Phylogenetic Trees & Collatagram

What are the ways to establish phylogenetic relationships between organisms?

- Compare DNA.RNA sequences of specific genes - Compare the amino acid sequences of specific proteins - Compare morphology/shared derived traits - Molecular data

A group of biological taxa (such as a species) that includes all descendants of one common ancestor.

Clade

A common ancestor and all of its descendants (i.e. the node and all of its connected branches)

Clade/Monophyletic Group

These do not show time. They are used to illustrate evolutionary relationships among relationships. Each node has two branching lines of descendance, indicating evolutionary divergence from a common ancestor. It is a type of Phylogenetic Tree.

Cladograms

A trait that is present in an organism/group/lineage, but was absent in the last common ancestor of the group being considered.

Derived Trait/Derived Characater

THe group of related species that are beig studied/depicted by the Cladogram.

Ingroup

A branch of biology dealing with the study of the form and structure of organisms and their specific structural features.

Morphology

Each of these corresponds to a hypothetical common ancestor that speciated to give rise to two daughter taxa.

Node

This is a group of organisms that serves as a reference group when determining the evolutionary relationships of the ingroup. This represents the lineage/group that is least closely related to the remainder of the organisms.

Outgroup

Each node, or point of divergence, has two branching lines of descendance, indicating evolutionary divergence from a common ancestor. These are drawn like a branching tree in which branch length is proportional to the evolutionary distance/time between organisms.

Phylogenetic Tree

The history of the evolution of a species or group, especially in reference to lines of descent and relationships among broad groups of organisms.

Phylogeny

The initial ancestor common to all organisms within the cladogram. This is the point which begins the Cladogram.

Root

A trait shared by a group of organisms as a result of descent from a common ancestor.

Shared Ancestral Trait

Phylogenetic trees and cladograms represent __________ and are constantly being revised based on newly acquired evidence. They are NOT consistently accurate over time.

hypotheses