Invertebrate Zoology: Sponges and Coelenterates

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Questions and Answers

What is a defining characteristic of sponges?

Special cells called choanocytes

Radial symmetry

Gastric cavity with a single opening

Simple organization (correct)

Which sub-branch of Coelenterates is characterized by hermaphroditic organisms?

Nematoblasts

Ctenaria (correct)

Cnidaria

Hydra

What is the main mode of water exchange in sponges?

Peduncle

Cavities, canals, and holes (correct)

Tentacles

Gastric cavity

Which class does the freshwater hydra belong to?

Hydrozoan Signup and view all the answers

What is the function of special cells called colloblasts in Ctenaria?

Feeding by capturing prey Signup and view all the answers

What is the substance that bonds the two layers of the hydra's body together?

Mesoglia Signup and view all the answers

How does the hydra catch and paralyze its prey?

With tentacles that lead the prey to the mouth and cnidoblasts that secrete a paralyzing liquid Signup and view all the answers

Which part of Taenia saginata attaches to the human intestine?

Scolex or head equipped with 4 suction cups with hooks Signup and view all the answers

What is contained in each ring of Taenia saginata?

Male and female genitalia for fertilization Signup and view all the answers

What is the developmental stage of Taenia saginata that is swallowed by the intermediate host (bovine)?

Larva equipped with 3 pairs of hooks and surrounded by a shell Signup and view all the answers

Which of the following is true about Annelids?

They have a complete digestive tract with mouth and anus Signup and view all the answers

What is the distinguishing feature of Hirudinea among the Annelids?

Being exclusively parasitic Signup and view all the answers

Which statement is true about the leech's anatomy?

It has 5 pairs of eyes and 3 genital openings Signup and view all the answers

What is the primary mode of respiration in Annelids?

By diffusion through the body wall Signup and view all the answers

What distinguishes the circulatory system of Annelids from that of Nematodes (roundworms)?

Circulation driven by a central pump-like organ Signup and view all the answers

What distinguishes Oligochaetes from Polychaetes among Annelids?

Hermaphroditic reproduction Signup and view all the answers

What distinguishes Nemathelminthes (roundworms) from Annelids in terms of body covering?

Cylindrical body covered by a cuticle Signup and view all the answers

Which statement is true about Ascaris, a parasite of the human intestine?

It has a mouth with 3 lips and an excretory orifice Signup and view all the answers

Which feature distinguishes Annelids from Nemathelminthes in terms of reproduction?

Internal fertilization Signup and view all the answers

Study Notes

Sponges and Coelenterates

Sponges are characterized by a porous body and lack of true tissues and organs.
The subclass of Coelenterates known for hermaphroditic organisms is Hydrozoa.
Water exchange in sponges primarily occurs through a system of canals and pores, facilitating filtration feeding.

Hydra and Ctenaria

Freshwater hydra belongs to the class Hydrozoa within Coelenterates.
Colloblasts, special cells in Ctenaria, function to capture and immobilize prey using a sticky secretion.

Taenia Saginata

The scolex is the part of Taenia saginata that attaches to the human intestine.
Each proglottid, or segment, of Taenia saginata contains reproductive organs and gametes.
The larval stage of Taenia saginata consumed by the intermediate host (bovine) is the cysticerus.

Annelids and Their Features

Annelids are segmented worms that exhibit true coelom and a segmented body plan.
In the class Hirudinea (leeches), the distinguishing feature is the absence of setae (bristles) and the presence of suckers.
Leeches possess a flattened body structure and do not have a clitellum except during reproduction.
Respiration in Annelids primarily occurs through their skin via diffusion.

Circulatory and Reproductive Differences

Annelids have a closed circulatory system, whereas Nematodes have an open circulatory system without blood vessels.
Oligochaetes are distinguished from Polychaetes based on the presence of setae, with Oligochaetes having fewer and simpler setae.
Nemathelminthes, or roundworms, have a tough cuticle covering their bodies, distinguishing them from the softer, segmented bodies of Annelids.
Ascaris, a human intestinal parasite, is noted for its habit of living within the intestinal tract and systemic reproduction via eggs expelled in feces.

Reproductive Traits

A significant reproductive feature distinguishing Annelids from Nemathelminthes is that Annelids exhibit sexual reproduction with distinct male and female forms, while many Nematodes are often dioecious.

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Description

Test your knowledge of invertebrate zoology with a focus on the characteristics of sponges and coelenterates. Learn about their simple organization, symmetry, and unique cellular structures.