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Asexual reproduction

  1. Nov 10, 2014 #1
    Can parthenogenesis only perform by females ?and can produce females offspring only?
     
  2. jcsd
  3. Nov 11, 2014 #2

    Ryan_m_b

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    Staff: Mentor

    It can only occur in females given that the female of a species creates the egg. Parthenogenesis is the phenomenon whereby an unfertilised egg developes into a foetus and eventually adult organism. Eggs on their own are haploid so usually won't result in a viable offspring (though in some plants it can work). Generally the eggs are restored to being diploid and are clones of the mother. This isn't always the case though, in some species the egg, not the sperm, determines the sex of the offspring. In these species it is possible for a mother to give rise to a son through parthenogenesis.
     
  4. Nov 11, 2014 #3

    jim mcnamara

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  5. Nov 14, 2014 #4
    Hi Gracy.
    To produce offspring by parthenogenesis must have ovum. To produce ovum must have ovary. Having ovary means we have a female. So if your question refer to females and males and which of them give parthenogenesis, it is like this question : Is red color, red ? Yes. Between male and female , only female gives parthenogenesis. If male performed parthenogenesis (give ovum) we call it female, because it would have ovary. But there is not only females and males. There are also hermaphrodites. For example in Icerya purchasi Maskell , (a cocoeides) normal men are rare. Almost all individuals are outside like females and their reproductive system is almost like a female's reproductive system of related to them species, but gonad which is made from the fusion of two originally separate organs, produce ovum (from external cells) and spermatozoa (from internal cells). Usual reproduction is made by fertilization (inside the gonad) , of ovum by spermatozoa ,by selfing, but some times ovum, gives by parthenogenesis, haploids males. As you see , parthenogenesis can perform not only by females, but also by hermaprodites and they can produce not only female offspring but males (haploids, clones) Similar case of functional Hermaphroditism obtain in Icerya bimaculata. As for case of parthenogenesis performed by females, offspring can be female or male. In Optional Haploid Harrenotokos Parthenogenesis female gives fertilized (diploids) which gives females and not fertilized (haploids) which gives males. In Optional Thylitokos Parthenogenesis , the ovum's nucleus which has not fertilized come back to diploid with fusion with the second polar corpuscle and gives only females (this case obtain in some Symphyta, Fasmoides and Tetrigidae.) In Obligatory Thylitokos Parthenogenesis there are no males or they are very rare and sometimes inactive. At last in Circular Parthenogenesis were gendered generations interpolate between generations with obligatory parthenogenesis, in some Aphides, females gives (by parthenogenesis) both males and females. In Species of Genus Phylloxera there are two types of females who perform parthenogenesis. One type gives small eggs which gives males and the other type give big eggs which gives females. In Cynipidae, individuals of the parthenogenetic generation are of two types : one type gives males and the other give females or each female (which perform parthenogenesis) produces males and females in a ratio that vary upon species.
     
  6. Nov 16, 2014 #5
    In insects, parthenogenesis is often caused by bacterial symbionts. The bacteria Wolbachia are especially well known for this, but there are others.

    These bacteria are transmitted from mother to offspring, but not father to offspring, so it is more advantageous for them if they skew the female:male offspring ratio towards females. Parthenogenesis is one method to accomplish this, although I'm not sure if it requires a haploid-diploid sex determination system, which itself might be an adaptation against these types of sex ratio influencing bacterial symbionts.
     
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