Porifera: Sponges and Their Structures

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Questions and Answers

What characteristic distinguishes Demoisponge spicules from those of Calcarea?

Demoisponge spicules are made of silica.

Demoisponge spicules contain spongin. (correct)

Demoisponge spicules are primarily made from calcium carbonate.

Demoisponge spicules are primarily found in deep water.

Which of the following correctly describes the reproductive strategy of Demospongiae in seasonal environments?

They die in spring but leave live offspring.

They only reproduce asexually.

They leave behind gemmules during the winter. (correct)

They reproduce continuously throughout the year.

What is a significant structural feature of Homoscleromorpha sponges?

They have a large number of spicules.

They possess complex pinacoderms.

Their pinacoderm includes a basal lamina. (correct)

They have a well-developed mesophyll layer.

How do sponges in the Demospongiae class adapt to their environments?

By using hook-like spicules to capture prey. Signup and view all the answers

Which form of sponge is characterized as the simplest of structures?

Asconoid Signup and view all the answers

What cell type in sponges is responsible for allowing water flow through the body wall?

Porocytes Signup and view all the answers

Which layer of sponge cells is primarily involved in capturing food?

Choanoderm Signup and view all the answers

What is the role of archaeocytes in sponges?

Differentiate into various cell types Signup and view all the answers

Which of the following statements about sponge reproduction is correct?

Sponge asexual reproduction can involve budding and fragmentation. Signup and view all the answers

Which statement accurately describes the spongocoel in sponges?

It lacks true spongocoel in most sponges. Signup and view all the answers

During sponge development, what type of cell migrates inwards to line the chambers?

Flagellated cells Signup and view all the answers

Where do sperm develop in sponges?

From choanocytes with flagella Signup and view all the answers

Which component is NOT part of the sponge cell structure?

Epithelial cells Signup and view all the answers

What is the function of spongocytes in sponges?

Secrete spongin Signup and view all the answers

Which of the following best describes the relationship between sponges and true tissues?

Sponges lack true tissues and distinct germ layers. Signup and view all the answers

What distinguishes Hexactinellida among sponges?

They are known for having siliceous spicules. Signup and view all the answers

Which of the following ecological relationships does not typically involve Hexactinellida?

Competing for nutrients directly from the water column. Signup and view all the answers

Which feature of Hexactinellida allows them to potentially live for thousands of years?

Their indeterminate growth. Signup and view all the answers

What is the primary composition of the skeleton of Hexactinellida?

Silica. Signup and view all the answers

What advantage do sponges provide in tissue engineering?

Their fibrous elements. Signup and view all the answers

What is a characteristic feature of Placozoa?

They lack defined symmetry. Signup and view all the answers

Which relationship does not benefit the Hexactinellida sponge?

Being preyed upon by marine turtles. Signup and view all the answers

Which characteristic is true about the ecological role of Hexactinellida?

They can host a variety of parasitic organisms. Signup and view all the answers

Study Notes

Porifera

Sponges belong to the Phylum Porifera
Sponges are multicellular and have specialized cells for different functions.
There are three main types of canal systems in sponges: asconoid, syconoid, and leuconoid.
Asconoid sponges have a simple structure with a single large spongocoel.
Syconoid sponges have folded body walls, increasing the surface area for choanocytes.
Leuconoid sponges are the most complex, with a network of flagellated chambers.
Sponges have three main cell layers: choanoderm (inner layer of choanocytes), pinacoderm (outer layer of pinacocytes), and mesohyl (gelatinous matrix).
Sponges do not have true tissues, but they have several other cell types besides the three main layers.
Other cell types in sponges include porocytes, archaeocytes, collencytes, sclerocytes, and spongocytes.
Sponges reproduce asexually through budding, fragmentation, and the formation of gemmules.
Gemmules are dormant masses of archaeocytes that can survive harsh conditions.
Sponges reproduce sexually through fertilization, either internally or externally.
Most sponges are hermaphroditic, producing both sperm and eggs.
Sponges develop from free-swimming, ciliated larvae.
There are four major clades of sponges: Homoscleromorpha, Calcarea, Demospongiae, and Hexactinellida.
Homoscleromorpha sponges are typically simple and may lack spicules.
Calcarea sponges have spicules made of calcium carbonate and can be asconoid, syconoid, or leuconoid.
Demospongiae sponges are the largest group and are mostly leuconoid with spicules made of silica and spongin.
Hexactinellida sponges are known as glass sponges due to their silica spicules and have a syncytial structure.
Sponges play important ecological roles, including being prey for predators, hosts for parasites and commensals, and competitors with other organisms.
Sponges have been used by humans for various purposes, such as medicinal properties, tissue engineering, fiber optic properties, and to remove chemical pollution.
Placozoa animals are very small and lack fixed shapes.
Placozoa animals are free-living and do not have true tissues.
Placozoa animals have 6 different cell types

Placozoa

One of the smallest animals
Free-living
No fixed shape or symmetry, flat bob shape
Have dorsal and ventral cilia
Sister taxon obscure, thought to possibly be related to sponges
Have 6 types of cells

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Description

Explore the fascinating world of sponges in this quiz on the Phylum Porifera. Learn about the different types of canal systems, specialized cells, and unique reproductive methods of these remarkable organisms. Test your knowledge on their cellular structure and classification.