Question

Meiosis during sperm formation of Ascaris, was first observed by
(a) Fleming
(b) Boveri
(c) Brauer
(d) De Vries
(e) Abbe

Answer 1

Hint: Sperm formation is also known as spermatogenesis in which sperms are made from spermatogonia which are present in the lining of the walls of the testis. Ascaris is a genus that belongs to roundworms and some of its species cause diseases in humans as well.

Complete Answer:
The process of spermatogenesis is as follows:
- Male germs cells or the spermatogonia cells divide in number by mitosis to form primary spermatocytes.

- These primary spermatocytes are made into secondary spermatocytes by meiosis-I which in turn undergo meiosis-II to form spermatids.
- Spermatids undergo further development to form the spermatozoa or sperms.
- This process was first observed by Brauer in Ascaris.

Additional information: Let us look at the other scientists mentioned in the options.
- Alexander Fleming was a Scottish physician who discovered penicillin, the first antibiotic from Penicillium notatum.
- Theodor Boveri proposed the chromosomal theory of inheritance along with Sutton. He also discovered centrioles of centrosomes in Ascaris.
- Hugo de Vries was a Dutch botanist who worked on the inheritance pattern in evening primrose and proposed that mutations are responsible for variation in a population.
- Lemaitre Abbe was a priest who proposed the theory of the expanding universe.
So, the correct option is ‘(c) Brauer’.

Note:
- Aschelminthes are known as roundworms because they appear round when a cross- section of their body is viewed.
- Aschelminthes are triploblastic, pseudocoelomate, and bilaterally symmetrical animals.
- Ascaris lumbricoides cause ascariasis in humans which is an infection of the intestines.
- Another roundworm which is known as the filarial worm (Wuchereria) causes elephantiasis in humans by affecting the lymphatic vessels of the lower limbs.