent theory

homology

similarity due to ancestry

systematics

study of the diversity of life

cladistics

using clades to approach systematics

clade

a branch that includes a single ancestor and all its descendants

monophyletic clades

one common ancestor and all of its descendants from one branch point

paraphyletic ancestor

sister taxa + nonsister from the same branch

polyphyletic

includes taxa from different branches

shared ancestral character

a character that originated in an ancestor of the taxon

derived ancestral trait

those that just appeared (by mutation) in the most recent ancestor

outgroup

closely related but not part of the group of species being studied

ingroup

species being studied

maximum parsimony

applying the simplest, most obvious way with the least number of steps

molecular clock

uses comparisons of DNA sequences to estimate phylogeny and rate of evolutionary change

rate of evolutionary change

1 base per 25 million years