Tetrapods 2

Question 1

When and from what did tetrapods initially evolve?

Answer 1

Tetrapods evolved from Sarcoptergian (lobe finned fishes) in Devonian and first vertebrates to colonise land.

Question 2

Describe the sense organs of tetrapods.

Answer 2

• Middle ear of tetrapods

* Vision - easier in air so flatter lens than fish. Eyes on top of head.

Question 3

When did terrestrial tetrapods arise?

Answer 3

Carboniferous period.

Question 4

What are the three major events of tetrapod evolution?

Answer 4

• Origin of limbs with digits
• Origin of walking
• Origin of terrestriality.

Question 5

What problems did aquatic vertebrates have to overcome before they could survive on land?

Answer 5

• Withstand effects of gravity
• Breathe air
• Minimise water loss (desiccation)
• Adjust senses for use in air.

Question 6

What are the adaptions seen in tetrapods for breathing above water?

Answer 6

• Elongate snout, fewer bones and stronger sutures
• String bones at back of head for muscle attachment
• Fusing bones of lower jaw for buccal pump - mouth cavity bellows-like action gulping air forces into lungs.