SEXUAL REPRODUCTION IN ANIMALS

Unlike a sexual reproduction, sexual reproduction involves 2 paires, in this type of reproduction 2 cells from different parent fuse to form a new individual. These cells which fuse are called gamete. They are form by a type of cell division called dash. After formation each cell  have exactly half the total number chromosomes as the parent cell. The gametes from the male parent is called the sperm. The gamete is from the female parent is called the egg the male gamete is usually active and move toward the female gamete. The female does not move but it is usually largerthan the male gamete and may contain food reserves. When the male and female gamate together they fuse in the process called fertilization to form zygote. The zygote undergoes repeated mitotic cell division developing into an embryo. The mbryo is the earliest stage of the development. Most organism have special reproduction or sex organ in which gamete are formed. This organs are called the gonands. The male gonads  produces the sperm while the female gonad produces an egg. The male gonad is the testis and the female gonad is the ovary. Many species of vertebrate are unisexual. They are either male or female but not both . inorder species individuals have both male and female reproductive organ and are same to be hermaphroditic hence they are called haemaphrodite some organism, the development of the embryo developing within the parent body and the offspring are borne alive in an advance stage of development this is kniwn as viviparity and the organism is said to be viviparus.