Chapter 36, Problem 1TYU

Summary Introduction

Introduction:

Parthenogenesis is a mode of asexual reproduction in which an egg develops into an embryo without fertilization.

Answer to Problem 1TYU

Correct answer:

Only a single parent is required for parthenogenesis, as fertilization is not needed. Hence, fertilization is not required for the development of an egg into an embryo. Therefore, option (D) is correct.

Explanation of Solution

Reason for the correct statement:

Parthenogenesis is observed in lower plants and animals. The egg or gamete produced by the female develops into a complete organism without fusion with the male gamete.

Option (D) is given as “An egg develops without being fertilized”.

“In parthenogenesis, an egg develops without being fertilized”. Thus, it is the right answer.

Hence, option (D) is correct.

Reasons for the incorrect statements:

Option (A) is given as “An individual may change its sex”.

An individual changing its sex is not parthenogenesis; it is called sequential hermaphroditism. Therefore, it is a wrong answer.

Option (B) is given as “Groups of cells grow into new individual”.

In parthenogenesis, a single egg develops into a complete organism, not from the groups of cells. Therefore, it is the wrong answer.

Option (C) is given as “An organism is first a male and then a female”.

An organism that develops as a male, and then develops into a female is called a protandrous hermaphrodite. Therefore, it is the wrong answer.

Hence, options (A), (B) and (C) are incorrect.

Conclusion

Parthenogenesis is an asexual mode of reproduction in which an organism develops from an unfertilized egg.