Classification, Systematics, Taxonomy, Phylogeny basics and terms

Homology

The state of having the same or similar relation, relative position, or structure

Homoplasy

The independent evolution of similar traits in different species, meaning they appear similar but are not due to a shared ancestry

Synapomorphy

a shared, derived trait that indicates a common ancestry among a group of organisms

Plesiomorphy

an ancestral trait shared by a broader group, including the group of interest

Convergent Evolution

The independent evolution of similar traits in distantly related species or lineages, driven by similar selective pressures in their environment

Outgroup

A group of organisms not belonging to the group whose evolutionary relationships are being investigated

Monophyletic

A group of organisms that includes a common ancestor and all of its descendants

Paraphyletic

A common ancestor but not all of its descendants

Polyphyletic

Does not share a common ancestor and includes organisms that have evolved similar traits independently

General features and taxa of Lophotrochozoan and Ecdysozoa

Lophotrochozoan includes phyla with trochophore larvae and/or lophophores, while Ecdysozoa is defined by ecdysis.

Relative abundances of major taxa

How common or rare a species is compared to other species in a given location of community