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Reproduction |
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HISTORY HABITAT SCIENTIFIC STUDY
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In two of the most common American Tardigrades, the Eutardigrada and the Heterotardigrada, the reproduce sexually. This means that a male and a female are needed to make new tardigradaes. In the Eutardigrada, gonoducts are released into the lower part of their intestine called the rectum. In the Heterotardigrada, gonoducts open to the outside of the body through an external reproductive pore. In some species of tardigradas scientists were unable to find any males. This means the tardigrades in this species reproduces asexually. Diploid tardigrada use a process called meiosis. In this process the female releases chromosomes into the oocytes and this results in a division of the cell. The cell eventually becaomes a full grown Diploid Tardigrada. In the Triploid Tardigrada oocytes are formed by meiosis. These oocytes become little triploid eggs that eventually hatch into Triploid Tardigrada. Sexual reproduction in Tardigrades may occur either externally or internally. As the female molts she may lay eggs inside of the shell. Afterwards a male will come along and fertilize the eggs with his semen. The shell protects the eggs from harm. This form is external because it occurs outside of the body. While a female Tardigrada is molting, a male will sometimes release his semen into a reproductive pore inside of the female's body there fertilization occurs inside of her ovaries. This process is internal because it occurs inside of the body.
*Gonoduct- reproductive cells innside of the female tardigrades body. *Oocytes- An immature female reproductive cell *Molt- The shedding of feathers, hair, or skin. (In this case it is the Water Bear's tough skin that is almost shell-like.) |