Mollusca and Tethys Ocean - Lecture 5 Flashcards
Name three classes of mollusca
Gastropoda, Bivalvia and Cephalopoda
What is the most developed kind of mollusca?
Cephalopods as they have the most sensory organs
What four features can be used to recognise a mollusc?
Has growth lines, soft inner body, shell has three layers, shell made of calcite/aragonite or both
Define homeomorphy
the evolution of similar external forms from very distant ancestors. e.g. rudist bivalves show homeomorphy with rugose corals.
Where did the Tethys Ocean open and when did this occur?
Equatorial region of Mesozoic and most of the Tertiary
What limits coral reef growth
Sea depth, avaliability of light and the need for warm waters
Explain the formation of an atoll
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.
What were the effects of the K-T boundary?
Decrease in species range. Benthic organisms unaffected dinosaurs disappeared and mammal faunas increased
