1. Plant lice can reproduce asexually, as well as a fish-carp species that was found in African lake where there were no males. In otherspecies of fish there is sex, but the sperm are physically prevented from entering the egg. The sperm, simply by their proximity and presence near the egg, stimulate cell division to begin and stimulte foetal growth simply by their presence nearby.
2. Note that the above process has also been observed in humans, where in certain highly romantic situations a man can get a woman pregnant by simply looking at her passionately and/or sitting next to her. It is thought that in that situation the man has what is called pre-ejaculatory sperm accumulating at the tip of his penis. This small pool of sperm somehow is transported, via air currents, or possibly finger contact, so that it manages to finds a path to the woman's vagina. This is a relatively rare process, which overcomes enormous obstacles of clothing and distance and more. For that reason this is thoght to be the original meaning of the phrase "Love Conquers All".
3. A woman can get pregnant without sperm, though this can only result in the birth of a girl (women do not posess the y chromosome needed to produce a baby boy).
4. Eggs can be fertilize without sperm by using somatic cells in the body. The cell has two sets of chromosomes, so need to separate the cell so it contains only one set of chromosomes to properly fertilze the egg.
5. Parthenogenisis is very rare in mammals - the rate of female humans born this way iS about 2 per million.
6. In Parthenogenisis the baby has the exact same, if not all, genetic material from the mother, and is like a clone.
7. For certain female species of the animal kingdom a small electrical charge is all that is needed to fertilize the egg.
8. Parthenogenisis has been performed in mice where two eggs were artifically fused to create a viable female fetus.
9. Animal kingdome examples of Parthenogenisis or asexual reproduction: Aphids & Whiptails (a type of lizard; genus: Aspidoscelis).
10. In a related form of asexual reproduction, called gynogenesis, the egg is stimulated to develop by the presence of sperm. However, none of the sperm's DNA is contributed to the offspring (for example, some salamanders in the genus Ambystoma).
11. A third type of asexual reproduction, called hybridogenesis is considered "hemiclonal"—1/2 the parents’ genome is passed to the offspring, i.e. the females mate w/ males & both contribute genetic material to their offspring, but when those offspring produce eggs, their father’s genetic material is discarded & the eggs have only their mother’s genes.
12. Flowers are NOT the only organisms that reproduce asexually. So can Fungi (NOT a plant), protozoans, bacteria, yeast, viruses, sponges (animals), some cnidarians, flatworms, etc.
(Reference: Firefly Encyclopedia of Reptiles & Amphibians, by Tim Halliday)
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