1. Fig. 13-1
Sissy Spacek -- Mom from “Hot Rod”, Crazy old Mom in “The Help”

2. Sexual Reproduction VS Asexual Reproduction 0.5 mm Parent Bud
Fig. 13-2a
Sexual Reproduction VS
Asexual Reproduction
0.5 mm
Parent
Bud
(a) Hydra

3. Karyotype
Applications: Genetic Counseling

4. replicated chromosomes
Fig. 13-3b
TECHNIQUE: karyotype
5 µm
Pair of homologous
replicated chromosomes
Centromere
Sister
chromatids
Metaphase
chromosome
Male or Female?

5. KEY CONCEPT: Homologous Pair VS. Sister Chromatids Key Maternal set of
Fig. 13-4
KEY CONCEPT:
Homologous Pair
VS.
Sister Chromatids
Key
Maternal set of
chromosomes (n = 3)
2n = 6
Paternal set of
chromosomes (n = 3)
Two sister chromatids
of one replicated
chromosome
Centromere
Two nonsister
chromatids in
a homologous pair
Pair of homologous
chromosomes
(one from each set)

6. Simplified… we are not 2n=6…right?

7. Multicellular diploid adults (2n = 46)
Fig. 13-5
Key
Haploid gametes (n = 23)
Haploid (n)
Egg (n)
Diploid (2n)
Sperm (n)
MEIOSIS
FERTILIZATION
Ovary
Testis
Diploid
zygote
(2n = 46)
Mitosis and
development
Multicellular diploid
adults (2n = 46)

8. Meiosis occurs in all sexually reproducing organisms…
Fig. 13-6
Meiosis occurs in all sexually reproducing organisms…
Key
Haploid (n)
Haploid unicellular or
multicellular organism
Diploid (2n)
Haploid multi-
cellular organism
(gametophyte) n
Gametes n n
Mitosis n
Mitosis
Mitosis n
Mitosis n n n n n
MEIOSIS
FERTILIZATION
Spores n
Gametes n
Gametes n
MEIOSIS
FERTILIZATION
Zygote
MEIOSIS
FERTILIZATION 2n 2n 2n 2n
Diploid
multicellular
organism
Zygote
Diploid
multicellular
organism
(sporophyte) 2n
Mitosis
Mitosis
Zygote
(a) Animals
(b) Plants and some algae
(c) Most fungi and some protists

9. Fig. 13-7-1 Interphase Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes

10. Fig. 13-7-2 Interphase Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I 1
Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes

11. Fig. 13-7-3 Interphase Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I 1
Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes
Meiosis II 2
Sister chromatids
separate
Haploid cells with unreplicated chromosomes

12. -duplicated chromosomes
Fig
Interphase
Homologous pair of chromosomes
in diploid parent cell
One Interphase
-duplicated chromosomes
-sister chromatids form
TWO Divisions
M1 – divide homologs
M2 – divide sister chromatids
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I 1
Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes
Meiosis II 2
Sister chromatids
separate
Haploid cells with unreplicated chromosomes

13. -duplicated chromosomes
Fig
Interphase
Homologous pair of chromosomes
in diploid parent cell
One Interphase
-duplicated chromosomes
-sister chromatids form
TWO Divisions
M1 – divide homologs
M2 – divide sister chromatids
Chromosomes
replicate
1 x 2 = 2
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I 1
Homologous
chromosomes
separate
2 / 2 = 1
Haploid cells with
replicated chromosomes
Meiosis II 2
Sister chromatids
separate
1 / 2 = ½
Haploid cells with unreplicated chromosomes

14. -duplicated chromosomes
Fig
Interphase
Homologous pair of chromosomes
in diploid parent cell
One Interphase
-duplicated chromosomes
-sister chromatids form
TWO Divisions
M1 – divide homologs
M2 – divide sister chromatids
Chromosomes
replicate
1 x 2 = 2
2n x 2 = 4n (kind of not true…)
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Meiosis I 1
Homologous
chromosomes
separate
2 / 2 = 1
4n / 2 = 2n
Haploid cells with
replicated chromosomes
Meiosis II 2
Sister chromatids
separate
1 / 2 = ½
2n / 2 = n
Haploid cells with unreplicated chromosomes

15. SLIDES Or… VIDEO? Fig. 13-8 Prophase I Metaphase I Anaphase I
Telophase I and
Cytokinesis
Prophase II
Metaphase II
Anaphase II
Telophase II and
Cytokinesis
Centrosome
(with centriole pair)
Sister chromatids
remain attached
Centromere
(with kinetochore)
Sister
chromatids
Chiasmata
Spindle
Metaphase
plate
Sister chromatids
separate
Haploid daughter cells
forming
Homologous
chromosomes
Homologous
chromosomes
separate
Cleavage
furrow
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

16. Prophase I Metaphase I Anaphase I Centrosome (with centriole pair)
Fig. 13-8a
Telophase I and
Cytokinesis
Prophase I
Metaphase I
Anaphase I
Centrosome
(with centriole pair)
Sister chromatids
remain attached
Centromere
(with kinetochore)
Sister
chromatids
Chiasmata
Spindle
Metaphase
plate
Homologous
chromosomes
separate
Cleavage
furrow
Homologous
chromosomes
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

17. Prophase I Metaphase I Centrosome (with centriole pair) Centromere
Fig. 13-8b
Prophase I
Metaphase I
Centrosome
(with centriole pair)
Centromere
(with kinetochore)
Sister
chromatids
Chiasmata
Spindle
Metaphase
plate
Homologous
chromosomes
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

18. Telophase I and Cytokinesis
Fig. 13-8c
Telophase I and
Cytokinesis
Anaphase I
Sister chromatids
remain attached
Homologous
chromosomes
separate
Cleavage
furrow

19. Telophase II and Cytokinesis
Fig. 13-8d
Telophase II and
Cytokinesis
Prophase II
Metaphase II
Anaphase II
Sister chromatids
separate
Haploid daughter cells
forming

20. Fig. 13-8e
Prophase II
Metaphase II

21. Telephase II and Cytokinesis
Fig. 13-8f
Telephase II and
Cytokinesis
Anaphase II
Sister chromatids
separate
Haploid daughter cells
forming

22. DID YOU GET IT?

23. Cooperative Learning Meiosis: 2n = 8
6 groups of 4  4 groups of 6 => 4 Posters
Prophase I
Metaphase I
Anaphase I
Telophase I/Cyto.
Prophase II  Metaphase II
Anaphase II  Telophase II/Cyto.
Follow the Rubric…The 7th person is the facilitator
8th person is Interphase (words only) OR just helps Prophase with the crossing over!
What happens of note during interphase to prepare for M-phase?

25. Meiosis VS Mitosis

26. Replicated chromosome
Fig. 13-9a
MITOSIS
MEIOSIS
MEIOSIS I
Parent cell
Chiasma
Chromosome
replication
Chromosome
replication
Prophase I
Prophase
Homologous
chromosome
pair
2n = 6
Replicated chromosome
Metaphase
Metaphase I
Anaphase
Telophase
Anaphase I
Telophase I
Haploid
n = 3
Daughter
cells of
meiosis I 2n 2n
MEIOSIS II
Daughter cells
of mitosis n n n n
Daughter cells of meiosis II

27. Fig. 13-9b SUMMARY Property Mitosis Meiosis DNA replication
Occurs during interphase before
mitosis begins
Occurs during interphase before meiosis I begins
Number of
divisions
One, including prophase, metaphase,
anaphase, and telophase
Two, each including prophase, metaphase, anaphase, and
telophase
Synapsis of
homologous
chromosomes
Does not occur
Occurs during prophase I along with crossing over
between nonsister chromatids; resulting chiasmata
hold pairs together due to sister chromatid cohesion
Number of
daughter cells
and genetic
composition
Two, each diploid (2n) and genetically
identical to the parent cell
Four, each haploid (n), containing half as many chromosomes
as the parent cell; genetically different from the parent
cell and from each other
Role in the
animal body
Enables multicellular adult to arise from
zygote; produces cells for growth, repair,
and, in some species, asexual reproduction
Produces gametes; reduces number of chromosomes by half
and introduces genetic variability among the gametes

28. 3 Sources of Genetic Variation in Sexual Reproduction
1. Chromosome Recombination
2. Independent Orientation
3. Random Fertilization
NOTE:
1 & 2 are in Meiosis
3 is in Fertilization
Meiosis
Fertilization

29. Fig. 13-UN2 F H

30. Fig. 13-UN4

31. Source 1: Chromosome Recombination (AKA Crossing Over)
Fig
Source 1: Chromosome Recombination (AKA Crossing Over)
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs

32. Prophase I Nonsister of meiosis chromatids held together
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Chiasma
Centromere
TEM

33. Prophase I Nonsister of meiosis chromatids held together
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Chiasma
Centromere
TEM
Anaphase I

34. Prophase I Nonsister of meiosis chromatids held together
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Chiasma
Centromere
TEM
Anaphase I
Anaphase II

35. Recombinant chromosomes
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Chiasma
Centromere
TEM
Anaphase I
Anaphase II
Daughter
cells
Recombinant chromosomes

36. SOURCE 2: Independent Orientation
Fig
SOURCE 2: Independent Orientation
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
AKA Independent Assortment

37. Possibility 2 Possibility 1 Two equally probable arrangements of
Fig
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
Metaphase II

38. Possibility 1 Possibility 2 Two equally probable arrangements of
Fig
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
Metaphase II
Daughter
cells
Combination 1
Combination 2
Combination 3
Combination 4

39. Source 3: Random Fertilization
Fertilization is a random event with many possible outcomes. (223)
To determine the probability that any one sperm will fertilized any particular egg, you multiply the probability of the separate events together.
That is, 1 / 8 million X 1 / 8 million, which is a probability of less than 1 / 64 trillion.
Fertilization is a random event with many possible outcomes. To determine the probability that any one sperm will fertilized any particular egg, you multiply the probability of the separate events together. That is, 1 in over 8 million X 1 in over 8 million, which is a number greater that 1 in over 64 trillion.

40. Non-Disjunction
AKA Chromosomal Mutations
The failure of one or more pairs of homologous chromosomes (Meiosis I) or sister chromatids (Meiosis II) to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

42. Trisomy 21 = Down syndrome

43. Sex Chromosome Nondisjunction

44. STUDY / REVIEW Crash Course # 13 Meiosis: Where the Sex Starts
Amoeba Sisters -- Meiosis: The Great Divide
Bozeman Science – Phases of Meiosis

45. EXTRA CREDIT Stop Motion Video: Meiosis
See project rubric – 20 points Extra-credit!
Help from Bozeman Science

46. What are these three steps called?
Fig. 13-UN3
What are these three steps called? 1 2 3