Week 5 - Shell Morphology Flashcards
What is the goal of using shell morphology in paleontology?
To infer mode of life, environment of deposition, and extinction/recovery patterns.
What is the main difference between articulate and inarticulate brachiopods?
Articulates have hinge teeth, while inarticulates lack them.
What is Lingula, and why is it significant?
A living inarticulate brachiopod that has remained unchanged since the Cambrian.
How do brachiopods feed?
They use a lophophore, a filter-feeding structure.
Why have brachiopods declined in diversity compared to bivalves?
Bivalves outcompeted them in many ecological niches.
What are gastropods?
Molluscs with coiled shells, including snails and limpets.
What are the two main types of shell coiling in gastropods?
Dextral (right-handed) and sinistral (left-handed).
What material do gastropods use for their shells?
Aragonite, which is less well-preserved than calcite.
What is Crysomallon squamiferum, and what is unique about its shell?
A deep-sea hydrothermal vent gastropod with pyrite (iron sulfide) in its shell.
What distinguishes bivalves from brachiopods?
Bivalves have symmetry between the two valves, while brachiopods have symmetry within each valve.
What is the function of the pallial sinus in bivalves?
It indicates the presence of siphons for burrowing.
How does shell thickness relate to environment?
Thicker, ribbed shells are adapted for high-energy environments.
What feeding strategies do bivalves use?
Suspension feeding, deposit feeding, predation, and mining.
When did the K-Pg extinction occur, and what caused it?
66 million years ago, likely due to an asteroid impact.
How did bivalves respond to the K-Pg extinction?
There was a shift towards smaller, deeper-burrowing species.
What factors influenced bivalve survival after the K-Pg event?
Predation pressure and climate change affected recovery pattern
What is the significance of veneroid bivalves in K-Pg recovery studies?
They were abundant and well-preserved, providing a detailed extinction/recovery record.
