1. Reproduction: Asexual vs. Sexual

2. What is asexual reproduction?
One parent producing an offspring identical to itself.

3. Genetic Variation
There is no variation in genetics. The offspring are identical to parent.

4. In What Type of Organisms does asexual reproduction occur?
Single celled organisms, (bacteria)
The body cells of multi-cellular organisms,
(ALL Non-Sex Cells!)

5. Example:
Skin cells reproducing Bacteria dividing

6. Asexual Reproduction:
Purpose: Produce genetically
identical offspring

7. Advantages of Asexual Reproduction
Quick, Simple, Offspring are identical to the parent (Ex. Skin cells produce skin cells!)

8. Disadvantages of Asexual Reproduction
NO DIVERSITY! What can harm one organism, can harm all!

9. Binary Fission
A form of asexual reproduction used by all prokaryotes

10. Mitosis

11. Cell Division: Mitosis
Process: Cell division
Purpose: Create two genetically identical cells
Cells types:
Body Cells / Somatic Cells
(ALL Non-Sex Cells)

12. Cell Division: Mitosis
Type of Reproduction: Asexual
# of Parent Cells: One
# of Daughter Cells (Offspring): Two
Genetic Material:
Offspring DNA is
Identical to parent

13. Cell Division: Mitosis
Types of Organisms: Single-Celled organisms, bacteria, Body cells
# of Cell Divisions: One

14. Cell Division: Mitosis
Sets of Chromosomes: Full (2n),
Diploid (Human= Start 46, End 46)
# of Chromosomes: Full (2n), Diploid
Amount of DNA: Full, complete set of organisms chromosomes

15. Mitosis How non-sex cells reproduce (skin, intenstine, blood etc)
Starts with one parent cell
Ends with two daughter cells
Daughter cells are genetically identical

16. Sexual Reproduction & Meiosis

17. Sexual Reproduction
What is it? Creating a new organism by combining the genetic material of two organisms.

18. Sexual Reproduction
Genetic Variation The offspring is genetically unique from either parent

19. Sexual Reproduction
What organisms reproduce sexually? (& Examples) Multi-cellular organisms: Plants & Animals

20. Sexual Reproduction
Purpose Create genetically diverse offspring.

21. Sexual Reproduction
Advantages A diverse population can better adapt to changes in the environment & avoid extinction

22. Sexual Reproduction
Disadvantages -Takes longer to produce offspring -Need to find a mate

24. Meiosis: Creating Sex Cells

25. Meiosis
Process: Sex Cell Division Purpose: Create sex cells (gametes) Type of Cell: Gametes (sperm & egg) Type of Reproduction: Sexual

26. Meiosis
# of Parent Cells: 1 # of Daughter Cells: 4 Genetic Material At End: Each of the 4 daughter cells will be unique from the parent and other daughter cells

27. Meiosis
Type of organisms: Multi-cellular organisms; male and female # of Cell Divisions: 2

28. Meiosis Sets of Chromosomes: Creates cells with 1 set of chromosomes.
Known as ‘haploid cells’ (1n)

29. Meiosis # of Chromosomes:
Sex cells have half the # of chromosomes as somatic cells
(Human: 23 sperm, 23 egg)

30. Meiosis
Amount of DNA:
Half the amount of DNA (haploid, 1n)

32. 13. Genetic Variation: Crossing Over
Crossing over = Chromosome pairs exchanging segments of DNA
This creates genetic variation.

33. Oogenesis- formation of ovum (egg cells)
Female mammals are believed to be born with finite number of potential eggs
7 million at 20 weeks of gestation
1-2 million at birth
400,000 at puberty
~500 will be released in their lifetime
Few if any complete meiosis

34. Spermatogenesis- formation of sperm cells
Begins at puberty, ends at death
One spermatocyte yields four spermatazoa
Process takes about 64 days
170 million sperm made a day