Amniote Origin and Non avian Reptiles

Amniotes

vertebrates that lay eggs on land or retain them within the mother, characterized by the presence of an amniotic membrane.

Mesozoic

Have 3 stages called Triassic, Jurassic, and Cretaceous. The animals that were dominate were dinosaurs and marine reptiles.

Triassic

The first period of the Mesozoic Era, characterized by the emergence of dinosaurs, mammals, and the diversification of reptiles.

Jurassic

The second period of the Mesozoic Era, known for the dominance of large dinosaurs and the first appearance of birds and flowering plants.

Cretaceous

The final period of the Mesozoic Era, marked by the rise of flowering plants and the dominance of dinosaurs, leading up to their extinction.

Temporal Fenestrae

An anatomical feature found in the skulls of amniotes, including reptiles and mammals, which are openings that allow for greater flexibility and muscle attachment.

Anapsid

No openings in their skulls

Diapsid

Amniotes with two temporal fenestrae in their skulls, which allows for stronger jaw muscles and has led to a diverse group including lizards and birds.

Synapsid

Amniotes with a single temporal fenestra in their skulls, characterized by an evolutionary trend towards larger brains and differentiated teeth, including mammals.

Amniotic Egg

An evolutionary innovation in which the embryo develops within a fluid-filled sac, providing protection and nourishment, critical for the reproductive success of amniotes.

Reduced the need for water

Waterproof Skin

Helps prevent water loss.

Negative Pressure Breathing

A respiratory mechanism used by amniotes where the expansion of the thoracic cavity creates a vacuum that pulls air into the lungs, enhancing respiratory efficiency.

Key features are the use of diaphragm and intercostal muscles to facilitate inhalation and exhalation.

Strong Jaws

Adaptations in many non-avian reptiles enabling them to effectively capture and process prey, featuring muscularity and specialized teeth for biting and grinding.

Extraembryonic Membranes

Structures that support the developing embryo, including the amnion, chorion, allantois, and yolk sac, playing crucial roles in gas exchange, nutrient transfer, and waste management.

Amnion

Protects from mechanical shock and helps maintain a stable environment for the embryo.

Allantois

A membrane involved in waste management.

Chorion

The outermost membrane that surrounds the embryo and facilitates gas exchange between the embryo and the environment.

Yolk

The nutrient-rich substance that provides food for the developing embryo.

Scale

A protective outer covering found on the skin of many reptiles and some other animals, typically composed of keratin.

Rises from the epidermis.

Internal Fertilization

The process where sperm fertilizes an egg inside the reproductive tract of the female, ensuring protection for the developing embryo.

Inside the female.

Keratin

A fibrous protein that is a key structural component of scales, feathers, hooves, and hair in various animals, providing toughness and resilience.

Beta Keratin

a type of keratin found in scales, feathers, and certain other structures in reptiles and birds, providing strength and rigidity.