Comparative Anatomy - Chapter 1 Terms

Morphology

The study of anatomy and its significance (its form and structure)

Functional Morphology

Discipline that relats a structure to its function

Archetype

make up or model of an organism

Primitive

relating to, denoting, or preserving the character of an early stage in the evolutionary or historical development of something

Derived

from ancestral forms through evolution; indicates a later stage in evolutionary development.

Vertebrate Morphology

the study of the form and structure of vertebrate animals, focusing on their anatomical features and evolutionary relationships.

Ontogeny

dealing with the development of an organism

Homology

features in different organisms that are similar because of common ancestry

Analogy

features in different organisms that are similar function (but not necessarily due to common ancestry

Homoplasy

features in different organisms that look alike

Radial Symmetry

if cut in any way, pieces are identical

Bilateral Symmetry

mirrored image if split in half

Segmentation

process that divides the bod into duplicated sections

Evolutionary Morphology

function of a structure but also its role in adaptation

Function

the action or property of a part as it works in the organism

Biological Role

how the part is used in the environment during the organism’s lifetime

Phylogeny

evolutionary history of a group of organisms (species)

Phylogenic tree; Dendrogram; Tree of Life

relationships of a group in the form of a branching tree

Character

physical feature of an organism

Character State

the condition or type of character

Plesiomorphic trait

the earlier (ancestral) state of a character is its primitive condition

Synaphomorphic/ Apomorphic Trait

its later (descendant) state after transformation is its derived condition

Taxon

named group of organisms

sister group

taxon most closely related to the group we are studying

Phylogenetic systematics/ cladistics

method for determining relationships of organisms based on evolutionary history

Cladogram

dendrogram depicting genealogical relationships

Grade

an expression of the degree of change or level of adaptation reached by an evolving group

Clade

lineage, which is all organisms in a lineage plus the ancestor they have in common

ingroup

assortment of species (taxa) of interest in examining

Outgroup

close relative to but not party of this assortment

Monophyletic group

taxon that includes all common ancestors and descendant species

Paraphyletic group

taxon that includes the common ancestor and some of the descendants

Polyphyletic group

taxon that is formed on the basis of nonhomologous characters

Binomial

two-part scientific name of a species

Genus

the first part of the name

Hierarchical Classification

Domain, Kingdom, Phylum, Class, Order, Family, genus, Species