Tag: modes of reproduction

The reproductive cycle of the non-primate females is called oestrous cycle. For example, in rats, horse etc. It can be divided into four phases proestrus, estrus, metestrus and diestrus. The word estrus means heat. It is a sign of sexual receptivity and fertility.

On the basis number of estrous cycle (breeding cycle), females of some species can be monoestrous and diestrous. Monoestrous animals are those in which only one estrous cycle can be seen in a year. For example, dogs, fox etc. Whereas, diestrous animals are those in which two estrous cycles are seen in a year. For example, horse, goats etc. So, the correct option is A.

The reproductive cycle of the non primate females is called estrous cycle. For example, in rats, horse etc. It can be divided into four phases proestrus, estrus, metestrus and diestrus. Proestrus stage is the building up phase. The ovarian follicle becomes large and secretes estrogen which is necessary for the preparation of estrus and pregnancy. Estrus is the phase when ovulation takes place. It is also known as the period of heat and female is sexually receptive. Metestrus is the phase where corpus luteum forms under the influence of decreased estrogen and increased progesterone level. Diestrus is the phase where corpus luteum becomes functional and the progesterone level increases. So, the correct option is C.

The reproductive cycle of the non-primate females is called oestrous cycle. For example, in rats, horse etc. It can be divided into four phases proestrus, estrus, metestrus and diestrus. 

Estrous cycle is a reproductive cycle of females of non-primate vertebrates. The gap between two estrus periods is known as estrous cycle. The females are highly receptive during estrus period. It is an indication of breeding period because one or more periods of estrus may occur during the breeding season of a species. Polyoestrus are the animals which ovulates more than once in each breeding season. For example, rabbit. Cats are polyestrous but experience a seasonal anestrus in autumn and late winter. Horses are seasonal polyestrous. Humans have menstrual cycle they lack estrous cycle.

• Conjugation is merely the fusion of two compatible bacterial cells. Bringing two genotypes together and allowing them to conjugate is the equivalent of making a cross in eukaryotes.
• Our discussion of conjugation will center on the gut bacterium Escherichia coli ($E$. coli). Conjugation and gene transfer in $E$. coli are driven by a circular $DNA$ plasmids called the fertility factor or sex factor $(F)$, which is found in some but not all cells. Hence to understand how to make a cross in $E$. coli, we have to understand the properties of $F$.

Organisms produced by sexual reproduction have characters from both the parents and are not exactly identical to the parents.