Ctenophores Body Layers Quiz

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Questions and Answers

What is the primary function of colloblasts in ctenophores?

Secreting mucus

Capturing prey (correct)

Regulating muscle contraction

Locomotion

Which statement correctly describes the inner surface of the internal cavity in ctenophores?

It is lined with cilia only.

It contains no muscle cells.

It has a distinct type of gastrodermis. (correct)

It is primarily responsible for nutrient absorption.

What structure acts as the main support for the epidermal layers in ctenophores?

Mesoglea

Gastrodermis

Nerve net

Basement membrane (correct)

Which component is NOT typically found in the outer layer of the epidermis of ctenophores?

Muscle fibers Signup and view all the answers

In the anatomy of ctenophores, where do anal pores usually terminate?

Around the sensory complex Signup and view all the answers

What is the main dietary habit of ctenophores?

Carnivorous, mostly consuming other marine animals Signup and view all the answers

Which statement about ctenophores' method of capturing prey is accurate?

They employ a variety of techniques including using tentacles as webs. Signup and view all the answers

What feature is crucial for the locomotion of ctenophores?

Eight comb rows known as swimming-plates Signup and view all the answers

Which of the following prey can some ctenophores capture?

Relatively strong swimmers such as adult copepods Signup and view all the answers

What unique feature do some ctenophores acquire from their prey?

Nematocysts from cnidarians Signup and view all the answers

Which characteristic is unique to the anatomy of Ctenophores?

Biradial symmetry Signup and view all the answers

What distinguishes the tissue composition of Ctenophores?

Their structure consists of scatted cells in a jelly-like mesoglea. Signup and view all the answers

Which component is NOT part of the digestive system of Ctenophores?

Protonephridia Signup and view all the answers

Which statement about locomotion in Ctenophores is correct?

Locomotion is primarily achieved through the movement of cilia on comb rows. Signup and view all the answers

Which definition accurately describes biradial symmetry?

An organism can be divided into equal parts in only two planes. Signup and view all the answers

Which type of sensory organ is found at the aboral end of Ctenophores?

Statocyst Signup and view all the answers

What characteristic is NOT associated with Ctenophores?

They reproduce asexually. Signup and view all the answers

Which species of Ctenophore is characterized by a ribbon-like body?

Cestum Signup and view all the answers

What type of reproduction is common among Ctenophores?

Paedogenesis Signup and view all the answers

Which of the following statements regarding Ctenophore gonads is true?

They are endodermal and situated in the digestive canals. Signup and view all the answers

What role does the gastrodermis play in the digestion of prey?

It secretes enzymes that aid in digestion. Signup and view all the answers

How do cilia contribute to the nutrient transport in ctenophores?

They beat in a coordinated manner to move nutrients through the canal system. Signup and view all the answers

What is a unique feeding strategy employed by some ctenophores that consume cnidarians?

They incorporate undischarged cnidocytes into their epidermal tissue. Signup and view all the answers

Which statement best describes the waste removal process in ctenophores?

Most waste is regurgitated via the mouth. Signup and view all the answers

What feeding behavior is characteristic of ctenophores without tentacles?

They feed on gelatinous animals such as medusae or salps. Signup and view all the answers

What is the primary role of the cilia in the comb rows of ctenophores?

To generate waves for propulsion Signup and view all the answers

In what sequence does the ciliary beat occur in the comb rows of ctenophores?

Starts at the aboral end and moves to the oral end Signup and view all the answers

How does the swimming mechanism of ctenophores differ from that of jellyfish?

Ctenophores move in the direction of their mouth while feeding Signup and view all the answers

What structural feature contributes to the supportive function during the movement of ctenophores?

Combs or ctenes on the comb plates Signup and view all the answers

What pattern variation exists in the cilia arrangements in ctenophores?

Spacing patterns vary by species and are often uneven Signup and view all the answers

What type of symmetry allows an organism to be divided equally in only two planes?

Biradial symmetry Signup and view all the answers

Which of the following features is NOT present in comb jellies?

Nematocysts Signup and view all the answers

In which anatomical direction would you find the auricle of a comb jelly?

Aboral direction Signup and view all the answers

What type of sensory cells do comb jellies possess to aid in food capture?

Colloblasts Signup and view all the answers

Which of the following statements about comb jellies' reproductive system is accurate?

They are hermaphroditic with endodermal gonads. Signup and view all the answers

Study Notes

Body Structure of Ctenophores

Composed of a thick, jelly-like mesoglea sandwiched between two epidermal layers and an endodermis.
Outer epidermal layer contains sensory cells that secrete mucus and interstitial cells that can differentiate into other cell types.
Specialized outer epidermal cells include colloblasts for capturing prey and ciliated cells for locomotion.
Inner epidermal layer includes a nerve net and muscle-like specialized cells.
Internal cavity consists of a mouth, pharynx, stomach, and a branched canal system extending through the mesoglea.

Nutrition and Feeding

Cilia around the mouth direct water and prey into the cavity for digestion.
Prey digested in the pharynx using enzymes from the gastrodermis; muscle contraction aids digestion.
Nutrient transport facilitated by cilia within the canal system and nutritive cells.
Anal pores expel unwanted particles, with regurgitation being common for undersized matter.
Ctenophores with short tentacles feed on the ciliated body surface; those without may consume gelatinous animals.

Prey Capture Mechanisms

Various strategies employed for prey capture, including motionless web-like tentacles, ambush tactics, and sticky droplets to ensnare prey.
Capture methods vary, with some species targeting strong swimmers and others preferring weaker organisms.

Movement

Eight comb rows, or swimming-plates, equipped with cilia facilitate locomotion.
Cilia arranged in transverse rows create waves for propulsion, starting from the aboral pole toward the oral end.

Symmetry

Ctenophores exhibit biradial symmetry, allowing division into equal parts only in two planes, in contrast to radial symmetry.

Anatomical Features

Body structure varies in shape: pear-shaped, cylindrical, flat, or ribbon-like; all are transparent and gelatinous.
Lack of nematocysts; instead, they use adhesive cells called colloblasts for capturing prey.
Absence of skeletal, circulatory, respiratory, or excretory systems; possess a diffused nervous system with a statocyst as a sensory organ.
Monoecious reproduction with endodermal gonads located in digestive canal walls.

Diversity in Ctenophores

Notable species include:
- Beroe: Spherical body with mouth and statocyst.
- Cestum: Ribbon-like with a central mouth.
- Coeloplana: Flattened body with mouth on the underside.

Movement Dynamics

Ciliary beating initiates at the aboral end, creating a moving wave effect toward the oral end of the comb rows.
The organism can swim backward by reversing wave direction, allowing flexibility in movement.

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Description

Test your knowledge on the anatomical structure of ctenophores, focusing on their body layers including the unique mesoglea and epidermis. Explore the functions of sensory cells and the importance of cilia. Take this quiz to deepen your understanding of these fascinating marine organisms.