Significance in animal evolution: 1. There is a calcareous hard shell or leathery membrane with holes outside the egg, which plays a role in protection and gas exchange.

2The yolk end provides nutrition to the embryo

3. There are three membranes (amniotic membrane, chorion, and urinary membrane) and three cavities (amniotic cavity, extraembryonic cavity, and allantoic cavity). The amniotic cavity contains amniotic fluid to prevent embryo dryness and mechanical damage. The allantoic is a respiratory and excretory organ.

4. Meaning

Including egg membrane, egg shell, yolk, and embryo. Membrane structures such as amniotic membrane, chorion, and allantoic membrane constitute eggs, allowing amniotic animals to acquire fertility on land.

multilayered epidermis

Genuine Leather

skin glands

skull

spine, ribs, sternum

Secondary palate: Divides the oral pharynx into upper and lower layers, with the lower chamber for swallowing food and the upper chamber for respiratory passage to resolve the conflict between feeding and respiration.

oral glands

teeth

Cecum: The cecum has been produced since reptiles and is related to the digestion of plant fibers.

Incomplete separation of the ventricles (ventricular septum), incomplete double circulation, three-chamber heart

Metanephros appear, nephrons (such as glomeruli) increase, and have strong urinary capacity. The metanephros is the latest to appear in individual development. After the beginning of crawling, the kidneys urinate, and the excretion is mainly hydrochloric acid.

Mesonephric duct: used for insemination in males and involution in females

salt glands

Nervous system: Pyramidal cells make up nerve cells, and nerve cells make up the neocortex, the first appearance of reptiles. Most reptiles have 12 pairs of cranial nerves, but snakes and lizards have 11 pairs

Hearing organ: mainly composed of inner ear and middle ear

Infrared receptors: special receptors of reptiles, such as cheek fossae and lip fossae

The tuatara (wedge-toothed lizard) is called a living fossil

The raised pharyngeal wall and accessory bladders on both sides of the cloaca can serve as auxiliary organs during diving.

The vomeronasal organ does not open into the mouth

Refugee Branch, Refugee, also known as Chameleon

The upper and lower eyelids are specialized into transparent films that protect the eyeballs. They gradually become opaque and renew as the skin sheds.

Feel the vibrations from the ground through the square bones of your head

The highest reptile