Final answer:
A clade, in biological classification, includes an ancestor and all of its descendants, and is identified using cladistics. Cladograms visually depict these relationships with branch points indicating divergence. All members of a clade share a single point of origin in their phylogeny.
Step-by-step explanation:
A clade is a group of organisms that consists of an ancestor and all of its descendants. This concept is a key part of phylogenetic classification, which is concerned with the evolutionary relationships among species. Clades are determined by using a method called cladistics, which involves comparing traits in related species to deduce those relationships.
Cladograms are branching diagrams used to represent the evolutionary pathways and connections between organisms, where each branch denotes the emergence of new characteristics that separate one group of organisms from another, thereby forming a clade. Within a cladogram, a branch point signifies where a lineage splits into distinct new groups.
An important feature of a clade, also known as a monophyletic group, is that all members stem from a single point of divergence on the tree of life. The term 'monophyletic' breaks down into 'mono' meaning one, and 'phyletic' meaning evolutionary relationship, which emphasizes the singular ancestral origin of the clade.