Phylogeny and the Tree of Life

A set of practice flashcards covering key concepts from the lecture on phylogeny and the tree of life.

What defines a phylogeny?

The evolutionary history of a species or group of related species.

What is systematics?

A discipline focused on classifying organisms and determining their evolutionary relationships.

What are the two key features of Linnaeus's system of taxonomy?

Two-part names for species and hierarchical classification.

What is a binomial?

The two-part scientific name of a species, consisting of the genus and specific epithet.

What are the main taxonomic groups in Linnaeus's hierarchical classification?

Domain, kingdom, phylum, class, order, family, genus, and species.

What is a taxon?

A group at any level of hierarchy in taxonomy.

What is a phylogenetic tree?

A branching diagram representing the evolutionary history of a group of organisms.

What is homology?

Similarity in characteristics due to shared ancestry.

What distinguishes homology from analogy?

Homology is due to shared ancestry, while analogy arises from convergent evolution.

What are clades in cladistics?

Groups of species that include an ancestral species and all its descendants.

What is a shared ancestral character?

A character that originated in an ancestor of the taxon.

What is the role of an outgroup in phylogenetic studies?

To help differentiate between shared derived and shared ancestral characters.

What does a molecular clock estimate?

The absolute time of evolutionary change based on genetic changes.

What are orthologous genes?

Homologous genes that are a result of a speciation event and occur between different species.

What are paralogous genes?

Homologous genes that result from gene duplication within a species.

What is the significance of horizontal gene transfer?

It allows movement of genes between organisms, influencing evolutionary relationships.

Why has the classification of life changed from two kingdoms to three domains?

To better reflect the genetic and evolutionary relationships among organisms.