Zoology Chapter 12`

Diversity of Life

phylogeny

describes the evolutionary history and relationships among organisms

phylogenetic tree

Represents a hypothesis about the evolutionary relationships among organisms

The proximity of organisms’ names do not indicate closeness of relationships

the most parsimonious tree

branch point (node)

represents a common ancestor from which two or more lineages diverge

trace the branches backwards until the paths meet at a node

how to find the most recent common ancestor on a phylogeny tree

clade

monophyletic group

a common ancestor and all of its descendants

a groups consisting of a single common ancestor and all of its descendants, forming one branch

maximum parisomy

favors the hypothesis requiring the fewest evolutionary changes

systematics

the study of evolutionary relationships among ancestors

LUCA- last universal common ancestor

explains why all life shares fundamental molecular machinery, like the geneti code

root of the tree of life

homologous characteristics

similarity due to common ancestry

similarity in structure, difference in function

ex: human arm, whale flapper, bat forelimb

analogous characteristicss

similarities due to convergent evolution

similarity in function not structure

shared ancestral characteristics

cahracteristic that orginated before the group being examines

shared derived characteristics

a trait that evolved in a common ancestor and is present in all its descendants, distinguishing them from other organisms

a feature from the common ancestor of a small group can be derived relative to a broader comparison

how can the same characteristic be ancestral in one comparison and derived in another

molecular clock

method for estimating when lineages derived

molecular systematics

Use of molecular data to determine evolutionary relationships

More sequence similarity generally supports a more recent common ancestor

DNA, RNA, and Amino Acid sequence of proteins

it reflects the inheritance of genetic info from shared ancestores

how can similarities in DNA and protein sequences tell us about common ancestry