1. CHARACTERISTICS OF LIVING THINGS
Remember:
CHARACTERISTICS OF LIVING THINGS
All Living things reproduce

2. Asexual Reproduction
Bacteria reproduce using
Binary Fission

3. PRODUCES CELLS THAT ARE IDENTICAL COPIES OF PARENT CELL
Binary Fission & Mitosis

4. Asexual Reproduction Advantages Disadvantages
Can make offspring faster
Don’t need a partner
Disadvantages
Species CAN’T change and adapt
One disease can wipe out whole population

5. Sexual Reproduction Combines genetic material
from 2 parents (sperm & egg)
so offspring are
genetically DIFFERENT from parents

6. + EGG SPERM  If egg and sperm had same number of
Zygote (One celled organism that has 46 chromosomes)
If egg and sperm had same number of
chromosomes as other body cells . . .
baby would have too many chromosomes!

7. Sexual Reproduction ADVANTAGES DISADVANTAGES
Allows for variation in population
Individuals are different
Provides foundation for EVOLUTION
Allows species to adapt to changes in their environment
Takes longer to reproduce
Need a mate
Mutations can occur easily

8. MEIOSIS is the way… to make cells with ½ the number of chromosomes
for sexual
reproduction

9. HOMOLOGOUS CHROMOSOMES
MOST CELLS HAVE 2 COPIES OF EACH CHROMOSOME = DIPLOID 2N (ONE FROM MOM; ONE FROM DAD) ALL BODY (SOMATIC) CELLS ARE DIPLOID
HOMOLOGOUS CHROMOSOMES
DIPLOID & HAPLOID

10. Diploid & Haploid Cells
Some cells have only one copy of each chromosome = HAPLOID 1n
All sperm and egg cells
are haploid

11. REMEMBER MITOSIS
Makes 2 cells genetically IDENTICAL to parent cell & to each other
Makes 2n cells
Makes SOMATIC (body) cells
Used by organisms to: increase size of organism, repair injuries, replace worn out cells

12. MEIOSIS
Makes 4 cells genetically different from parent cell & from each other
Makes 1n cells
Makes GERM CELLS or GAMETES (sperm & egg)
Used for SEXUAL REPRODUCTION

13. Lets Take a Closer look at Meiosis
MITOSIS: G1 S G2 P M A T C       
MEIOSIS: G1 A T C
( I ) S G2 P M        P M A T C
( II ) 

14. MEIOSIS l

15. Meiosis ll Prophase II Metaphase II Anaphase II Telophase II
Meiosis I results in two haploid (N) daughter cells, each with half the number of chromosomes as the original.
The chromosomes line up in a similar way to the metaphase stage of mitosis.
The sister chromatids separate and move toward opposite ends of the cell.
Meiosis II results in four haploid (N) daughter cells.

16. http://www.youtube.com/watch?v=D1_- mQS_FZ0

17. WHAT MAKES MEIOSIS DIFFERENT ?
SYNAPSIS & CROSSING OVER (PROPHASE I)
SEGREGATION &
INDEPENDENT ASSORTMENT (ANAPHASE I)
3. Skip INTERPHASE II (NO S)
CELL DIVIDES TWICE, BUT…
ONLY COPIES DNA ONCE

18. WHAT MAKES MEIOSIS DIFFERENT ?
Homologous chromosomes pair up during PROPHASE l = SYNAPSIS
This group of FOUR (4)
chromatids is called a
TETRAD (4)

19. WHAT MAKES MEIOSIS DIFFERENT?
1. Exchange of DNA between homologous pairs = _____________ during PROPHASE l
CROSSING OVER
Allows shuffling of genetic material
(more variation
Between organisms)

20. HOMOLOGOUS CHROMOSOMES
SAME SIZE
SAME SHAPE
CARRY GENES for the SAME TRAITS
BUT NOT IDENTICAL!
(Don’t have to have the SAME CHOICES)

21. CROSSING OVER rearranging of DNA Allows for_________________
in different combinations
After crossing over, chromatid arms are________________ anymore
NOT IDENTICAL

22. WHAT MAKES MEIOSIS DIFFERENT ?
2.Separation during ANAPHASE I
SEGREGATION &
INDEPENDENT ASSORTMENT
Separates gene choices and allows shuffling of genetic material

23. SEGREGATION (Anaphase I)