Phylogenies and Evolution

These flashcards cover key vocabulary and concepts related to phylogenies and the evolution of life, providing definitions and explanations necessary for understanding these topics.

Phylogenetic tree

Diagrams used to reflect evolutionary relationships among organisms, or a group of organisms, or among genes.

Tips (or Terminals)

The end of the branch on a phylogenetic tree, representing species or groups of species.

Branches

Represent changes that have occurred over time in a phylogenetic tree.

Nodes (or branching points)

Points in a phylogenetic tree that represent ancestors and speciation events.

Relatedness

Recency of a common ancestor; represented on the tree through nodes.

Clade

A group that includes an ancestor and all its descendants.

Monophyletic group

A group that includes the common ancestor and all the descendants.

Paraphyletic group

Includes a common ancestor and some, but not all, of its descendants.

Polyphyletic group

Does not include the common ancestor.

Sister groups

Two descendants that arise from the same node and share a most recent common ancestor.

Homology

Genotypic or phenotypic similarities due to shared ancestry.

Analogy

Similar traits that are derived from different structures.

Convergent evolution

Evolution where different species arrive at similar traits independently.

Shared derived characters

Evolutionary novelties unique to a clade, used to infer phylogenies.

Prokaryotic cell

Cells that are unicellular, have circular chromosomes, and lack a nucleus.

Eukaryotic cell

Cells characterized by the presence of a nucleus, endomembrane system, and membrane-bound organelles.

Ploidy

Number of chromosome sets in the nucleus of a cell.

Haploid

A cell with one set of chromosomes (1n).

Diploid

A cell with two sets of chromosomes (2n).

Mitosis

Cell division resulting in daughter cells with the same number of chromosomes as the parent cell.

Meiosis

Cell division that reduces the chromosome number by half to form haploid gametes.