Phylum – Ctenophora: Notes and MCQs for Class 11 CBSE

Multiple Choice Questions

Introduction to Phylum – Ctenophora Characteristics of Ctenophora Reproduction in Ctenophora Examples of Ctenophora FAQs

Introduction to Phylum – Ctenophora

Ctenophores, commonly known as sea walnuts or comb jellies, are exclusively marine organisms. They exhibit radial symmetry and are diploblastic, meaning they have two germ layers. These organisms have a tissue level of organization.

Characteristics of Ctenophora

Marine Habitat: Ctenophores are found only in marine environments.
Radial Symmetry: Their bodies are radially symmetrical.
Diploblastic: Ctenophores have two germ layers.
Tissue Level of Organization: Their bodies are organized at the tissue level.
Ciliated Comb Plates: The body of a ctenophore bears eight external rows of ciliated comb plates, which aid in locomotion.
Digestion: Digestion in ctenophores is both extracellular and intracellular.
Bioluminescence: Ctenophores exhibit bioluminescence, the ability to emit light.

Reproduction in Ctenophora

Sexes: Ctenophores are not sexually dimorphic, meaning sexes are not separate.
Reproduction: Reproduction occurs exclusively by sexual means.
Fertilization: Fertilization is external, and development is indirect.

Examples of Ctenophora

Pleurobrachia: A common example of a ctenophore.
Ctenoplana: Another well-known example of this phylum.

FAQs

What are Ctenophores?

Ctenophores, also known as sea walnuts or comb jellies, are marine organisms that are radially symmetrical and diploblastic with a tissue level of organization.

How do Ctenophores move?

Ctenophores move using eight external rows of ciliated comb plates that help in locomotion.

What is bioluminescence in Ctenophores?

Bioluminescence in ctenophores is the ability of these organisms to emit light.

How do Ctenophores reproduce?

Ctenophores reproduce sexually, with external fertilization and indirect development.

Are sexes separate in Ctenophores?

No, sexes are not separate in ctenophores.