Question

Why do moss plants produce very large numbers of male gametes? Give one reason. What are these gametes called?

Answer 1

More number of gametes is for increasing the chances of fertilization. In mosses, the male gamete has to swim to the ovary. In the transportation process, many male gametes might die. So, more numbers of male gametes are produced.

Complete answer: In mosses, the gametes are produced on the gametophytes. The sperm ( or male gamete) are produced within tiny, typically stalked, club-shaped structures called antheridia. The sperms of male gametes of mosses are also called antherozoids. The stalk of the antheridium anchors the antheridium to the gametophyte. Each antheridium produces numerous male gametes in order to increase the chances of fertilization because the male gametes have to travel towards the female gamete which is present safely inside the archegonium. The eggs ( or female gametes) are produced in tiny, somewhat flask-like structures called archegonia. Each archegonium holds one egg (in a swollen section at its base, also known as the venter) and the male gametes enter through the channel in the narrower, tubular section (also known as the neck). On the side of the venter opposite the neck, the foot is present. The foot anchors the archegonium to the gametophyte. In the early stages of archegonial development, this channel does not exist and the area is filled with cells. While attaining maturity the cells in the center of the neck disintegrate to create the channel. The channel is filled with mucilage which results from the breaking down of the cells that initially occupied the channel.

Additional information:
A fertilized egg in an archegonium develops into a sporophyte. The sporophyte consists of a spore-containing capsule. The capsule, depending on the species, maybe stalked or stalkless. Each spore contains a mix of genes from the two parents. On successful germination, each spore will give rise to a new gametophyte.

Note: Once an antheridium has fully matured and contains viable male gametes, the gametes need to reach the eggs in archegonia. The first step is for the antherozoids to get out of the antheridia and the second is for them to travel to the archegonia and fertilize the egg within the archegonia. Water is essential for both steps.