In nature asexual reproduction occurs in only one parent and in the absence of fertilization of gametes. Many single-cell organisms primarily reproduce asexually, although most of them are capable of exchanging genetic material with other individuals via various processes such as the complete merging of two separate organisms in a process called "conjugation". Asexual reproduction also occurs sparodically in various species of all the kingdoms of life, even including some vertebrates - for example, a species of shark (hammerhead) has been recently found able to to self-fertilize and produce progeny in the absence of males. This process is called parthenogenisis, from the Greek words for "virgin birth".
- MSNBC "Female sharks capable of virgin birth" Accessed July 1, 2007
- Asexual Visibility and Education Network