Which of the following situations correctly describes the similarity between an angiosperm egg and a human egg?

i. Eggs of both are formed only once in a lifetime

ii. Both the angiosperm egg and human egg are stationary

iii. Both the angiosperm egg and human egg are mobile

iv. Syngamy in both results in the formation of zygote

Choose the correct answer from the options given below:

The correct answer is iv only

Concept:

• Reproduction is the biological process by which a new form of life is produced from pre-existing similar life.
• Reproduction helps in the continuation of the species.
• There are two main modes of reproduction - Asexual and Sexual Reproduction
• Asexual reproduction:
  • Asexual reproduction does not involve the fusion of gametes.
  • The progeny formed through asexual reproduction are genetically identical to their parents.
  • Fragmentation, budding, binary fission, gemmule formation, etc. are some of the methods of asexual reproduction.
  • Spirogyra, Paramoecium, and Amoeba all reproduce asexually.
• Sexual reproduction:
  • Sexual reproduction involves the fusion of male and female gametes (haploid) to form the zygote (diploid).
  • Sexual reproduction involves two major events - Meiosis and the Fusion of gametes.
  • The progeny formed through sexual reproduction are genetically dissimilar. 
  • Humans, frogs, angiosperms, etc. show sexual reproduction.
  • In humans, the gametic cells are sperms (in males) and ova/egg (in females).
  • In angiosperms, the male gametophyte - sperm cells - are present inside the pollen grains and the female gametophyte - egg - is present inside the ovule.

Explanation:

• Statement I: Eggs of both are formed only once in a lifetime.
  • ​This statement is false.
  • In both angiosperms and in humans, the reproductive organs are active throughout the reproductive phase.
  • As a result, eggs are formed in both angiosperms and in humans (females) continuously during the reproductive phase.
  • Thus in both angiosperms and in humans, eggs are formed more than once in a lifetime.
• Statement II: Both the angiosperm egg and the human egg are stationary.
  • ​This statement is false.
  • An angiosperm egg is non-motile and hence it can be called stationary. In order for fertilization to take place, male gametophyte needs to be deposited on the stigma which is the part of the female reproductive whorl in the angiosperms. The male gametophyte is carried inside a pollen grain by the pollen tube.
  • In the case of humans, the human egg is motile. After ovulation, the ova/egg travels from the ovary to the fallopian tube where sperm if present can fertilize the egg. This movement is due to the beating action of the cilia that lines the female reproductive tract.
  • Thus the angiosperm egg is stationary but the human egg is motile and therefore not stationary.
• Statement III: Both the angiosperm egg and human egg are mobile.
  • ​This statement is false.
  • Angiosperm egg is non-motile. In order for fertilization to take place, male gametophyte needs to be deposited on the stigma which is the part of the female reproductive whorl in angiosperms. The male gametophyte is carried inside a pollen grain by the pollen tube.
  • In the case of humans, the human egg is motile. After ovulation, the ova/egg travels from the ovary to the fallopian tube where sperm if present can fertilize the egg. This movement is due to the beating action of the cilia that lines the female reproductive tract.
  • Thus the angiosperm egg is non-motile but the human egg is mobile.
• Statement IV: Syngamy in both results in the formation of a zygote.
  • This statement is true.
  • Syngamy refers to fertilization.
  • Fertilization is the process of the fusion of a haploid male gamete and a haploid female gamete to give rise to a diploid zygote.
  • Both angiosperms and humans reproduce sexually.
  • Fertilization is an important process that takes place during sexual reproduction that gives rise to a zygote.
  • Thus syngamy (fertilization) in both angiosperm egg and human egg results in the formation of a zygote.