Charles Bonnet discovered the process of parthenogenesis.
Abraham Trembley was the first to study the concept of Regeneration in the Hydra.

In Vivipary, the embryo develops inside the womb of females body, hence they are nourished by the mother through the placenta.

Incomplete parthenogenesis is a type of reproduction in which both sexual reproduction and parthenogenesis occur. Example: In honey bees, the fertilized eggs develop into a queen bee and worker bees, whereas the unfertilized eggs develop into drones (male).

(a) Arrhenotoky: In this type, only males are produced by parthenogenesis. eg: honey bees
(b) Thelytoky: In this type of parthenogenesis only females are produced by parthenogenesis. e.g: Solenobia
(c) Amphitoky: In this type parthenogenetic egg may develop into individuals of any sex. e.g: Aphis.

In the tapeworm, Taenia solium the gravid (ripe) proglottids are the oldest at the posterior end of the strobila. The gravid proglottids are regularly cut off either singly or in groups from the posterior end by a process called apolysis. This is very significant since it helps in transferring the developed embryos from the primary host (man) to find a secondary host (pig).

(i) Longitudinal binary fission
(ii) Euglena

Oviparous animals lay eggs outside their body. These eggs are exposed to various environmental conditions and may be eaten by predators also. They face lot of risks until the young ones hatche. But the offsprings of viviparous animals are more safe and protected in the maternal womb until they are born.

1. In unicellular organism there is no special structure for reproduction.
2. In binary fission the entire parent body constitute the reproductive unit and disappears when its division into two daughter unicellular cell is completed.
3. These two daughter cells function as two new individuals.
4. There is no remains of parent body cell and parent cannot be said to have died.
5. In fact after binary fission parent continues living as two daughter individual.
Hence, the unicellular organisms which undergo binary fission are called immortal (no natural death).

Offsprings produced by asexual reproduction are called clones, because they are genetically as well as morphologically similar to the parent organism.
They are not only similar to one another, but are also exact copies of their parent (e,g): Amoeba, Spirogyra, Hydra, Yeast, etc.

(a) Some organisms like honeybees are called parthenogenetic animals.
1. In case of honeybees both haploid and diploid individuals formed, as a result of incomplete parthenogenesis.
2. Both sexual reproduction and parthenogenesis are inclusive.
3. Fertilized eggs (zygote) give rise to queen and workers (both are females) by the process of sexual reproduction.
4. Unfertilized eggs (ova) of females develop into drones (males) by the process of parthenogenesis.
(b) A male honeybee has 16 chromosomes where as its female has 32 chromosomes
1. It is because of haplodiploidy which is a sex determination system, in which males develop from unfertilized eggs (parthenogenesis) and are haploid (16n) and females develop frorn fertilized eggs and are diploid (32n) (sexual reproduction).
2. As unfertilized egg carries only half number of chromosome as compared to fertilized egg.
Therefore male honeybees have 16 chromosomes where as female has 32 chromosomes.