1. Fig. 13-1
Figure 13.1 What accounts for family resemblance?

2. 0.5 mm Parent Bud (a) Hydra (b) Redwoods Fig. 13-2
Figure 13.2 Asexual reproduction in two multicellular organisms
Parent
Bud
(a) Hydra
(b) Redwoods

3. 0.5 mm Parent Bud (a) Hydra Fig. 13-2a
Figure 13.2 Asexual reproduction in two multicellular organisms
Parent
Bud
(a) Hydra

4. Fig. 13-2b
Figure 13.2 Asexual reproduction in two multicellular organisms
(b) Redwoods

5. Figure 13.3 Preparing a karyotype
APPLICATION
Figure 13.3 Preparing a karyotype
TECHNIQUE
5 µm
Pair of homologous
replicated chromosomes
Centromere
Sister
chromatids
Metaphase
chromosome

6. Fig. 13-3a
APPLICATION
Figure 13.3 Preparing a karyotype

7. TECHNIQUE 5 µm Pair of homologous replicated chromosomes Centromere
Fig. 13-3b
TECHNIQUE
5 µm
Pair of homologous
replicated chromosomes
Centromere
Figure 13.3 Preparing a karyotype
Sister
chromatids
Metaphase
chromosome

8. Key Maternal set of chromosomes (n = 3) 2n = 6 Paternal set of
Fig. 13-4
Key
Maternal set of
chromosomes (n = 3)
2n = 6
Paternal set of
chromosomes (n = 3)
Two sister chromatids
of one replicated
chromosome
Figure 13.4 Describing chromosomes
Centromere
Two nonsister
chromatids in
a homologous pair
Pair of homologous
chromosomes
(one from each set)

9. Multicellular diploid adults (2n = 46)
Fig. 13-5
Key
Haploid gametes (n = 23)
Haploid (n)
Egg (n)
Diploid (2n)
Sperm (n)
MEIOSIS
FERTILIZATION
Figure 13.5 The human life cycle
Ovary
Testis
Diploid
zygote
(2n = 46)
Mitosis and
development
Multicellular diploid
adults (2n = 46)

10. Figure 13.6 Three types of sexual life cycles
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 n
Figure 13.6 Three types of sexual life cycles
Gametes
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

11. Key Haploid (n) Diploid (2n) Gametes n n n MEIOSIS FERTILIZATION
Fig. 13-6a
Key
Haploid (n)
Diploid (2n)
Gametes n n n
MEIOSIS
FERTILIZATION
Figure 13.6a Three types of sexual life cycles—animals
Zygote 2n 2n
Diploid
multicellular
organism
Mitosis
(a) Animals

12. (b) Plants and some algae
Fig. 13-6b
Key
Haploid (n)
Haploid multi-
cellular organism
(gametophyte)
Diploid (2n)
Mitosis
Mitosis n n n n n
Spores
Gametes
Figure 13.6b Three types of sexual life cycles—plants and some algae
MEIOSIS
FERTILIZATION 2n 2n
Zygote
Diploid
multicellular
organism
(sporophyte)
Mitosis
(b) Plants and some algae

13. Haploid unicellular or multicellular organism Diploid (2n)
Fig. 13-6c
Key
Haploid (n)
Haploid unicellular or
multicellular organism
Diploid (2n)
Mitosis
Mitosis n n n n
Figure 13.6c Three types of sexual life cycles—most fungi and some protists
Gametes n
MEIOSIS
FERTILIZATION 2n
Zygote
(c) Most fungi and some protists

14. Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Interphase
Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number

15. Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Interphase
Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Meiosis I 1
Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes

16. Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Interphase
Homologous pair of chromosomes
in diploid parent cell
Chromosomes
replicate
Homologous pair of replicated chromosomes
Sister
chromatids
Diploid cell with
replicated
chromosomes
Figure 13.7 Overview of meiosis: how meiosis reduces chromosome number
Meiosis I 1
Homologous
chromosomes
separate
Haploid cells with
replicated chromosomes
Meiosis II 2
Sister chromatids
separate
Haploid cells with unreplicated chromosomes

17. Figure 13.8 The meiotic division of an animal cell
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
Figure 13.8 The meiotic division of an animal cell
Sister chromatids
separate
Haploid daughter cells
forming
Homologous
chromosomes
Homologous
chromosomes
separate
Cleavage
furrow
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

18. 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
Figure 13.8 The meiotic division of an animal cell
Cleavage
furrow
Homologous
chromosomes
Homologous
chromosomes
separate
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

19. 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
Figure 13.8 The meiotic division of an animal cell
Homologous
chromosomes
Fragments
of nuclear
envelope
Microtubule
attached to
kinetochore

20. Telophase I and Cytokinesis
Fig. 13-8c
Telophase I and
Cytokinesis
Anaphase I
Sister chromatids
remain attached
Figure 13.8 The meiotic division of an animal cell
Homologous
chromosomes
separate
Cleavage
furrow

21. Telophase II and Cytokinesis
Fig. 13-8d
Telophase II and
Cytokinesis
Prophase II
Metaphase II
Anaphase II
Figure 13.8 The meiotic division of an animal cell
Sister chromatids
separate
Haploid daughter cells
forming

22. Prophase II Metaphase II Fig. 13-8e
Figure 13.8 The meiotic division of an animal cell

23. Telephase II and Cytokinesis
Fig. 13-8f
Telephase II and
Cytokinesis
Anaphase II
Figure 13.8 The meiotic division of an animal cell
Sister chromatids
separate
Haploid daughter cells
forming

24. Figure 13.9 A comparison of mitosis and meiosis in diploid cells
Parent cell
Chiasma
Chromosome
replication
Chromosome
replication
Prophase
Prophase I
Homologous
chromosome
pair
Replicated chromosome
2n = 6
Metaphase
Metaphase I
Anaphase
Anaphase I
Telophase
Telophase I
Haploid
Figure 13.9 A comparison of mitosis and meiosis in diploid cells
n = 3
Daughter
cells of
meiosis I 2n 2n
MEIOSIS II
Daughter cells
of mitosis n n n n
Daughter cells of meiosis II
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,
anahase, 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 amoung the gametes

25. Replicated chromosome
Fig. 13-9a
MITOSIS
MEIOSIS
MEIOSIS I
Parent cell
Chiasma
Chromosome
replication
Chromosome
replication
Prophase
Prophase I
Homologous
chromosome
pair
2n = 6
Replicated chromosome
Metaphase
Metaphase I
Figure 13.9 A comparison of mitosis and meiosis in diploid cells
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

26. Figure 13.9 A comparison of mitosis and meiosis in diploid cells
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
Figure 13.9 A comparison of mitosis and meiosis in diploid cells
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

27. Two of three possible arrange- ments of labeled chromosomes
Fig
EXPERIMENT
Shugoshin+ (normal)+
Shugoshin–
Spore case
Fluorescent label
Metaphase I
Anaphase I
Metaphase II OR
Anaphase II ? ? ? ?
Figure What prevents the separation of sister chromatids at anaphase I of meiosis?
Mature
spores ? ? ? ?
Spore
Two of three possible arrange-
ments of labeled chromosomes
RESULTS
100 80
Spore cases (%) 60 40 20
Shugoshin+
Shugoshin–

28. Two of three possible arrange- ments of labeled chromosomes
Fig a
EXPERIMENT
Shugoshin+ (normal)
Shugoshin–
Spore case
Fluorescent label
Metaphase I
Anaphase I
Figure What prevents the separation of sister chromatids at anaphase I of meiosis?
Metaphase II OR
Anaphase II ? ? ? ?
Mature
spores ? ? ? ?
Spore
Two of three possible arrange-
ments of labeled chromosomes

29. RESULTS 100 80 60 Spore cases (%) 40 20 Shugoshin+ Shugoshin–
Fig b
RESULTS
100 80
Figure What prevents the separation of sister chromatids at anaphase I of meiosis? 60
Spore cases (%) 40 20
Shugoshin+
Shugoshin–

30. Possibility 2 Possibility 1 Two equally probable arrangements of
Fig
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
Figure The independent assortment of homologous chromosomes in meiosis

31. Possibility 2 Possibility 1 Two equally probable arrangements of
Fig
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
Figure The independent assortment of homologous chromosomes in meiosis
Metaphase II

32. Possibility 1 Possibility 2 Two equally probable arrangements of
Fig
Possibility 1
Possibility 2
Two equally probable
arrangements of
chromosomes at
metaphase I
Figure The independent assortment of homologous chromosomes in meiosis
Metaphase II
Daughter
cells
Combination 1
Combination 2
Combination 3
Combination 4

33. Prophase I Nonsister of meiosis chromatids held together
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Figure The results of crossing over during meiosis

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
Figure The results of crossing over during meiosis

35. 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
Figure The results of crossing over during meiosis
Anaphase I

36. 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
Figure The results of crossing over during meiosis
Anaphase I
Anaphase II

37. Recombinant chromosomes
Fig
Prophase I
of meiosis
Nonsister
chromatids
held together
during synapsis
Pair of
homologs
Chiasma
Centromere
TEM
Figure The results of crossing over during meiosis
Anaphase I
Anaphase II
Daughter
cells
Recombinant chromosomes

38. Prophase I: Each homologous pair undergoes
Fig. 13-UN1
Prophase I: Each homologous pair undergoes
synapsis and crossing over between nonsister
chromatids.
Metaphase I: Chromosomes line up as homolo-
gous pairs on the metaphase plate.
Anaphase I: Homologs separate from each other;
sister chromatids remain joined at the centromere.

39. Fig. 13-UN2 F H

40. Fig. 13-UN3

41. Fig. 13-UN4

42. You should now be able to:
Distinguish between the following terms: somatic cell and gamete; autosome and sex chromosomes; haploid and diploid
Describe the events that characterize each phase of meiosis
Describe three events that occur during meiosis I but not mitosis
Name and explain the three events that contribute to genetic variation in sexually reproducing organisms
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