The cleavage activity is intrinsic to RNA polymerase itself, it is stimulated greatly by accessory factors that are ubiquitous in the three biological kingdoms. There are two such factors in E. coli, GreA and GreB, and eukaryotic RNA polymerase II uses TFIIS for the same purpose. 

TLS Online TPP Program

#Id: 9431

#Unit 11. Evolution and Behavior

Bateman put several males and females together in bottles for several days. 

He concluded that the number of offspring sired by a male increased in proportion to the number of females he mated.

In contrast, the number of offspring produced by a female did not increase with the number of males she mated.

TLS Online TPP Program

#Id: 9432

#Unit 11. Evolution and Behavior

The outcome of sexual selection is strongly influenced by the operational sex ratio

TLS Online TPP Program

#Id: 9433

#Unit 11. Evolution and Behavior

Mate choice and benefit

Mate choice increase the reproductive success.

Mate choice is result of sexual selection.

TLS Online TPP Program

#Id: 9434

#Unit 11. Evolution and Behavior

TLS Online TPP Program

#Id: 9435

#Unit 11. Evolution and Behavior

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.

TLS Online TPP Program

#Id: 9436

#Unit 11. Evolution and Behavior

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.