Question

what is the difference between delayed fertilization and delayed implantation? Give an example of each.

Answer 1

Delayed implantation is a reproductive strategy used by approximately 100 different mammals in seven or eight different orders. In embryonic diapause, the embryonic blastocyst does not immediately implant in the uterus after sexual reproduction has created the zygote, but rather remains in a state of dormancy. Little to no development takes place while the embryo remains unattached to the uterine wall. As a result, the normal gestation period is extended for a species-specific time.While much of the molecular regulation involved in activating dormant blastocysts has been characterized, little is still known about entry into diapause, and the conditions which enable a blastocyst to remain dormant.Some mammals that undergo embryonic diapause include rodents, bears,mustelids (e.g. weasels and badgers), and marsupials, (e.g. kangaroos).

Delayed development Period of suspended or slow growth of the embryo that can occur after implantation has occurred but prior to birth. Delayed  ovulation is a type of delayed fertilization whereby ovulation is delayed, resulting in fertilization also being delayed.

Most carnivores can pause their pregnancies, including all bears  and most seals, but so can many rodents, deer, armadillos, and anteaters. More than a third of the species that take a breather during gestation are from Australia, including some possums and all but three species of kangaroo and wallaby.