Question

Answer in 40 to 80 words:
What is parthenogenesis? Give two examples.

Answer 1

Hint: The process in which a fruit or organisms is formed without fertilisation is known as parthenogenesis.
The fruit developed from parthenogenesis are known as false fruit. One such example of fruit is banana.

Complete answer:
It is a type of asexual reproduction. An unfertilized egg gets developed in new offspring. Males in this process do not play any significant role but only females get developed into offspring. It usually occurs in Honey bees and ants.
The sex-determination in honey bee is done according to the the number of sets of chromosomes an individual receives from male and female.
An offspring formed from the fusion of a sperm and an egg forms as a female (queen or worker),. and an unfertilized egg develops into a male (drone) by means of parthenogenesis.
It clearly means that the males possesses half the number of chromosomes than that of a female. The females are diploid and have 32 chromosomes and males are haploid ( half the number of females), i.e., having 16 chromosomes.
This type of sex determination is called as haplodiploid sex-determination system and has special characteristic features such as the males produce sperms by mitosis ,they do not have father and thus cannot have sons, but have a grandfather and can have grandsons.
When variations occur in populations they get eliminated by parthenogenesis. Polyploidy in organisms is the result of parthenogenesis. This process does not produce sterile organisms.

Note:
In parthenogenesis a embryo is formed but by only the genetic contribution of female and not by male.
There are many significance of parthenogenesis:
- It helps to determine sex of an individual in honey bees or wasps.
- It provides support to chromosomal theory of inheritance.