What characterizes an amniote?
Key Points. The amniotes include reptiles, birds, and mammals; shared characteristics between this group include a shelled egg protected by amniotic membranes, waterproof skin, and rib ventilation of the lungs.
What do all amniotes have in common?
All amniotes have three membranes surrounding the fetus of one offspring. These membranes are the amnion, or protective layer, the top chorion layer, and the waste-absorbing allantois. These layers can be seen in the image of a chicken egg, below.
What are some of the properties of an amniote egg?
Characteristics of Amniotes The amniotic egg is the key characteristic of amniotes. In amniotes that lay eggs, the shell of the egg provides protection for the developing embryo while being permeable enough to allow for the exchange of carbon dioxide and oxygen.
Which is not an amniote?
Answer and Explanation: The animal that is NOT an amniote is A) bullfrog. Amniotes are vertebrates that are within an amnion during embryonic or fetal development.
Are eggs a Synapomorphy?
Eggs with amniotic fluid evolved in the common ancestor of all amniotes, and is a synapomorphy for Amniota; Etc.
What are the parts of the Amniote egg?
The structure of the amniote egg. Inside the egg are a series of fluid-filled membranes which permit the embryo to survive: the amnion, allantois, yolk sac, and chorion. Surrounding and protecting the embryo is the amnion, filled with amniotic fluid, and providing the embryo with a stable fluid environment.
What is a defining characteristic of members of the class testudines?
What is a defining characteristic of members of the Class Testudines? They have a hard shell.
What are the parts of the amniote egg?
What was the adaptive significance of the amniote egg?
What was the adaptive significance of the amniote egg? It allows reproduction on land.
What is a defining characteristic of members of the class Testudines quizlet?
Why are turtles called Testudines?
The order has also been historically known as Chelonii (Latreille 1800) and Chelonia (Ross and Macartney 1802), which are based on the Ancient Greek word for tortoise: χελώνη (chelone). Testudines is the official order name due to the principle of priority.
What is synapomorphy definition?
Definition of synapomorphy : a character or trait that is shared by two or more taxonomic groups and is derived through evolution from a common ancestral form.
What is a synapomorphy example?
For example, the presence of mammary glands is a synapomorphy for mammals in relation to tetrapods but is a symplesiomorphy for mammals in relation to one another—rodents and primates, for example.
Which fish were thought to be extinct but were actually found in living populations?
Coelacanths were thought to have become extinct in the Late Cretaceous, around 66 million years ago, but were discovered living off the coast of South Africa in 1938.
What is the definition for Testudines?
An order of reptiles which comprises the turtles, terrapins, and tortoises.
How many Testudines are there?
The testudines are some of the most ancient reptiles alive, with only the tuataras considered more primitive. There are approximately 300 extant species and 97 genera of testudines, split into two suborders: the Cryptodirans and the Pleurodirans.
Did fish exist with dinosaurs?
Since the extinction event that wiped out the dinosaurs 66 million years ago, fish have evolved and diversified, leading to the wide variety of fish species we see today.
What means frangible?
readily or easily broken
Definition of frangible : readily or easily broken.
What are amniotes?
Amniotes are tetrapods (descendants of four-limbed and backboned animals) that are characterised by having an egg equipped with an amnion, an adaptation to lay eggs on land rather than in water as the anamniotes (including frogs) typically do.
What is a synapomorphy?
In fact, the term synapomorphy comes from the Greek “syn” meaning shared, “apo” meaning away from, and “morphe” meaning form or shape. In other words, the animals have a shared form as they move away from their ancestors and related animals. A synapomorphy can help scientists determine which groups of animals are related, and which aren’t.
Are seymouriamorphs amniotes?
The seymouriamorphs are an early divergent group of anthracosaurs, although their fossil history does not begin until the Late Pennsylvanian. These small tetrapods probably had external development and required water for reproduction. Neither seymouriamorphs nor diadectomorphs are amniotes ( Fig. 1.12 ).
What are the sauropsid amniotes and synapsids?
The sauropsid amniotes include the reptiles and birds. Formally, this constitutes many different groups, but the sauropsid amniotes share many derived characteristics which separate them from the synapsids. The two groups evolved around the same time, from a common ancestor which was likely not terrestrial.