Brachiopods Classification Flashcards

Questions and Answers

How are brachiopods traditionally classified?

Phylum Mollusca

Phylum Brachiopoda (correct)

Phylum Cnidaria

Phylum Arthropoda

The traditional classification of Brachiopods is still in use today.

False

List the levels in the Linnean classification system.

Kingdom, Phylum, Class, Order, Family, Genus, Species

What are phylogenetic differences?

Differences in a species' physical or genetic characteristics. Signup and view all the answers

What are the two classes in the traditional classification system of Brachiopods?

Class Articulata and Class Inarticulata Signup and view all the answers

When did the Class Articulata and Class Inarticulata exist?

Late Cambrian to recent Signup and view all the answers

What makes a good guide fossil?

Free moving, widespread, rapidly evolving, abundant, readily preserved, cross-environment and easily recognized. Signup and view all the answers

What are bilaterians?

Animals with bilateral symmetry. Signup and view all the answers

What are radiata?

Jellyfish and other radially symmetric animals. Signup and view all the answers

How are Brachiopods currently classified?

Phylum Brachiopoda; Sub-phylum Linguliforms, Sub-phylum Craniforms, Sub-phylum Rhynchonelliforms. Signup and view all the answers

When did the Orthida exist?

Cambrian to Permian. Signup and view all the answers

When did the Pentamerida exist?

Cambrian to Devonian. Signup and view all the answers

When did the Order Productida exist?

Ordovician to Permian. Signup and view all the answers

When did the Order Rhynchonellida exist?

Ordovician to Recent. Signup and view all the answers

When did the Order Spiriferida exist?

Ordovician to Triassic. Signup and view all the answers

When did Order Strophomenida exist?

Ordovician to Carboniferous. Signup and view all the answers

When did Order Terebratulida exist?

Devonian to Recent. Signup and view all the answers

What shell geometry do brachiopods exhibit?

Inequivalve but equilateral. Signup and view all the answers

How do you tell the difference between bivalves and brachiopods?

Bivalves are usually symmetrical between valves but not across valves. Brachiopod valves are symmetrical as individual valves but different from each other. Signup and view all the answers

What are the main components of a brachiopod's shell?

Dorsal and Ventral, Hole for pedicle, Sulcus, Ribs and Commissure, Two valves (shells), Beak. Signup and view all the answers

What are brachiopod shells made of? Why is this significant?

Low magnesian calcite, which makes it readily preservable due to its erosion resistance. Signup and view all the answers

What does the commissure represent on a brachiopod's shell?

Growth lines. Signup and view all the answers

Which is the Dorsal surface on a Brachiopod?

The side which does not have the pedicle attachment. Signup and view all the answers

Which is the Ventral surface on a brachiopod?

The surface with the pedicle attachment or overhanging surface. Signup and view all the answers

What is the unique purpose of muscles in a brachiopod?

There are 2 different sets - one to open the brachiopod and one to close. Signup and view all the answers

What is the purpose of the sulcus?

For filter feeding; the fold where the water leaves after a brachiopod has fed. Signup and view all the answers

What is the purpose of the pedicle?

Attaches pedicle to prevent being swept away by current. Signup and view all the answers

What is the purpose of the ribs on a brachiopod's shell?

Gives the shell more strength. Signup and view all the answers

What are two reasons why a brachiopod might have a thick shell?

To provide stability and prevent flipping over, or for defense from predators. Signup and view all the answers

The brachiopod's shell structure consists of three types: ______.

To be determined Signup and view all the answers

Study Notes

Classification of Brachiopods

Traditional classification includes Phylum Brachiopoda with two main classes: Articulata and Inarticulata.
Articulata includes various orders such as Orthida, Pentamerida, Productida, Rhynchonellida, Spiriferida, Strophomenida, and Terebratulida, spanning from the Cambrian to Recent.
Inarticulata includes the order Lingulida, found from Cambrian to Recent.
The traditional classification is often criticized due to lack of phylogenetic differences between the two classes.

Linnean Classification System

Hierarchical classification levels: Kingdom, Phylum, Class, Order, Family, Genus, Species.

Phylogenetic Differences

Refers to the variations in the physical or genetic characteristics of species, important for understanding evolutionary relationships.

Current Classification of Brachiopods

Recent classification breaks down into three sub-phylums: Linguliforms, Craniforms, and Rhynchonelliforms.
Current orders still include those from Articulata based on evolutionary relevance.

Guide Fossils

Characteristics of good guide fossils: free-moving, widespread, rapidly evolving, abundant, readily preserved, and easily identifiable.
Two most crucial traits: rapid evolution and ease of preservation.

Brachiopod Symmetry and Shell Structure

Brachiopods are bilaterally symmetrical with inequivalve but equilateral shells, showing distinct left and right shells.
Distinction from bivalves: bivalves have symmetrical valves, while brachiopod valves differ individually.

Shell Composition and Features

Brachiopod shells are made of low magnesian calcite, important for preservation due to resistance to erosion.
Key components of shell: dorsal and ventral valves, pedicle hole, sulcus, ribs, commissure, and beak.

Musculature and Functionality

Two muscle sets in brachiopods: one for opening and one for closing the shell.
Sulcus aids in filter feeding by allowing water exit after feeding.

Pedicle and Shell Reinforcement

The pedicle attaches brachiopods to surfaces, preventing displacement by currents.
Ribs enhance shell strength, contributing to stability and defense against predators.

Shell Thickness

Thick shells in brachiopods provide stability, prevent flipping, and offer defense mechanisms against predation.

Unique Brachiopod Characteristics

Brachiopods possess distinct shell features such as growth lines represented by the commissure, and differentiated dorsal and ventral surfaces based on pedicle attachment.

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Description

Explore the traditional classification of brachiopods through these flashcards. Learn about the different classes and orders within Phylum Brachiopoda. This quiz will help solidify your understanding of brachiopod taxonomy and its traditional usage.