1. Meiosis
Gametogenesis

2. Meiosis in Male and Female
In males is called spermatogenesis and produces sperm.
In females is called oogenesis and produces ova.

3. Spermatogenesis

4. Spermatogenesis The male gamete is called a spermatozoa
Four spermatocytes are formed during meiosis
Men are busy - meiosis produces roughly 250,000 sperm a day.

5. Oogenesis The female gamete is called an ovum
At birth each female carries a lifetime supply of developing oocytes, each of which is in Prophase I.
A developing egg (secondary oocyte) is released each month from puberty until menopause, a total of eggs.

6. Oogenesis Only one ovum is produced during meiosis
Oogenesis places most of the cytoplasm into the large egg. The other cells, the polar bodies, do not develop.

7. Human Fertilization
ZYGOTE – fertilized egg
Gametes

8. In Humans Example: 23 chromosomes in haploid n = 23
2n = 223 = ~ 6 million possible combinations!

9. Random fertilization
At least 6 million combinations from Mum and another 6 million from Dad …
>36 trillion combinations for a diploid zygote!!!

10. Any
Questions?