Evolution and Characteristics of Amniotes

These flashcards cover terms and definitions related to the evolution and characteristics of amniotes, including their anatomical features and significant groups.

Synapsida

A group of animals including mammals and mammal-like reptiles characterized by having a single temporal fenestra.

Diapsida

A classification of reptiles characterized by having two temporal fenestrae in the skull.

Amniotic egg

An egg that contains extraembryonic membranes, allowing for the development of embryos in a terrestrial environment.

Fenestration

The presence of openings or windows in the skull that allow for increased muscle attachment and mass.

Therapsids

A more derived group of synapsids that includes mammals and their ancestors, characterized by increased metabolic rates.

Cynodonts

A subgroup of therapsids that are more closely related to mammals, known for features like differentiated teeth and reduced size.

Nasal turbinates

Scroll-like bones in the nasal passages that help reduce water and heat loss in mammals.

Tetrapoda

A superclass that includes all vertebrates with four limbs, including amphibians, reptiles, birds, and mammals.

Costal rib ventilation

A respiratory mechanism that involves ribs aiding in lung expansion, allowing for greater respiratory efficiency.

Chorion

The outermost membrane surrounding the embryo in an amniotic egg, playing a role in gas exchange.

Allantois

An extraembryonic membrane involved in waste storage and gas exchange, growing from the base of the embryo.

Sarcopterygii

A class of fish known as lobe-finned fish, which gave rise to terrestrial vertebrates.

Heterodont dentition

The condition of having different types of teeth (incisors, canines, molars) that serve various functions.

Pelycosaurs

Early synapsids, often confused with dinosaurs, known for their varied diets and body structures like sailbacks.