Oviparious

• About 97 percent of all fish reproduce by laying eggs, which means they are oviparious. No embryonic development occurs within the fish, which is a common reproductive method often seen in birds, reptiles, insects and amphibians. After the unfertilized eggs are laid, a male fish will swim by and fertilize them, allowing the eggs to grow to maturity.
  
  

Fish Organs

• The two main organs necessary for fish reproduction are the testes and ovaries, though the form of these organs is different than those of humans. In female fish, there are three types of ovaries -- in gymnovariun ovaries, oocytes are released into a cavity known as the coelomic cavity, which travel out through the oviduct using the ostium canal. In secondary gymnovian ovaries, the ova shed into the coelom cavity, then are passed directly through the oviduct. Cystovarian ovaries directly deposit oocytes through the ovidyct. The species of a female fish will dictate which type of ovary is present.
  
  

Viviparity

• Humans reproduce using a method known as placental viviparity. This means that the oocyte in a human is both fertilized and grown to maturity within the mother. The human reproductive system requires male fertilization of an egg while it is still inside the female. Placental viviparity is the method used by all mammals to reproduce.
  
  

Human Organs

• The human reproductive system relies on ovaries and testes as well, though human females have only one type of ovary. A human female reproductive system is made up of the ovaries, uterus, fallopian tubes, cervix, vagina and vulva. In humans, the ovaries release an oocyte, which travels through the fallopian tubes. Inside the uterus, the egg implants into the uterine lining if it is fertilized, otherwise the egg is expelled through the vagina. Male reproductive organs manufacture sperm in the testes, which is expelled through the penis.