Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a...
Transcript of Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a...
![Page 1: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/1.jpg)
Intro to Meiosis
![Page 2: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/2.jpg)
What is it?
Who does it?
Where does it happen?
Why does it happen?
Why is a different process needed?
MeiosisMaking sex cells (sperm & eggs)
All sexually reproducing organisms
To allow organisms to reproduce
1) Chromosome # needs to be cut in half2) Creates genetic diversity (can help evolution of species)
In males- in the testesIn females- in the ovaries
![Page 3: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/3.jpg)
Diploid adult MITOSIS FERTILIZATION
MEIOSIS
Haploidgametes
Diploidzygote
Meiosis allows sex cells to join to form a completeset of chromosomes/instructions to make a new organism.
![Page 4: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/4.jpg)
Remember, humans have 23 pairs of chromosomes
Pairs 1-22 are said to beHomologous chromosomes(they go together becausethey have same traits but arenot identical)
Gene for eye color
Gene for hair color
![Page 5: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/5.jpg)
Now let’s look at how sex cells are made…
![Page 6: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/6.jpg)
Eight Stages of Meiosis1)Prophase I2)Metaphase I3)Anaphase I4)Telophase I
5)Prophase II6)Metaphase II7)Anaphase II8)Telophase II
![Page 7: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/7.jpg)
Prophase I: Crossing over occurs between replicated homologous chromosomes
Crossing over(exchanging parts)
![Page 8: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/8.jpg)
Note: chromosomes indaughter cells are all different
![Page 9: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/9.jpg)
Note: “X’s” are next to each other, not above each other
Metaphase I: Replicated chromosomes get next to each other in the cell
![Page 10: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/10.jpg)
Anaphase I: homologous chromosomes separate
![Page 11: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/11.jpg)
Telophase I: replicated chromosomes still need to be separated
still looks like an “X”
![Page 12: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/12.jpg)
Now Meiosis II occurs (looks like mitosis)
![Page 13: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/13.jpg)
Meiosis
![Page 14: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/14.jpg)
Meiosis animation
![Page 15: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/15.jpg)
Meiosis technical
And now let’s see a more technical version…
![Page 16: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/16.jpg)
One final detail…
![Page 17: Intro to Meiosis. What is it? Who does it? Where does it happen? Why does it happen? Why is a different process needed? Meiosis Making sex cells (sperm.](https://reader036.fdocuments.in/reader036/viewer/2022062719/56649ecb5503460f94bd98b7/html5/thumbnails/17.jpg)
The End!