Lecture 23: Organ/Phylogeny

Flashcards for key vocabulary and concepts related to phylogenetics covered in BIOL 204.

Phylogenetic Tree

A tree-like diagram that represents the evolutionary relationships among various biological species based on their characteristics and ancestry.

Synapomorphy

A trait that is shared by two or more taxa and was present in their most recent common ancestor.

Homologous Traits

Traits that are similar due to shared ancestry, as opposed to analogous traits, which arise independently due to convergent evolution.

Convergence

The phenomenon where distantly related species evolve similar traits because of similar environmental selection pressures.

Divergence

The process in which closely related species evolve different traits as a result of selection by different environments.

Parsimony

The principle in phylogenetics that favors the arrangement of taxa that requires the fewest changes, making it the most likely arrangement.

Character State

The observed state of a character used in phylogenetic tree-building, such as the presence or absence of a trait.

Outgroup

A lineage that falls outside the clade being studied but is closely related, used to help identify shared traits within the clade.

Molecular Clock

The concept that DNA mutations accumulate at a relatively constant rate over time, allowing estimation of the time since lineages diverged.

LINEs (Long Interspersed Nuclear Elements)

Transposable elements in eukaryotic genomes, making up a significant portion of the human genome and playing a role in genomic evolution.

SINEs (Short Interspersed Nuclear Elements)

Transposable elements that require LINE enzymes for replication, contributing to genetic variation and evolution.