Phylogenetic Trees and Evolutionary Relationships

Flashcards covering key vocabulary terms and concepts from a lecture on phylogenetic trees, sexual selection, and related evolutionary biology topics.

Taxonomy

The branch of biology concerned with naming, describing, and classifying organisms.

Phylogeny

The evolutionary history of a group of organisms, often represented graphically using phylogenetic trees.

Branch

A line representing a species or group over time in a phylogenetic tree.

Node

Where a branch splits in a phylogenetic tree, representing the most recent common ancestor of the descendant groups.

Branch Tip

A single taxon at the end of a branch in a phylogenetic tree; may be living or extinct.

Root

The most ancestral branch on a phylogenetic tree.

Sister Groups

Lineages that share a recent common ancestor at the node where their branches meet.

Ancestral Trait

A trait that is present in the ancestors of a particular group.

Derived Trait

A trait that is a modified form of an ancestral trait, found only in a descendant.

Synapomorphy

A shared, derived trait present in a recent common ancestor, but missing in more distant ancestors.

Parsimony

The idea that the simplest explanation is most likely correct; used in constructing phylogenetic trees.

Homology

Similarity among organisms of different species due to shared ancestry.

Homoplasy

Similarity among organisms due to reasons other than common ancestry.

Convergent Evolution

The independent evolution of similar traits in different species due to adaptation to similar environmental conditions and a similar way of life.

Monophyletic

An evolutionary unit including an ancestral population, all of its descendants, and no others.

Paraphyletic

A group including an ancestral population and some of its descendants, but not all of them.

Polyphyletic

A group of organisms that includes taxa that do not share a most recent common ancestor.

Direct Benefit

Choosing partners that provide resources to have more or better offspring