What is meant by plesiomorphy?
In phylogenetics, a plesiomorphy (“near form”) and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades.
What is an example of a plesiomorphy?
For example, primates form a more recently evolved mammalian group. Therefore, hair is a plesiomorphy (ancestral character) for primates. Because hair, as an ancestral mammalian character, is shared by all primates, it is also a symplesiomorphy (shared plesiomorphy) for primates in general.
What is apomorphy and plesiomorphy?
The term apomorphy means a specialized or derived character state; plesiomorphy refers to a primitive or ancestral trait. An same as autapomorphy is a derived trait that is unique to one group, while a same as synapomorphy is a derived trait shared by two or more groups.
What trait is plesiomorphy?
plesiomorphy (ancestral trait) An evolutionary trait that is homologous within a particular group of organisms but is not unique to members of that group (compare apomorphy) and therefore cannot be used as a diagnostic or defining character for the group.
Is a plesiomorphy a homology?
N&C’s (p. 162) argument that plesiomorphy is homology based on “occurrence of the same condition in the most recent common ancestor” is identical in its reasoning to the evolutionary taxonomists argument that paraphyly is monophyly.
What is plesiomorphy in taxonomy?
Plesiomorphy definition An evolved character or trait that is shared by some or all members of a phylogenetic group and their common ancestor but is not unique to that group.
How does plesiomorphy differ from apomorphy?
The main difference between apomorphy and plesiomorphy is that apomorphy refers to any character unique to a particular clade and its descendants whereas plesiomorphy refers to any character homologous within the clade but, not unique to all members. Snakes are a suborder of reptiles.
Are eggs a synapomorphy?
Eggs with amniotic fluid evolved in the common ancestor of all amniotes, and is a synapomorphy for Amniota; Etc.
Can a plesiomorphy be a synapomorphy?
Synapomorphy vs Plesiomorphy In the image above, the plesiomorphy identifies a character shared by two groups. Because the character (grayness) is not present in the darker organisms (black circles), the trait cannot be considered a synapomorphy.
What are synapomorphic characters?
Synapomorphies are characters shared by a group of taxa due to inheritance from a common ancestor. Thus, their depiction on a cladogram may facilitate the understanding of evolutionary relationships.