TED-Ed: How turtle shells evolved... twice - Judy Cebra Thomas

The video explores the evolution and development of turtle shells, starting with Odontochelys, an early turtle ancestor. It explains how turtle embryos develop two separate shells, the carapace and plastron, through unique cellular processes. The video also discusses the evolutionary history of turtle shells, highlighting key ancestors like Eunotosaurus and Proganochelys. Finally, it examines the diversity of modern turtle shells, adapted for different environments, such as sea turtles and tortoises.

What is the primary function of the carapacial ridge in turtle embryos?

• To create the turtle's neural crest cells

• To develop the turtle's digestive system

• To guide the formation of the carapace

• To form the turtle's limbs

How do turtles manage to breathe given their rigid shell structure?

• By using abdominal muscles attached to the shell

• By absorbing oxygen through their skin

• By inflating their carapace

• By expanding their rib cage

Which ancient turtle ancestor had broad, flat ribs and was likely a burrowing creature?

• Chelonia mydas

• Proganochelys quenstedti

• Odontochelys semitestacea

• Eunotosaurus africanus

What is a unique feature of sea turtle shells compared to land-dwelling tortoises?

• Sea turtles have retractable heads

• Sea turtles have domed shells

• Sea turtles have flatter, lighter shells

• Sea turtles have spines on their necks

Why do leatherback and softshell turtles have shells without the ring of bone around the edge?

• To enhance their swimming speed

• To allow them to squeeze into tight spaces

• To protect them from predators

• To support their heavy weight