Cladistics

Cladistics

study of evolutionary trees

Clade

a group of organisms that have evolved from a common ancestor

How is a clade presented and how is it used?

presented on one branch (clade) and is used to analyze relationships between organisms

Cladogram

diagram created showing an evolutionary tree

What are the parts of a cladogram?

root, node, and terminal branches/ends

Root

single point that represents the common ancestor

Node

branching point

Terminal branches/ends

tips of branches representing a single species

What are the three evidence types that is used to make clades?

-genetic N base sequences (DNA, RNA, mDNA)

-amino acid sequences of proteins

-derived traits/structures/morphology (older versions)

What is a more modern method of gaining evidence for clades?

genetic material and amino acids

“Molecular clock”

gives estimates of mutation rate

What is the molecular clock affected by?

-length of generation time

-intensity of selection pressures

-size of population

What can the molecular clock show?

That organisms have been classified incorrectly and are more related to a different species

Draw an example of a cladogram

A

Time

B

Most common ancestor

C

shared ancestral lineage

D

common ancestor

E

node

F

terminal ends

G

descendent lineage