Mollusca and Tethys Ocean - Lecture 5

Question 1

Name three classes of mollusca

Answer 1

Gastropoda, Bivalvia and Cephalopoda

Question 2

What is the most developed kind of mollusca?

Answer 2

Cephalopods as they have the most sensory organs

Question 3

What four features can be used to recognise a mollusc?

Answer 3

Has growth lines, soft inner body, shell has three layers, shell made of calcite/aragonite or both

Question 4

Define homeomorphy

Answer 4

the evolution of similar external forms from very distant ancestors. e.g. rudist bivalves show homeomorphy with rugose corals.

Question 5

Where did the Tethys Ocean open and when did this occur?

Answer 5

Equatorial region of Mesozoic and most of the Tertiary

Question 6

What limits coral reef growth

Answer 6

Sea depth, avaliability of light and the need for warm waters

Question 7

Explain the formation of an atoll

Answer 7

Atoll forms as volcano extends out of an ocean it gets eroded. Fringing reef forms. Further erosion and further build up of reef causes a barrier reef to form. Lagoon forms as volcano eroded below sea level and atoll is formed.

Question 8

What were the effects of the K-T boundary?

Answer 8

Decrease in species range. Benthic organisms unaffected dinosaurs disappeared and mammal faunas increased