Question

In oogamy fertilisation involves …………….
A. A small non-motile female, gamete and large motile male gamete
B. A large non-motile female gamete, and a small motile male gamete
C. A large non-motile female gamete and a small non-motile male gamete
D. A large motile female gamete and a small non-motile male gamete.

Answer 1

Hint: Sexual reproduction takes place through the fusion of gametes. Sexual reproduction takes place in algae by three methods-
> Isogamous reproduction - fusion of two gametes which are similar in size ,either flagellated or non flagellated is termed as isogamous . For example – Chlamydomonas ( gametes are flagellated and similar in size ) , spirogyra ( gametes are non flagellated and similar in size)
> Anisogamous reproduction – fusion of two gametes which are dissimilar in size is termed as anisogamous reproduction. for example – Chlamydomonas (some species)
> Oogamous reproduction- when a small motile male gamete fuses with a large non – motile female gamete, such type of reproduction is called oogamous reproduction and occurs in volvox and focus.

Complete answer:
> A small non-motile female, gamete and large motile male gamete:- In oogamous reproduction female gamete is large and hence the option is incorrect.
> A large non-motile female gamete, and a small motile male gamete:- in oogamous reproduction fusion between these type of gametes occurs hence the option is correct.
> A large non-motile female gamete and a small non-motile male gamete:- the male gamete should be motile, so the option is not correct.
> A large motile female gamete and a small non-motile male gamete.:- the female gamete should be non motile. hence the option is incorrect.

Our required answer is b that is A large non-motile female gamete, and a small motile male gamete.

Note: Algae are autotrophic organisms. They are chlorophyll containing simple , thalloid and autotrophic organisms. They are largely aquatic, either marine or freshwater. Algae reproduce by vegetative, asexual and sexual methods. Vegetative reproduction is by fragmentation. During asexual reproduction different type of spores are produces.