Amniotes/ Amniotic Clade: mammals and reptiles

Question 1

What two phylums does amniotic clade include?

Answer 1

mammals and reptiles

Question 2

what species could reptiles be?

Answer 2

birds, turtles, lizards, crocodiles, dinosaurs, and others

Question 3

what is the main shift in amniotes?

Answer 3

have many adaptation for terrestrial life –> and key unifying feature is amniotic egg

Question 4

What are some features on the internal fertilization and amniotic egg development?

Answer 4

internal fertilization means that they don’t need to have water for sperm to be transferred

• amniotic egg: protects from desiccation (shell, corion and amnion)
• allows for gas exchange (allantois, and chorion)
• Nutrients (yolk)
• allantois forms placenta in mammals

Question 5

What are some other characteristics for terrestrial life in amniotic clade?

Answer 5

1. copulation and internal fertilization
2. waterproof skin –> less permeable and must rely on lungs for gas exchange
3. muscles associated with rib cage to ventilate lungs and are more efficient than buccal pumps

Question 6

What are the two major clades within the amniote phylogeny and what consists of each clade?

Answer 6

1. reptilia –> consists of birds

2. Synapsida –> consists of mammals and many extinct taxa

Question 7

What are some skull hole features in amniotic clade?

Answer 7

diapsids have two holes per side behind their eye sockets like reptiles
- synapse have one hole per side like mammals
and anapsid have no holes like turtles
- the number of major holes in the post-jaw area of skull is important to classify amniotes
- holes allow muscles to pass through the jaw to control jaw movement

Question 8

what are some characteristics of non-avian reptilia? what species does it include?

Answer 8

• includes turtles, crocodiles, lizards and snakes
• skin is protected by keratinous scales which prevent desiccation
• shed in sections (like turtles) OR all at once (like snakes and lizards) but do not shed the lining of their gut and respiratory passages
• they have a leathery eggshell that protects from drying out and a few species have viviparous birth