Mitosis vs. Meiosis in animals spec. Humans also

[luckyyou13]

Hello all, and thank you for your time and knowledge on the subject matter.
(beware, I am new to posting within the forum

On the topic of Mitosis: I understand this process is used during regeneration, growth, cell duplication, healing things to this effect.
On the topic of Meiosis: I understand this process to be used during fertilization. I understand that the process yeilds 4 haploid cells from 1 diploid.

MISUNDERSTANDING/MISCOMPREHENSION:
1.When are the two used together?
2.Why are they used together?
3.During "Alternation of Generations" in plants, how and why to the two interchange?
4. During Meiosis, when I read about it, it speaks of the 2n sperm undergoing MI and MII to become 4 1n cells which then meet up with the 4 1n cells of the egg... how does this all occur? Where is this taking place (i.e) once the sperm and egg are in the site of embryonic development? Or prior to leaving the testies or ovaries?

I hope this is not too many questions as I have been over this, and still can not obtain clear picture.
Thank you again!
Lucky

[JackBean]

they are used together during the production of sex cells
http://faculty.clintoncc.suny.edu/facul ... eiosis.htm
go down to the gametogenesis
and that's because you cannot just divine your current cells with meiosis, but you still need to keep some precursors for futher gamete production

[Darby]

Many egg cells aren't technically egg cells when the sperm nucleus enters - in many animals, they delay meiosis I until afterward; in mammals, they're between I and II.