What hypotheses have been proposed to explain parthenogenesis?

Answer 1

The phenomenon of parthenogenesis was discovered in the 18th century by Charles Bonnet. In 1900, Jacques Loeb accomplished the first clear case of artificial parthenogenesis when he pricked unfertilized frog eggs with a needle and found that in some cases normal embryonic development ensued. Artificial parthenogenesis has since been achieved in almost all major groups of animals.

Parthenogenesis (which means “virgin birth”) describes the growth and development of an embryo or seed without fertilization by a male which the females produce eggs.
Parthenogenesis occurs in some fishes, several kinds of insects, and a few species of frogs and lizards. It does not normally occur in mammals because of their imprinted genes. In a few non-mammalian species it is the only method of reproduction, but more commonly, animals turn to parthenogenesis only at certain times. Reproduction by parthenogenesis is more rapid than sexual reproduction, and the use of this mode of asexual reproduction permits the animals to quickly exploit the available resources. Also, Parthenogenesis is forced on some species of wasps called the “Wolbachia”, when they become infected with bacteria. They can pass to a new generation through eggs, but not through sperm, so it is advantageous to the bacterium for females to be made rather than males.

Answer 2

it's a real thing..so, by this point it's not a hypothesis. You could look at animals that do parthenogenesis. Certain reptiles do it.