Basic terms in reproduction 

1. Reproduction : 

A Biological process in which new individuals are produced from existing individuals. It may or may not  involve fusion of gametes . Sometimes gametes are also not formed e.g. binary fission and budding . 

2. Gametes :

Gametes are specialised cells which are produced by male and female individuals in special organs called gonads and finally used in fertilization which is actual fusion of these  specialised cells. Female gamete is commonly known as egg and male gamete is called sperm.Generally gametes have haploid number of chromosomes for e.g. human gametes have 23 chromosomes where as other cells have 46 chromosomes. In some conditions they might show diploidy or aneuploidy ( different from normal chromosomes number).

3. Zygote 

A zygote is a diploid cell which is  produced when syngamy or fusion of male and female gametes occur . Zygote will develop into advanced stage " embryo " if provided with suitable conditions of growth . 

4. Fertilisation 

Fertilisation involves all events which lead to actual fusion of gametes or syngamy.It may occur inside or outside the female body . In frog it is external and in humans it is internal fertilisation which leads to development of zygote or new life .

5. Hermaphrodite 

A hermaphrodite is an animal which has both male and female gonads or gamete producing cells . Eg. Earthworm and leech .

6. Monoecious vs Dioecious 

Monoecious is the term used for plant  /trees and animals if they have both male and female gonads in same individual. China rose , mustard plant and earthworm 

Dioecious is term used in case female and male gonads occur in different individual in same species . For e.g. papaya plant and cockroach have different sexes . Testes is found in Male cockroach and ovaries are found in female cockroach. Similarly pollen grain are produced by male papaya plant and fruits are produced by ovaries of female papaya plant. Morphologically male and female individuals may be similar or dissimilar. For e.g. humans have sexual dimorphism. But it is difficult to identify male mulberry plant from female one until sexual maturity .