Chapter 19, Problem 6STP

Summary Introduction

Introduction :

Members of the phylum Sarcodina are mostly free-living and mound in aquation habitats or damp soil. Nutrition is commonly holozoic. Their body is covered with plasmalemma. They develop a temporary protoplasmic outgrowth known as pseudopod. The pseudopod is the organ for locomotion.

Answer to Problem 6STP

Correct answer :

Option (B) feeding.

Explanation of Solution

Explanation/justification for the correct answer :

Option (B) feeding. Pseudopodia are used for locomotion and engulfing food particles. The receptors are present over the surface of the organism that can detect the food particles in its vicinity. The plasma membrane extends and forms pseudopodia to grab that food particle. It forms a vacuole around it. Digestive juices are poured into the vacuoles containing food particles. The digested food particle is then absorbed by the cytoplasm. The undigested particles are expelled out by running the whole process in reverse order.

  

Figure 1 A pseudopod formed by a member of the phylum Sarcodina

Explanation for incorrect answer :

Option (A) conjugation. It is a type of sexual reproduction that takes place in bacteria and some fungi. Members of the phylum Sarcodina do not reproduce through conjugation. However, sexual reproduction does take place through syngamy. Hence, it is an incorrect option.

Option (C) protection. During unfavorable conditions, members of the phylum Sarcodina protect themselves by forming cysts. Pseudopodia do not play any role in protection. Hence, it is an incorrect answer.

Option (D) reproduction. The members of the phylum Sarcodina reproduce asexually by binary fission, multiple fission, budding, and spore formation. In all these processes, pseudopod is not involved. Hence, it is an incorrect answer.