GEN BIO 2 | Phylogeny

Note: does not include notes on morphology, which can be found in the evidences of evolution flashcards

Phylogeny

evolutionary history of a species or a group of species

Phylogenetic Tree

a diagram that indicates common ancestors and lines of descent or lineages, displaying evolutionary relationships`

Cladistics

a phylogenetic system that defines groups by distinguishing between ancestral and derived characteristics

Ancestral Characters

inherited attributes that resemble those of an ancestor of a group

Derived Characters

features different from those found in the group’s ancestor, one that distinguishes them from other species

How to identify derived and ancestral traits

choose an outgroup consisting of a comparator organisms that are not part of the group being studied

Cladogram

treelike diagram built using shared derived characters

Root

initial ancestor common to all the organisms

Node

a common ancestor that speciated to give rise to multiple daughter taxa

Outgroup

most distantly related species and functions as a reference group

Clade

it is monophyletic, meaning a “single tribe”; containing a single common ancestor and all descendants

Paraphyletic

“beside the tribe” a common ancestor and some of its descendants

Polyphetic

“many tribes”; a grouping with no recent common ancestor

DNA Sequence Comparisons

DNA sequences of a small section of a gene are aligned to determine the evolutionary relationships among some mammals

Protein Sequence Comparison

the number of differences on the amino acid sequence among several species are used as a measure of relative relatedness

Constructing Cladograms

1. Create a table listing the characteristics of the organisms.

2. Sequentially order organisms according to shared characteristics to construct a cladogram.