TETRAPODS

Question 1

Tetrapoda are found in which superclass?

Answer 1

gnathostomata

Question 2

Summary of differences between living on land than in water

Answer 2

• air is way less dense, in water species must focus on maintaining buoyancy whereas on land they must develop elaborate support structures

Question 3

How does body temperature regulation vary between land and sea?

Answer 3

• land it is easy to regulate temperature different to surroundings but there is great variation
• water there is very little variation but hard to maintain different temperature to surroundings

Question 4

How does sensory perception vary between land and sea?

Answer 4

in water, light is scattered and refracted and is a good electroconductor

on land, light is less disturbed and small molecules transmit well

Question 5

Who are 4 close relatives of Tetrapoda?

Answer 5

• ray finned fish (fins have spines)
• lobe finned fish (bores in fin)
• lung fish
• coelocanths

Question 6

The gap between fish and tetrapods required changes in what characteristics.

_____ (388 mya)

Answer 6

• dorsoventrally flattened
• longer ribs
• stronger limb girdles
• loss of dorsal fins

PANDERICHTYS

Question 7

What was the ‘first tetrapod’? What kind of structures did it have?

Answer 7

ACANTHOSTEGA

• flubber limbs
• developed fingers and toes
• pelvis
• tetrapod like neck and vertebrae
• fish tail
• short ribs
• internal gills

Question 8

3 key structural changes

Answer 8

1) limbs

2) skulls, opercular gill cover bones are reduced and become the neck
- posterior of skull becomes shorterned and anterior lengthened
- skull solidified and becomes less flexible
- flattening of head

3) skeleton becomes visible

Question 9

Potential reasons for moving to land

Answer 9

1) escaping predators
- Acanthostega is thought

2) seasonal droughts, but not really applicable to marine habitats
3) more food
4) to elevate temp in sun