1. Chapter 36:
Reproduction and Development

2. Concept 36.1: Both asexual and sexual reproduction occur in the animal kingdom
Asexual Reproduction 2

3. Sexual Reproduction: An Evolutionary Enigma
Figure
Asexual reproduction
Sexual reproduction
Female
Generation 1
Female
Generation 2
Male
Generation 3
Figure The “reproductive handicap” of sex (step 3)
Generation 4 3

4. (a) A. uniparens females (b) The sexual behavior of A. uniparens is
Figure 36.5
Ovary
size
Ovulation
Ovulation
Progesterone
Estradiol
Hormone
level
Time
Behavior
Female
Male-
like
Female
Male-
like
Figure 36.5 Sexual behavior in parthenogenetic lizards
(a) A. uniparens females
(b) The sexual behavior of A. uniparens is
correlated with the cycle of ovulation. 4

5. Variation in Patterns of Sexual Reproduction
Finding a partner to mate with can be challenging.
One solution is:
Others can undergo: 5

6. External and Internal Fertilization
External Fertilization
Internal Fertilization 6

7. Concept 36.2: Reproductive organs produce and transport gametes
Sexual reproduction in animals relies on sets of cells that are precursors for eggs and sperm 7

8. Variation in Reproductive Systems
Many animals have gonads
Some simple systems do not have gonads, but gametes form from undifferentiated tissue 8

9. Human Male Reproductive Anatomy
(Urinary bladder)
Seminal
vesicle
(Urinary duct)
(Rectum)
(Pubic bone)
Vas deferens
Erectile
tissue
Ejaculatory
duct
Figure 36.8 Reproductive anatomy of the human male
Urethra
Prostate gland
Penis
Vas deferens
Glans
Bulbourethral
gland
Epididymis
Testis
Prepuce
Scrotum
Figure 36.8 9

10. Human Female Reproductive Anatomy
Oviduct
Ovary
Uterus
(Urinary
bladder)
(Pubic bone)
(Rectum)
(Urethra)
Cervix
Body
Figure 36.9 Reproductive anatomy of the human female
Glans
Clitoris
Vagina
Prepuce
Major vestibular
gland
Labia minora
Labia majora
Vaginal opening
Figure 36.9 10

11. A Review of Meiosis:
Comparision of Meiosis and Mitosis:

12. Gametogenesis in Males
Figure 36.10a
Gametogenesis in Males
Epididymis
Seminiferous tubule
Testis
Primordial germ cell in embryo
Cross section of
seminiferous tubule
Mitotic divisions
Spermatogonial
stem cell 2n
Sertoli cell
nucleus
Mitotic divisions
Spermatogonium 2n
Mitotic divisions
Primary spermatocyte 2n
Meiosis I
Figure 36.10a Exploring human gametogenesis (part 1: spermatogenesis)
Secondary spermatocyte
n n
Lumen of
seminiferous
tubule
Meiosis II
Spermatids
(two stages)
Early
spermatid
n n n n
Tail
Neck
Differentiation
(Sertoli cells
provide nutrients)
Plasma
membrane
Midpiece
Head
Sperm cell n
n n n
Acrosome
Nucleus
Mitochondria 12

13. Gametogenesis in Females
Ovary
Primary oocyte
within follicle
Growing
follicle
In embryo
Primordial germ cell
Mitotic divisions
Mature follicle 2n
Oogonium
Mitotic divisions
Primary oocyte
(present at birth), arrested
in prophase of meiosis I 2n
Ruptured
follicle
Completion of meiosis I
and onset of meiosis II
First
polar
body n n
Secondary oocyte,
arrested at metaphase of
meiosis II
Figure 36.10b Exploring human gametogenesis (part 2: oogenesis)
Ovulated
secondary oocyte
Ovulation, sperm entry
Completion of meiosis II
Corpus luteum
Second
polar
body n
Fertilized egg n
Degenerating
corpus luteum 13

14. Concept 36.3: The interplay of tropic and sex hormones regulates reproduction in mammals
Human reproduction is coordinated by hormones from the hypothalamus, anterior pituitary, and gonads
Hypothalamus secretes:
Which, in turn, causes the anterior pituitary to secrete: 14

15. Hormonal Control of the Male System
Hypothalamus
GnRH
Anterior pituitary
FSH LH
Negative feedback
Negative feedback
Sertoli cells
Leydig cells
Figure Hormonal control of the testes
Inhibin
Spermatogenesis
Testosterone
Testis
Figure 36.12 15

16. Hormonal Control of the Female System
Control by hypothalamus
Inhibited by combination of
estradiol and progesterone
Hypothalamus
Stimulated by high levels
of estradiol 1
GnRH
Anterior pituitary
Inhibited by low levels of
estradiol 2
FSH LH
(b)
Pituitary gonadotropins
in blood 6 LH
FSH 3
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation
(c)
Ovarian cycle 7 8
(3D animation)
Growing follicle
Corpus
luteum
Maturing
follicle
Degenerating
corpus luteum
Follicular phase
Ovulation
Luteal phase
Estradiol secreted
by growing follicle in
increasing amounts
Progesterone and
estradiol secreted
by corpus luteum 4
(d)
Ovarian hormones
in blood
Peak causes
LH surge
(see ) 5 6
Figure The reproductive cycles of the human female 10
Estradiol 9
Progesterone
Estradiol level
very low
Progesterone and estra-
diol promote thickening
of endometrium
(e)
Uterine (menstrual) cycle
Endometrium
Figure 36.13
Menstrual flow phase
Proliferative phase
Secretory phase
Days 5 10 14 15 20 25 28 16

17. Control by hypothalamus Inhibited by combination of
Figure 36.13a
(a)
Control by hypothalamus
Inhibited by combination of
estradiol and progesterone
Hypothalamus
Stimulated by high levels
of estradiol 1
GnRH
Anterior pituitary
Inhibited by low levels of
estradiol 2
FSH LH
(b)
Pituitary gonadotropins
in blood 6
Figure 36.13a The reproductive cycles of the human female (part 1: FSH and LH levels) LH
FSH
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation 3
Days 5 10 14 15 20 25 28 17

18. Corpus luteum Degenerating corpus luteum Maturing follicle
Figure 36.13b
(b)
Pituitary gonadotropins
in blood 6 LH
FSH 3
FSH and LH stimulate
follicle to grow
LH surge triggers
ovulation
(c)
Ovarian cycle 7 8
Figure 36.13b The reproductive cycles of the human female (part 2: ovarian cycle)
Corpus
luteum
Degenerating
corpus luteum
Growing follicle
Maturing
follicle
Follicular phase
Ovulation
Luteal phase
Estradiol secreted
by growing follicle in
increasing amounts
Progesterone and
estradiol secreted
by corpus luteum 4
Days 5 10 14 15 20 25 28 18

19. Corpus luteum Degenerating corpus luteum Maturing follicle
Figure 36.13c
(c)
Ovarian cycle 7 8
Corpus
luteum
Degenerating
corpus luteum
Growing follicle
Maturing
follicle
Follicular phase
Ovulation
Luteal phase
Estradiol secreted
by growing follicle in
increasing amounts
Progesterone and
estradiol secreted
by corpus luteum 4
(d)
Ovarian hormones
in blood
Peak causes
LH surge
(see ) 6 5
Figure 36.13c The reproductive cycles of the human female (part 3: ovarian hormone levels) 10 9
Estradiol
Progesterone
Estradiol level
very low
Progesterone and estra-
diol promote thickening
of endometrium
Days 5 10 14 15 20 25 28 19

20. Progesterone and estra- diol promote thickening of endometrium
Figure 36.13d
(d)
Ovarian hormones
in blood
Peak causes
LH surge
(see ) 6 5 10 9
Estradiol
Progesterone
Estradiol level
very low
Progesterone and estra-
diol promote thickening
of endometrium
(e)
Uterine (menstrual) cycle
Endometrium
Figure 36.13d The reproductive cycles of the human female (part 4: menstrual cycle)
Menstrual flow phase
Proliferative phase
Secretory phase
Days 5 10 14 15 20 25 28 20

21. Uterine/Menstrual Cycle
Ovarian Cycle
Uterine/Menstrual Cycle

22. Menopause- What Is It?
After about ______cycles, human females undergo menopause, which is defined as
Menopause is very unusual among animals 22

23. Menstrual Versus Estrous Cycles23

24. Concept 36.4: Fertilization, cleavage, and gastrulation initiate embryonic development
Across animal species, embryonic development involves common stages occurring in a set order
Fertilzation Animation: 24

25. EMBRYONIC DEVELOPMENT Sperm Zygote
Figure 36.14
EMBRYONIC DEVELOPMENT
Sperm
Zygote
Adult
frog
Egg
FERTILIZATION
CLEAVAGE
Metamorphosis
Blastula
GASTRULATION
Figure Developmental events in the life cycle of a frog
ORGANO- GENESIS
Larval
stages
Gastrula
Tail-bud
embryo 25

26. Sperm plasma membrane Sperm nucleus Acrosomal process Basal body
Figure
Sperm plasma
membrane
Sperm
nucleus
Acrosomal
process
Basal body
(centriole)
Actin
filament
Sperm
head
Cortical
granule
Fused
plasma
membranes
Figure The acrosomal and cortical reactions during sea urchin fertilization (step 5)
Acrosome
Perivitelline
space
Hydrolytic enzymes
Jelly coat
Fertilization
envelope
Vitelline layer
Sperm-
binding
receptors
Egg plasma membrane 26

27. Acrosomal reaction: plasma membrane
Figure 36.16 1 2 3 4 6 8 10 20 30 40 50 5 60 90
Binding of sperm to egg
Acrosomal reaction: plasma membrane
depolarization (fast block to polyspermy)
Seconds
Increased intracellular calcium level
Cortical reaction (slow block to polyspermy)
Formation of fertilization envelope complete
Figure Timeline for the fertilization of sea urchin eggs
Increased protein synthesis
Minutes
Fusion of egg and sperm nuclei complete
Onset of DNA synthesis
First cell division 27

28. Cleavage and Gastrulation
50 m
(a) Fertilized egg
(b) Four-cell stage
(c) Early blastula
(d) Later blastula
Figure Cleavage in an echinoderm embryo
Figure 36.17 28

29. Digestive tube (endoderm) Anus (from blastopore)
Figure 36.18
Animal
pole
Blastocoel
Mesenchyme cells
Vegetal plate
Vegetal
pole
Blastocoel
Filopodia
Archenteron
Mesenchyme cells
Blastopore
Figure Gastrulation in a sea urchin embryo
50 m
Key
Blastocoel
Future ectoderm
Ectoderm
Future mesoderm
Archenteron
Future endoderm
Mouth
Blastopore
Mesenchyme
(mesoderm forms
future skeleton)
Digestive tube (endoderm)
Anus (from blastopore) 29

30. ECTODERM (outer layer of embryo)
Figure 36.19
ECTODERM (outer layer of embryo)
Epidermis of skin and its derivatives (including sweat glands,
hair follicles)
Nervous and sensory systems
Pituitary gland, adrenal medulla
Jaws and teeth
Germ cells
MESODERM (middle layer of embryo)
Skeletal and muscular systems
Circulatory and lymphatic systems
Excretory and reproductive systems (except germ cells)
Dermis of skin
Adrenal cortex
Figure Major derivatives of the three embryonic germ layers in vertebrates
ENDODERM (inner layer of embryo)
Epithelial lining of digestive tract and associated organs
(liver, pancreas)
Epithelial lining of respiratory, excretory, and reproductive tracts
and ducts
Thymus, thyroid, and parathyroid glands 30

31. Human Conception, Embryonic Development, and Birth
Conception occurs in:
The resulting zygote begins cleavage about ____ hours after fertilization and produces a blastocyst after ____ more days
A few days later, the embryo implants into the endometrium of the uterus
Gestation is: 31

32. (a) From ovulation to implantation
Figure 36.20 3
Cleavage 4
Cleavage
continues.
Ovary 2
Fertilization
Uterus 5
Implantation 1
Ovulation
Endometrium
(a) From ovulation to implantation
Figure Formation of a human zygote and early postfertilization events
Endometrium
Inner
cell
mass
Cavity
Trophoblast
Blastocyst
(b) Implantation of blastocyst 32