The Missing Link NOVA (2001)

Fins to limbs…The evidence lies in the Red Hill Sandstone.

1) What is a Tetrapod? What are typical examples of tetrapods?

What is an example of something that is not a tetrapod?

2) What is the difference between Rayfin fish and Lobefin fish?

When did Lobefin fish become common? What does that imply about the timing of the “terapod split?”

3) What is “Icthyostega?” This form has traditionally been assumed to be the “missing link,” but what why do they imply that this is NOT the case?

Did Icthyostega walk on land?

4) What is the Drying pond scenario? Who forwarded this idea?

What is the evidence that things were hot and dry in the Devonian?

5) What is a Coelacanth (“sea-le-canth”), and why is it amazing that these things are still alive?

6) The Acanthostega fossils from Greenland. How many finger? Could it walk? What is the implication of this find?

7) What is “Hinererperon?”

In this “Swamps first” idea, why did organisms need limbs?

In this discussion, what role did swamps play in this important evolutionary change?