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Author Topic: Girlies are born with all their eggs !...why ?  (Read 6686 times)

Offline neilep

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Girlies are born with all their eggs !...why ?
« on: 01/09/2007 15:18:43 »
Will you take a look at this ?





Amazing eh ?... It IS actually hard to imagine that we start off as an eggy-weggy !!

Apparently girlie's are born already with all their eggs that they will ever use !

Why's that then ?
Why not just make one a month ?
Why are eggy-weggys so small ? Can they be seen with the naked eye ?
how do the eggs stay ' fresh ' for so many years ??


Are boys born already producing spermy-wermy ?



It's a good job chickens aren't born with all their eggs already !..they'd be huge !!


 

another_someone

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Girlies are born with all their eggs !...why ?
« Reply #1 on: 01/09/2007 17:19:53 »
I suspect that one advantage is that they are less vulnerable to viral infection that way - a virus can only infect a growing cell, and if the cell is dormant, it cannot be infected.
 

paul.fr

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Girlies are born with all their eggs !...why ?
« Reply #2 on: 01/09/2007 21:19:48 »
Are boys born already producing spermy-wermy ?[/b]


I don't know. but, at a few weeks old boys do geta massive burst of testosterone. It is (or was) thought that this was the body doing a "system check" to make sure all things work before puberty.
 

Offline JimBob

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Girlies are born with all their eggs !...why ?
« Reply #3 on: 01/09/2007 21:58:44 »
Ontogeny recapitulates phylogeny

That is just a fancy way of saying that when an organism develops from the first union of the gametes to adult stage it passes through all of the forms of the critters that are in the organism genetic lineage. Humans, for example, are chordates - they have backbones. The original back boned beasties were known as proto-chordates. Sometime during the Cambrian the proto-chordates made their debut. During the Ordovician fish-like creatures had appeared; the Devonian saw the first jawed fish and sharks, The Silurian the first bony fish, on and on to poor little short-lived (so far) humans. 

The human embryo as it develops goes through all of the stages, the egg forms, then folds to become a proto-chordate, then to something with gills, then on and on through amphibian and reptile like stages (these later stages are mostly seen in the development of the brain).

But even before there were proto-chordates, the survival strategy was to reproduce as fast as you can before your dead. So all types of animals, snails, squid, fish, frogs, insects, lobsters - all are born with all of the eggs they will ever have.

So does the human animal.
 

another_someone

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Girlies are born with all their eggs !...why ?
« Reply #4 on: 02/09/2007 03:06:26 »
Are boys born already producing spermy-wermy ?[/b]
I don't know. but, at a few weeks old boys do geta massive burst of testosterone. It is (or was) thought that this was the body doing a "system check" to make sure all things work before puberty.

Firstly, if you consider that a female human ovulates monthly for a period of about 40 years, thus she would need about 480 eggs to do this (she actually has a surfeit of eggs for her needs, but even a few thousand eggs is not unimaginable). 

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/Sexual_Reproduction.html
Quote
An adult male manufactures over 100 million sperm cells each day.

That is a lot more sperm that would need to be produced than eggs, and not practical to produce that many sperm in the embryo.

Secondly, while eggs (as far as I am aware) do not undergo any competitive selection process (there is normally only one egg available for fertilisation in a human female at any one time, so that egg had better not be diseased); the sperm do undergo a selection process as the race to reach the egg, and any sperm that has been weakened by infection is unlikely to win the race.  Thus there is less of a problem is some of the sperm are diseased, since other sperm will simply out compete it; while this situation is very different for the egg.

Incidentally, testosterone has many systemic effects long before puberty - including influencing IQ, and being responsible for the parts of a birds brain associated with bird song (although bird song is post puberty - but it does demonstrate the wide ranging effects that testosterone has on the brain).
« Last Edit: 02/09/2007 03:10:46 by another_someone »
 

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Girlies are born with all their eggs !...why ?
« Reply #4 on: 02/09/2007 03:06:26 »

 

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