Paleozoic Brachiopod Fossils and Trochozoans in BIOL 108 Winter 2024

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Questions and Answers

What is the main mode of feeding in brachiopods?

Omnivorous feeding

Carnivorous feeding

Suspension feeding (correct)

Deposit feeding

During which geological era were brachiopods highly diverse?

Mesozoic era

Paleozoic era (correct)

Cenozoic era

Jurassic era

What is the characteristic of the gut of brachiopods?

Complete with the anal opening inside the lophophore

Incomplete with the anal opening at the base of the lophophore

U-shaped with the anal opening outside of the lophophore

Complete with the anal opening outside of the lophophore (correct)

How many extant species of brachiopods are there?

Around 300 species Signup and view all the answers

What is the meaning of the prefix 'brach' in the word brachiopod?

Arm Signup and view all the answers

What is the primary way brachiopods attach to the seafloor?

Using a stalk Signup and view all the answers

What distinguishes trochozoans in terms of early embryonic development?

Presence of microscopic motile trochophore larvae Signup and view all the answers

Which statement best describes trochophores?

Planktonic larvae characterized by two bands of cilia Signup and view all the answers

What is the main characteristic shared by all molluscs?

Soft-bodied animals with calcium carbonate shells Signup and view all the answers

Why is the name 'Mollusca' related to the soft bodies of octopuses and cuttlefish?

Referring to the soft nature of their bodies Signup and view all the answers

How do molluscs protect themselves?

With a hard calcareous shell Signup and view all the answers

What is a key characteristic of Phylum Mollusca?

Diverse group including land snails and octopuses Signup and view all the answers

What is the primary function of the radula in chitons?

To scrape algae off surfaces Signup and view all the answers

Approximately how many species of gastropods exist?

70,000 Signup and view all the answers

What is the main function of the shell in gastropods?

To protect from injury, dehydration, and predation Signup and view all the answers

What is characteristic of terrestrial gastropods?

They have direct development of juveniles without a trochophore larval stage Signup and view all the answers

How do terrestrial snails and slugs move?

Using muscular motions of the ventral foot Signup and view all the answers

What is the function of the mantle cavity in terrestrial snails and slugs?

It evolved into a simple lung Signup and view all the answers

What is the primary mode of reproduction in ectoprocts?

Both sexual and asexual reproduction Signup and view all the answers

What is the composition of the exoskeletons of freshwater ectoprocts?

Gelatinous or chitinous Signup and view all the answers

What is the function of the lophophore in ectoprocts?

To suspension feed Signup and view all the answers

How do ectoprocts attach to the substrate?

They do not attach to the substrate Signup and view all the answers

What is the shape of the gut in ectoprocts?

U-shaped Signup and view all the answers

How many extant species of ectoprocts are there?

Approximately 4,500 Signup and view all the answers

What is a characteristic of the body plan of flatworms?

triploblastic development but lack of fluid-filled body cavities Signup and view all the answers

How do flatworms exchange gases?

across the body surface, aided by a dorsoventrally flattened shape Signup and view all the answers

What is the name of the low diversity group of flatworms that are primarily found in freshwater habitats and reproduce asexually by budding?

Catenulida Signup and view all the answers

What is the approximate number of species of flatworms in the lineage Rhabditophora?

20,000 species Signup and view all the answers

What is the characteristic of the digestive tract of flatworms?

incomplete digestive tract with mouth and gut cavity Signup and view all the answers

What is the habitat of planarians?

freshwater and terrestrial environments Signup and view all the answers

What is a key characteristic of Acoela species?

Absence of a brain Signup and view all the answers

Which digestive system characteristic is unique to Acoela species?

Endocellular digestion Signup and view all the answers

What distinguishes Lophotrochozoa from other clades?

Well-defined unifying characteristic Signup and view all the answers

Which larval development process is associated with some lophotrochozoans?

Trochophore stage Signup and view all the answers

What is a common trait of Acoela and Lophotrochozoa?

No brain structure Signup and view all the answers

How are Acoela species classified based on their feeding habits?

Predators or scavengers Signup and view all the answers

What is the primary function of the radula in molluscs?

To scrape or cut food Signup and view all the answers

What is the characteristic of the body plan of molluscs?

Unsegmented Signup and view all the answers

What is the location of the gills in molluscs?

In the mantle cavity Signup and view all the answers

What is the function of the mantle in molluscs?

To secrete the shell Signup and view all the answers

What is the characteristic of the phylum Mollusca that includes a wide range of species?

Having a diverse range of over 100,000 extant species Signup and view all the answers

What is the characteristic of the circulatory system in most molluscs?

Open circulatory system Signup and view all the answers

What is the characteristic of the life cycle of many molluscs?

It includes a ciliated trochophore larval stage Signup and view all the answers

What is the primary function of the shell in molluscs?

Protection from predators Signup and view all the answers

What is the common characteristic of trochozoans in terms of embryonic development?

Sharing patterns of early embryonic development Signup and view all the answers

Which of the following is a characteristic of molluscs?

Having a soft body Signup and view all the answers

What is the name of the larval stage that is characteristic of trochozoans?

Trochophore Signup and view all the answers

What is the primary habitat of molluscs?

Both marine and freshwater, with some species being terrestrial Signup and view all the answers

What is the main function of the tentacles in cephalopods?

Feeding, grasping, and movement Signup and view all the answers

What distinguishes cephalopods from other molluscs in terms of circulation?

Close circulatory system Signup and view all the answers

Which structure do squids and some octopuses use for fast swimming?

Siphon Signup and view all the answers

What is the primary mode of locomotion for most octopuses?

Jet propulsion Signup and view all the answers

How many species of chambered nautiluses are estimated to exist?

Approximately 900 Signup and view all the answers

What is the advantage of having a closed circulatory system for cephalopods?

Supporting a very active lifestyle Signup and view all the answers

Study Notes

Brachiopods Feeding and Habitat

Main mode of feeding in brachiopods is through suspension feeding, using lophophores to capture particles.
Brachiopods were highly diverse during the Paleozoic era.
Brachiopods possess a simple gut that is often U-shaped.
There are approximately 300 extant species of brachiopods.
The prefix 'brach' in brachiopod means "arm," referring to the structure of the lophophore.

Attachment and Development in Trochozoans

Brachiopods primarily attach to the seafloor using a pedicle.
Trochozoans can be distinguished by having a specific pattern of early embryonic development.
Trochophores are free-swimming larval stages with ciliated bands.

Molluscs Characteristics and Behavior

Main characteristic shared by all molluscs is a soft body, often protected by a shell.
The name 'Mollusca' is derived from Latin, meaning "soft," relating to their body structure such as in octopuses and cuttlefish.
Molluscs protect themselves with shells made of calcium carbonate.
Key characteristic of Phylum Mollusca includes a coelom and a complete digestive system.
The radula in chitons primarily functions in scraping food from surfaces.

Gastropods and Movement

Approximately 80,000 species of gastropods exist.
The main function of the shell in gastropods is to provide protection and prevent desiccation.
Terrestrial gastropods are characterized by their ability to survive in land habitats.
Terrestrial snails and slugs move using a muscular foot that glides on a layer of mucus.
The mantle cavity in terrestrial snails and slugs functions in respiration and housing the gills.

Ectoprocts Structure and Attachment

Primary mode of reproduction in ectoprocts is asexual budding.
The exoskeletons of freshwater ectoprocts are composed of chitin.
The lophophore in ectoprocts functions in feeding and gas exchange.
Ectoprocts attach to substrates with a structure called a stolon.
Ectoprocts have a U-shaped gut.

Flatworms and Their Habitats

Flatworms are characterized by their flattened body plan.
Gas exchange in flatworms occurs directly across their skin.
A low diversity group of flatworms found in freshwater habitats that reproduce asexually by budding is called "Planarians."
Approximately 20,000 species of flatworms exist in the lineage Rhabditophora.
Flatworms possess an incomplete digestive tract with a single opening.

Acoela and Lophotrochozoa Traits

Planarians primarily inhabit freshwater environments.
Acoela species are unique in their simple body structure and lack of a true gut.
Lophotrochozoa can be distinguished by the presence of trochozoan-like larval stages in some members.
Acoela species can be classified based on their varied feeding habits: some are detritivores, others are carnivorous.

Molluscs Structure and Life Cycle

The primary function of the radula in molluscs varies, mainly used for feeding and rasping.
Molluscs exhibit a diverse body plan, often divided into three main parts: foot, visceral mass, and mantle.
Gills in molluscs are typically located within the mantle cavity.
The mantle in molluscs secretes the shell and aids in respiration.
The wide range of species in Phylum Mollusca showcases their adaptability to various environments.

Circulatory and Developmental Details

Most molluscs have an open circulatory system but cephalopods possess a closed circulatory system, allowing for better oxygen transport.
Many molluscs have complex life cycles that involve both larval and adult stages.
The primary function of the shell in molluscs is protection against predators and environmental hazards.
Trochozoans display a common embryonic development pattern characterized by the trochophore larval stage.
The primary habitat of molluscs includes marine, freshwater, and terrestrial environments.

Cephalopods Characteristics

The main function of tentacles in cephalopods is for capturing prey and maneuvering.
Cephalopods are distinguished from other molluscs by their closed circulatory system, allowing for efficient movement and active predation.
Squids and some octopuses utilize jet propulsion through a siphon for rapid swimming.
The primary mode of locomotion for most octopuses is crawling using their arms.
Chambered nautiluses are estimated to have around 6 extant species.
A closed circulatory system in cephalopods provides advantages such as increased efficiency in oxygen delivery during high activity levels.

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Description

Learn about Paleozoic brachiopod fossils and the classification of Trochozoans in the context of BIOL 108 Winter 2024 course. Explore the relationship between Trochozoa, phylum Annelida, and phylum Mollusca, focusing on their early embryonic development and distinctive characteristics.