Gametophyte 

Spores germinate to give small but multicellular, free living, mostly photosynthetic thalloid gametophytes called “Prothallus”

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Mate choice and benefit

Mate choice increase the reproductive success.

Mate choice is result of sexual selection.

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Monogamy

Each individual mates exclusively with one partner over at least a single breeding cycle and sometimes for longer.

Monogamy occurs in fish, amphibians, reptiles, and mammals, but it is only commonly observed in birds, some rodents, and a few primate species.

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Several hypotheses explain the existence of monogamy.

1. Mate-guarding hypothesis, a male stays with a female to protect her from being fertilized by other males.

2. The male assistance hypothesis maintains that males remain with females to help them rear their offspring.

3. The female-enforced monogamy, females stop their male partners from being polygynous.

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Polygamy

Polygamy is a system in which either males or females' mate with more than one partner in a breeding season.

1. In polygyny

2. In polyandry

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Polygynous

In polygyny, one male mates with more than one female in a single breeding season, but females mate only with one male.

In species with male-male competition, males are often substantially larger than females, a phenomenon called sexual dimorphism.