Questions and Answers
What is the Latin name of the phylum commonly known as sponges?
What are invertebrates?
Animals without a backbone.
What are sponges classified as?
Aquatic animals that make up the phylum Porifera.
What does 'sessile' mean in reference to sponges?
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The basic body structure of a sponge consists of two layers of cells separated by a jellylike substance called ______.
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What are chanocytes?
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What are the pores through which water enters a sponge called?
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What is the name of the opening through which water leaves the sponge?
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What are spongins?
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How do sponges primarily feed?
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How can sponges reproduce?
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Sponges can reproduce ______ by forming small buds that break off.
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Sponges reproduce ______ by releasing sperm into the water.
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Which two phyla are more complex than regular sponges?
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What shape is the medusa form of cnidarians?
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What shape is the polyp form of cnidarians?
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Name the two layers of cells that cnidarians are constructed with.
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What is the jellylike material between the layers of cnidarians called?
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What is the mouth of the cnidarians called?
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What are the flexible extensions surrounding the mouth of cnidarians called?
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What specialized cells do cnidarians contain for defense and capturing prey?
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What is a nematocyst?
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Nervous responses in cnidarians are controlled by a diffuse web of interconnected nerve cells called a ______.
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How many classes of cnidarians do scientists recognize?
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Study Notes
Porifera (Sponges)
- Commonly known as sponges, the phylum name Porifera derives from the numerous pores on their body surface.
- Sponges are simple aquatic animals classified under the phylum Porifera, linking unicellular to multicellular life forms.
- As sessile organisms, adult sponges attach to surfaces and do not move.
Invertebrates
- Invertebrates are animals lacking a backbone, encompassing over 1 million species, with sponges being a significant group.
Sponge Structure and Function
- The basic structure of a sponge includes two layers of cells separated by a jellylike substance known as mesophyll.
- The interior of the sponge cylinder is lined with flagellated cells called choanocytes, which play a key role in water filtration.
- Water enters the sponge through tiny pores called ostia and exits through a large opening known as the osculum.
- Sponges have a simple skeleton made of flexible fibers called spongins or spicules, which are hard particles of silicon dioxide.
Feeding Mechanism
- Sponges feed through filter feeding: Choanocytes beat their flagella to draw water in, trapping plankton and tiny organisms with their hair-like projections.
- Digested nutrients are distributed throughout the sponge by amoebocytes.
Reproduction in Sponges
- Sponges can reproduce both sexually and asexually.
- Asexual reproduction involves forming small buds that can break off, and gemmules that can develop into new sponges under favorable conditions.
- Sexual reproduction involves releasing sperm into the water, where they enter another sponge’s pores, with fertilization occurring in the mesophyll.
Cnidaria and Ctenophora
- Cnidaria and Ctenophora are phyla of more complex, radially symmetrical invertebrates, organized into tissues and possessing simple organs.
Cnidarian Structure
- Cnidarians have two cell layers: the outer epidermis and the inner gastrodermis, with mesoglea, a jellylike substance, located between them.
- The gastrovascular cavity serves as the mouth for cnidarians, surrounded by flexible extensions known as tentacles.
Cnidocytes and Nematocysts
- Cnidocytes are specialized cells in cnidarians used for defense and capturing prey, containing organelles called nematocysts.
- Nematocysts have coiled filaments that shoot out when triggered, injecting venom to subdue prey.
Nervous System in Cnidarians
- Cnidarians lack a centralized brain; instead, they have a diffuse nerve net, allowing for basic nervous responses distributed throughout their bodies.
Classes of Cnidaria
- Scientists categorize cnidarians into four classes, including Hydrozoa, Cubozoa, and Scyphozoa, each representing different groups and variations within the phylum.
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Description
Test your knowledge on sponges and their classification in the phylum Porifera with this engaging quiz. Learn about the characteristics and importance of these invertebrates, which make up a significant portion of the animal kingdom. Perfect for students studying biology or marine life.
